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  • Chemistry  (38,463)
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  • Numerical Methods and Modeling  (1,287)
  • Fisheries
  • 2020-2023  (33)
  • 1995-1999  (39,745)
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  • 1
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    The International Collective in Support of Fishworkers (ICSF) | India
    Publication Date: 2022-02-21
    Description: Yemaya No. 63, dated May 2021, features articles from US, The Netherlands, Myanmar, Senegal, and an article on women in fisheries and human rights. The article from the US by Linda Behnken argues that a growing coalition of small-scale, community-based fishers is calling for the recognition and protection of Alaska’s invaluable coastal fisheries during COVID-19. The article from the Netherlands by Cornelie Quist looks at the challenges facing women engaged in small-scale fishing and supplying fish through retailers and how they found new ways to directly reach consumers. The conversation between Miranda Bout and Cornelie Quist focuses on how they combined new product development with the use of social media to contact their customer base during the pandemic-induced disruption of traditional marketing chains. The article by Elena Finkbeiner, Juno Fitzpatrick and Whitney Yadao-Evans looks at recent media revelations and scientific research that have brought increased attention to human-rights violations and the myriad social issues facing fisheries, but with a disproportionate focus on labour-rights violations at sea and in industrial fishing operations. The systemic inequalities combined with the effects of COVID-19 exacerbated vulnerabilities of women to health risks, food and livelihood security. The article from Senegal by Aby Dia from Lumière Synergie pour le Développement (LSD), in collaboration with WoMin African Alliance, South Africa, narrates the story of traditional women fish processors from the Bargny who have been, for more than a decade, struggling against development projects that jeopardise their environment, health and livelihoods. In order to preserve their livelihoods, women processors in Senegal have come together to oppose the Tosyali steel project. The European Network of Women in Fisheries and Aquaculture in Europe (AKTEA) urges the Office of the Commissioner for the Environment, Oceans and Fisheries to integrate gender into all aspects of European fishing policy. The Profile column looks at how Linda Behnken became a fisher in Alaska and how fishing has shaped her individuality and work. Natalie Sattler says that fishing for halibut, sablefish and salmon from the sparkling waters of the Pacific along with her children and at the same time passion for working with the Alaska Longline Fishermen’s Association and the Alaska Sustainable Fisheries Trust is an immense challenge.
    Description: Published
    Description: Refereed
    Keywords: Fishing Communities ; Women in fisheries ; Gender ; Small-scale fisheries ; Aquaculture ; Fisheries
    Repository Name: AquaDocs
    Type: Book/Monograph/Conference Proceedings
    Format: 12p.
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  • 2
    Publication Date: 2022-06-28
    Description: Las pesquerías basadas en las agregaciones reproductivas pueden amenazar a especies como los pargos que tienen conductas gregarias durante el período reproductivo. Esta nota ofrece elementos que sugieren la existencia de sitios de agregación no registrados previamente y no protegidos en el Parque Nacional Cayos de San Felipe (PNCSF), región suroccidental de Cuba. La información tradicional obtenida de pescadores locales y trabajadores del parque se corroboró con muestreos cualitativos y cuantitativos de peces de arrecifes y datos de pesquerías locales del 2014. En la época de reproducción de pargos (mayo a julio) se observaron grupos de entre 40-100 ejemplares de Lutjanus cyanopterus, Lutjanus synagris y Lutjanus jocu en los arrecifes de la zona occidental del PNCSF (camellones entre 15-30 m de profundidad cerca del borde de la plataforma). Dentro de esa área, se señalan dos sitios que parecen ser utilizados para agregaciones de predesove, por lo que requieren protección y ser estudiados. Los censos cuantitativos confirmaron que en mayo y junio la zona occidental tiene densidad alta de pargos adultos. También, el pico de captura de estas especies ocurrió en la época reproductiva. Se comprobó que las pesquerías se realizaron durante las migraciones de peces hacia el borde de la plataforma en áreas de la zona occidental del PNCSF, y que más del 60% de los individuos tuvieron gónadas maduras (antes de desovar). Esta información debe incentivar el estudio de las agregaciones de desove en esta región de Cuba, la protección de especies amenazadas y áreas de alta significación ecológica y la implementación de pesquerías sostenibles.
    Description: Fisheries based on reproductive aggregations can threaten species such as snappers that have gregarious behavior during the reproductive period. This note provides evidence to support the existence of aggregation sites, not previously registered and unprotected, in the National Park San Felipe Keys (NPSFK), southwestern region of Cuba. Traditionalinformation obtained from local fishermen and from the park staff was complemented with qualitative and quantitative fish reef censuses and local fisheries data in 2014. In the reproductive season of snappers (May to July) groups of between 40-100 specimens of Lutjanus cyanopterus, Lutja- nus synagris and Lutjanus jocu were observed in the western area of the NPSFK on the reefs (spoor and grove between 20-30 m deep close to the platform edge). Within that area two sites are indicated that can be used for prespawning aggregation, so they require protection and study. Quanti- tative censuses confirmed that in May and June the western zone has high density of adult snappers. Also, the peak of capture of these snapper species occurred in the reproduc- tive season. It was found that fisheries carried out during fish migrations to the edge of the shelf in areas of the western area of the NPSFK and more than 60% of the individuals had mature gonads (before spawning). This information should promote the study of spawning aggregations in this region of Cuba, the protection of threatened species and areas of high ecological significance and the implementation of sustainable fisheries.
    Description: Published
    Description: Refereed
    Keywords: Región suroccidental de Cuba ; Desove ; Pesquerías ; Migration routes ; Spawning ; Fisheries ; Rutas migraciones
    Repository Name: AquaDocs
    Type: Journal Contribution
    Format: pp.54-65
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  • 3
    Publication Date: 2022-09-14
    Description: The ICES Workshop on ICES reference points (WKREF2) was tasked review the WKREF1 report and based on the outcome develop updated guidelines for the ICES reference points system and recommendations for ACOM consideration. The WKREF1 report has suggested 5 key recom- mendations to simplify and harmonise the ICES reference points framework representing a ma- jor change to the current guidelines. At WKREF2, we detailed discussions and four key concerns were raised about the proposed approach. The first related to the simplification of rules to define Blim. Around two thirds of category 1 stocks would end up as WKREF1 “Blim Type 2” where Blim would be set as a fraction of B0. The Allee effect or “depensation” maybe more important than previously thought and should be furthered explored for ICES stocks since it has important consequences for Blim. A number of challenges and issues around defining Blim using the current guidelines were documented. Some suggestions on improvement criteria were discussed including using classifiers to define spas- modic stocks and using change point algorithms to address non-stationary productivity regimes. However, further work is need to make these approaches operational and there was no consen- sus that the WKREF1 Blim types should replace the current guidelines. WKREF1 recommended that the FMSY proxy should be based on a biological proxies and should be less than the deterministic FMSY. It was pointed out that the stochastic FMSY estimated in EqSim for example, is lower than the deterministic FMSY and that the current guidelines ensure that the FMSY should not pose a more than 5% risk to Blim. A large amount of work described in WD 1 was carried out to develop an MSE framework to consistency and robustness test a candidate refer- ence point system for North East Atlantic stocks. However, WKREF2 recommended that further work needs to be carried out to condition and test the simulation framework before the conclu- sions could be adopted by ICES and incorporated into the guidelines. A number of considerations for defining MSY related reference points were discussed including using model validation and prediction skill to ensure that ICES provide robust and credible ad- vice. There is evidence that density dependence (DD) is important in the majority of ICES stocks (68% in recruitment and 54% in growth). The correct prediction of the shape and strength of density-dependence in productivity is key to predicting future stock development and providing the best possible long-term fisheries management advice. A suggested approach to use surplus production models (SPMs) to account for DD in FMSY was suggested and discussed but there was no consensus on whether that approach was appropriate. There was consensus that the FECO approach as a means of adapting target fishing mortality to medium-term changes in productiv- ity should be included in the guidelines subject to a benchmark and ACOM approval. While WKREF1 and 2 focused mainly on Category 1 stocks ToR c) called for a “simplified and harmonised set of guidelines for estimating MSY and precautionary reference points applicable in the advice framework across various ICES stock categories.” Ideally the ICES assessment cat- egories should provide equivalent risk across all stocks. This issue was discussed but no recom- mendations emerged. There was no consensus a revised reference point framework was proposed at WKREF2. How- ever, it was agreed that it should be presented here for further discussion at ACOM and other fora. The key feature of the suggested approach is that the stock status evaluation is treated in- dependent of the Advice Rule (AR). The main feature of the system is that the biomass trigger is not linked to a stock status evaluation, it is linked to the expected biomass when fishing at the target fishing mortality, in contrast to the current ICES approach. It also entailed that FMSY would also become an upper limit of fishing mortality and that the advised fishing mortality would be set at or lower than that level. WKREF2 did not discuss what to do in situations where SSB〈 Blim or alternative forms of HCR for the advice rule. Building community understanding and con- sensus around simplified and harmonised guidelines has yet to be achieved. A further workshop WKREF3 will be required to achieve that aim. The report includes 6 recommendations for ACOM consideration.
    Description: ICES
    Description: The main objective of the workshop was to review the recommendations of WKREF1 and con- sider how these might feed into a new reference points framework and guidelines for ICES. There were a number of presentations on the wider issues of best practice for reference points, the Allee effect, density dependence and the WKIRISH approach. The starting point was to try and develop a set of simplified and harmonised guidelines based on the WKREF1 report rather than evolving the current guidelines to include the WKREF1 conclusions. A key aspect of the meeting was to allow for discussions in order to build a shared understanding of the strengths and weakness of the current framework and of the new framework emerging from WKREF1.
    Description: Published
    Description: Non Refereed
    Keywords: ICES ; Reference points ; Management advice ; Fisheries ; Fishery management reference points
    Repository Name: AquaDocs
    Type: Report
    Format: 103pp
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  • 4
    Publication Date: 2022-10-26
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Dowd, S., Chapman, M., Koehn, L., & Hoagland, P. The economic tradeoffs and ecological impacts associated with a potential mesopelagic fishery in the California Current. Ecological Applications, 32(4), (2022): e2578, https://doi.org/10.1002/eap.2578.
    Description: The ocean's mesopelagic zone (200–1000 m) remains one of the most understudied parts of the ocean despite knowledge that mesopelagic fishes are highly abundant. Apex predators from the surface waters are known to consume these fishes, constituting an important ecological interaction. Some countries have begun exploring the potential harvest of mesopelagic fishes to supply fishmeal and fish oil markets due to the high fish abundance in the mesopelagic zone compared with overfished surface waters. This study explored the economic and ecological implications of a moratorium on the harvest of mesopelagic fishes such as lanternfish off the US West Coast, one of the few areas where such resources are managed. We adapted a bioeconomic decision model to examine the tradeoffs between the values gained from a hypothetical mesopelagic fishery with the potential values lost from declines in predators of mesopelagic fishes facing a reduced prey resource. The economic rationale for a moratorium on harvesting mesopelagics was sensitive both to ecological relationships and the scale of the nonmarket values attributed to noncommercial predators. Using a California Current-based ecological simulation model, we found that most modeled predators of mesopelagic fishes increased in biomass even under high mesopelagic harvest rates, but the changes (either increases or decreases) were small, with relatively few predators responding with more than a 10% change in their biomass. While the ecological simulations implied that a commercial mesopelagic fishery might not have large biomass impacts for many species in the California Current system, there is still a need to further explore the various roles of the mesopelagic zone in the ocean.
    Description: Sally Dowd acknowledges sponsorship from the WHOI Summer Student Fellowship and the Rausser College of Natural Resources Honors Program at UC Berkeley. This project would not have been possible without the guidance provided by Kama Thieler and Carl Boettiger. Porter Hoagland acknowledges funding from the Audacious Project, a collaborative endeavor, housed at TED and the J. Seward Johnson Fund in support of the Marine Policy Center at WHOI.
    Keywords: Bioeconomic model ; Fisheries ; Mesopelagic fishes ; Moratorium ; Nonmarket value ; Predators ; Rpath ; Willingness-to-pay values
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 5
    Publication Date: 2022-10-26
    Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Kourantidou, M., Hoagland, P., Dale, A., & Bailey, M. Equitable allocations in northern fisheries: bridging the divide for Labrador Inuit. Frontiers in Marine Science, 8, (2021): 590213, https://doi.org/10.3389/fmars.2021.590213.
    Description: Canada has undertaken commitments to recognize the rights of Indigenous Peoples in fisheries through policies and agreements, including Integrated Fishery Management Plans, the Reconciliation Strategy, and Land Claim Agreements (LCAs). In addition to recognizing rights, these commitments were intended to respect geographic adjacency principles, to enhance the economic viability of Indigenous communities, and to be reflective of community dependence on marine resources. We examined the determinants of quota allocations in commercial fisheries involving Nunatsiavut, Northern Labrador, the first self-governing region for the Inuit peoples in Canada. It has been argued that current fishery allocations for Nunatsiavut Inuit have not satisfied federal commitments to recognize Indigenous rights. Indicators that measure equity in commercial allocations for the turbot or Greenland halibut (Reinhardtius hippoglossoides) and northern shrimp (Pandalus borealis) fisheries were identified and assessed. In these two cases, historical allocations continue to predominate for allocations based upon equity or other social or economic considerations. We illustrate equity-enhancing changes in the quota distribution under scenarios of different levels of inequality aversion, and we make qualitative assessments of the effects of these allocations to Nunatsiavut for socioeconomic welfare. This approach could benefit fisheries governance in Northern Labrador, where federal commitments to equity objectives continue to be endorsed but have not yet been integrated fully into quota allocations.
    Description: This research was undertaken with funding from the Canada First Research Excellence Fund through the Ocean Frontier Institute (MK and MB) and the Johnson Endowment of the Woods Hole Oceanographic Institution’s (WHOI) Marine Policy Center (PH).
    Keywords: Fisheries ; Allocations ; Equity ; Indigenous rights ; Access
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 6
    Publication Date: 2022-05-27
    Description: Buesseler, K., Jin, D., Kourantidou, M., Levin, D., Ramakrishna, K., Renaud, P., Ausubel, J., Baltes, K., Gjerde, K., Holland, M., Kostel, K., LaCapra, V., Martin, A., Sosik, H., Thorrold, S., Tierney, T., Joyce, K., Renier, N., Taylor, E. (2022). The Ocean Twilight Zone’s Role in Climate Change. Woods Hole Oceanographic Institution, 32 pp.
    Description: The ocean twilight zone (more formally known as the mesopelagic zone) plays a fundamental role in global climate. It is the mid-ocean region roughly 100 to 1000 meters below the surface, encompassing a half-mile deep belt of water that spans more than two-thirds of our planet. The top of the ocean twilight zone only receives 1% of incident sunlight and the bottom level is void of sunlight. Life in the ocean twilight zone helps to transport billions of metric tons (gigatonnes) of carbon annually from the upper ocean into the deep sea, due in part to processes known as the biological carbon pump. Once carbon moves below roughly 1000 meters depth in the ocean, it can remain out of the atmosphere for centuries to millennia. Without the benefits of the biological carbon pump, the atmospheric CO 2 concentration would increase by approximately 200 ppm 1 which would significantly amplify the negative effects of climate change that the world is currently trying to curtail and reverse. Unfortunately, existing scientific knowledge about this vast zone of the ocean, such as how chemical elements flow through its living systems and the physical environment, is extremely limited, jeopardizing the efforts to improve climate predictions and to inform fisheries management and ocean policy development.
    Description: Funding is: The Audacious Project housed at TED
    Keywords: Climate ; Mesopelagic ; Twilight Zone ; Fisheries ; Carbon Dioxide Removal ; Ocean ; Biological Carbon Pump ; Solubility Pump ; Carbon ; Marine Snow
    Repository Name: Woods Hole Open Access Server
    Type: Other
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  • 7
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    In:  aqdchief@seafdec.org.ph | http://aquaticcommons.org/id/eprint/18569 | 2002 | 2015-11-15 16:06:30 | 18569 | Southeast Asian Fisheries Development Center, Aquaculture Department
    Publication Date: 2022-08-02
    Description: This paper summarizes the results of the experiments on the induced breeding and larval rearing of milkfish (Chanos chanos) during the 1979 season. Milkfish larvae could be reared successfully without the use of trochophore larvae of oysters as feed during the first few days. In order to induce the ovulation of wild adult milkfish a higher dose of human chorionic gonadotropin hormone is required.
    Keywords: Fisheries ; Chanos chanos ; ISEW ; Philippines ; marine environment ; Brood stocks ; Fish culture ; Fish larvae ; Food organisms ; Induced breeding ; Larval development ; Sex hormones
    Repository Name: AquaDocs
    Type: article
    Format: application/pdf
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    Format: 1-3
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  • 8
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    In:  library@seafdec.org.ph | http://aquaticcommons.org/id/eprint/20100 | 17342 | 2016-02-24 22:18:26 | 20100 | Southeast Asian Fisheries Development Center, Aquaculture Department
    Publication Date: 2022-08-02
    Description: An outline is given of aquaculture and fisheries in Asia, providing information of use to students whose work can influence laws, rules, policy and regulations on aquaculture and fisheries, with the view in mind to sustainable aquaculture. In this issue, the following countries are examined: China, Indonesia, and Bangladesh.
    Keywords: Aquaculture ; Fisheries ; Fishery management ; Aquaculture development ; Aquaculture regulations ; Marine aquaculture ; Freshwater aquaculture ; Fishery industry ; Asia ; Bangladesh ; China
    Repository Name: AquaDocs
    Type: article
    Format: application/pdf
    Format: application/pdf
    Format: 7-8
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  • 9
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    In:  library@seafdec.org.ph | http://aquaticcommons.org/id/eprint/20067 | 2002 | 2016-03-04 15:16:24 | 20067 | Southeast Asian Fisheries Development Center, Aquaculture Department
    Publication Date: 2022-08-02
    Keywords: Fisheries ; Aquaculture ; Vietnam ; Sri Lanka ; Sri Lanka ; Vietnam ; brackishwater environment ; freshwater environment ; marine environment ; Aquaculture ; Aquaculture techniques ; Brackishwater aquaculture ; Feed ; Fish culture ; Fish diseases ; Fisheries ; Fishery data ; Food organisms ; Freshwater aquaculture ; Marine aquaculture ; Marine fisheries ; Mollusc culture ; Pond culture ; Seaweed culture ; Shrimp culture
    Repository Name: AquaDocs
    Type: article
    Format: application/pdf
    Format: application/pdf
    Format: pp.9-10, 27
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  • 10
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    In:  library@seafdec.org.ph | http://aquaticcommons.org/id/eprint/20055 | 2002 | 2016-03-03 11:33:32 | 20055 | Southeast Asian Fisheries Development Center, Aquaculture Department
    Publication Date: 2022-08-02
    Keywords: Fisheries ; Aquaculture ; Asia ; Cambodia ; India ; Asia ; Cambodia ; India ; Myanmar ; Myanmar ; brackishwater environment ; freshwater environment ; marine environment ; Aquaculture ; Aquaculture development ; Aquaculture economics ; Aquaculture techniques ; Brackishwater aquaculture ; Catching methods ; Culture effects ; Environmental impact ; Fish culture ; Fisheries ; Fishery development ; Fishery resources ; Fishery statistics ; Freshwater aquaculture ; Marine aquaculture ; Shrimp culture ; Sustainability ; Trade
    Repository Name: AquaDocs
    Type: article
    Format: application/pdf
    Format: application/pdf
    Format: pp.9-10, 29
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  • 11
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26291 | 23782 | 2019-04-08 09:42:05 | 26291 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Keywords: Fisheries ; Pollution ; Indonesia ; Heavy metals ; Chemical pollution ; Pollution monitoring
    Repository Name: AquaDocs
    Type: book_section
    Format: application/pdf
    Format: application/pdf
    Format: 10-19
    Format: 10
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  • 12
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26293 | 23782 | 2019-03-22 03:49:21 | 26293 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Keywords: Fisheries ; Myanmar ; Heavy metals ; Cadmium ; Lead ; Mercury ; Biological sampling ; Fish ; Fishery products ; Seafood
    Repository Name: AquaDocs
    Type: book_section
    Format: application/pdf
    Format: application/pdf
    Format: 38-46
    Format: 9
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  • 13
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    Secretariat, Southeast Asian Fisheries Development Center | Bangkok, Thailand
    In:  http://aquaticcommons.org/id/eprint/26259 | 2002 | 2019-03-01 05:56:06 | 26259 | Southeast Asian Fisheries Development Center, Secretariat
    Publication Date: 2022-08-02
    Description: Round scad exploration by purse seine in the waters of western Philippines was conducted from April 22 to May 7, 1998 for a period of five (5) fishing days with a total catch of 7.3 tons and an average of 1.5 tons per setting. Dominant species caught were Decapterus spp. having 70.09% of the total catch, followed by Selar spp. at 12.66% and Rastrelliger spp. 10.70%. Among the Decapterus spp. caught, D. macrosoma attained the highest total catch composition by species having 68.81% followed by D. kurroides and D.russelli with 0.31% and 1.14% respectively. The round scad fishery stock was composed mainly of juvenile fish (less than 13 cm) and Age group II (13 cm to 14 cm). Few large round scad at Age group IV and V (20 cm to 28 cm) stayed at the fishery. Other fishes caught were: Auxis rochei (0.85%), A. thazard (0.12%), Caranx spp. (0.45%), Emmilichthys nitidus (0.58%), Euthynnus affinis (0.42%), Leiognathus ruconius (0.58%), Loligo sp. (0.31%), Megalaspis cordyla (0.09%), Rastrelliger spp. (10.70%), Sardinella longiceps (0.03%), Scomberoides lysan (0.24%), Selar spp. (12.66%), Sphyraena spp. (0.90%), Thunnus albacares (0.96%) and others (1.02%). Tuna and tuna like fishes such as yellowfin tuna, eastern little tuna, bullet tuna, frigate tuna and oceanic squid are distributed in the upper latitudes of the survey area. On the other hand, round scads, big-eyed scads and Indian mackerels are dominantly present in the lower latitudes of the survey area.
    Keywords: Fisheries ; Exploratory fishing ; Purse seining ; Age composition ; Catch composition ; Fishery surveys ; Carangid fisheries ; South China Sea ; Philippines ; Rastrelliger ; Decapterus
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    Format: 49-64
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  • 14
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    Training Department, Southeast Asian Fisheries Development Center | Samut Prakarn, Thailand
    In:  http://aquaticcommons.org/id/eprint/26215 | 17342 | 2019-02-08 06:25:54 | 26215 | Southeast Asian Fisheries Development Center, Training Department
    Publication Date: 2022-08-02
    Description: Presented in this paper is the status of the fishery industry in Brunei Darussalam. Specifically, it discussed the following topics: fishery management strategies, zonation scheme, licencing, the use of poisons and explosives, the minimum cod-end mesh size for trawlers, closed areas, enhancement of fishing grounds, and the enforcement activities.
    Keywords: Fisheries ; Fishery resources ; Fishery management ; Fisheries ; Ecological zonation ; Licensing ; Fish poisoning ; Catching methods ; Illegal fishing ; Explosive fishing ; Fishing gear ; Season regulations ; Fishing grounds
    Repository Name: AquaDocs
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    Format: application/pdf
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    Format: 34-40
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  • 15
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26295 | 23782 | 2019-03-22 08:39:12 | 26295 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Keywords: Fisheries ; Thailand ; Cadmium ; Lead ; Mercury ; Biological sampling ; Fish ; Fishery products ; Seafood
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    Type: book_section
    Format: application/pdf
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    Format: 53-58
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  • 16
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26292 | 23782 | 2019-03-22 03:43:09 | 26292 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Keywords: Fisheries ; Malaysia ; Cadmium ; Lead ; Mercury ; Biological sampling ; Fish ; Fishery products ; Seafood
    Repository Name: AquaDocs
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    Format: application/pdf
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    Format: 20-37
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  • 17
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    Secretariat, Southeast Asian Fisheries Development Center | Bangkok, Thailand
    In:  http://aquaticcommons.org/id/eprint/26258 | 2002 | 2019-03-01 06:00:19 | 26258 | Southeast Asian Fisheries Development Center, Secretariat
    Publication Date: 2022-08-02
    Description: An exploratory tuna longline fishing survey was conducted using the research and training vessels of the Southeast Asian Fisheries Development Center, the 1,178 GT MV SEAFDEC and the Bureau of Fisheries and Aquatic Resources, the 165 GT MV MAYA-MAYA in the South China Sea Waters, West of the Philippines from April to May, 1998. A total of 3,796 hooks was set in sixteen (16) fishing stations. There were no tuna caught during the entire survey but only minor and irrelevant species like the Pacific lancetfish, sharks and an opah species, Lampris guttatus. The important fishing and oceanographic factors during the survey and other research results on longline are described and analyzed. Additional longline studies within and near the Philippines territorial waters are also presented to substantiate the research results of the joint SEAFDEC/BFAR resource exploratory.
    Keywords: Fisheries ; Exploratory fishing ; Catch composition ; Fishery surveys ; Longlining ; Tuna fisheries ; South China Sea ; Philippines
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  • 18
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26299 | 23782 | 2019-03-27 06:00:01 | 26299 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Keywords: Chemistry ; Fisheries ; Malaysia ; Pesticides ; Biological sampling ; Fish ; Fishery products ; Biochemical analysis ; Lethal limits
    Repository Name: AquaDocs
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  • 19
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26300 | 23782 | 2019-03-27 05:58:36 | 26300 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Keywords: Aquaculture ; Chemistry ; Fisheries ; Myanmar ; Pesticides ; Biological sampling ; Fish ; Fishery products ; Lethal limits
    Repository Name: AquaDocs
    Type: book_section
    Format: application/pdf
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26307 | 23782 | 2019-03-27 03:35:56 | 26307 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Keywords: Fisheries ; Indonesia ; Histamines ; Biological sampling ; Fish ; Fishery products ; Quality control
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    Format: application/pdf
    Format: 116-123
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  • 21
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26303 | 23782 | 2019-03-27 05:51:15 | 26303 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Keywords: Chemistry ; Fisheries ; Thailand ; Pesticides ; Biological sampling ; Fish ; Fishery products ; Dried products ; Lethal limits
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  • 22
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26309 | 23782 | 2019-03-27 03:49:31 | 26309 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Keywords: Fisheries ; Myanmar ; Histamines ; Biological sampling ; Biochemical analysis ; Fish ; Fishery products
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    Format: application/pdf
    Format: application/pdf
    Format: 129-133
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  • 23
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26826 | 23782 | 2019-11-21 00:56:12 | 26826 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Description: Presented in the paper is the standard procedure in the determination of K value which is an index to measure the enzymatic freshness of fish and squid. Specifically, reagents, apparatus and the analytical procedures needed and the calculations are presented.
    Keywords: Chemistry ; Fisheries ; Manuals ; Culture media ; Analysis ; Analytical techniques ; Methodology ; Chemical analysis ; Fishery products ; Fish inspection ; Fishery industry ; Food technology ; Standards ; Specifications
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  • 24
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26825 | 23782 | 2019-11-21 00:52:35 | 26825 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Description: Presented in the paper is the standard procedure in measuring K value in fish meat by means of the freshness testing paper technique.
    Keywords: Chemistry ; Fisheries ; Manuals ; Culture media ; Analysis ; Analytical techniques ; Methodology ; Chemical analysis ; Fishery products ; Fish inspection ; Fishery industry ; Food technology ; Standards ; Specifications
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  • 25
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26802 | 23782 | 2019-11-12 05:28:20 | 26802 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Description: Presented in the paper is the standard procedure in the measurement of pH in the fresh fish meat. Specifically, the procedures in sampling and sample preparation, apparatus and reagents required, and the analytical procedures are presented.
    Keywords: Chemistry ; Fisheries ; Manuals ; Culture media ; Analysis ; Analytical techniques ; Methodology ; Chemical analysis ; Microbiological analysis ; Fishery products ; Processed fishery products ; Fish inspection ; Fishery industry ; Food additives ; Food technology ; Standards ; Specifications ; pH
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  • 26
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26842 | 23782 | 2019-11-15 07:54:48 | 26842 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Description: Starch is commonly used in the production of fish jelly products as an extender and as binding agent. The paper provides the methodology in the determination of starch in fish jelly products. Instructions for sample preparation and the reagents needed are presented. Detailed procedures in the determination of the starch in a sample are provided.
    Keywords: Chemistry ; Fisheries ; Manuals ; Culture media ; Analysis ; Analytical techniques ; Methodology ; Chemical analysis ; Fishery products ; Fishery industry ; Food technology ; Standards ; Specifications ; Starch ; Additives ; Food additives
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  • 27
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26881 | 23782 | 2019-11-05 02:46:02 | 26881 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Description: Monitoring and investigative work undertaken in the Philippines regarding dinoflagellate blooms are described. Chronological observations of the occurrence of red tides, aerial surveys, spatial distribution of the dinoflagellate and the physical environment are discussed. Fishing and the examination of gut content of fish and mussels and bioassay tests are detailed. Incidents of paralytic shellfish poisoning in the Philippines are considered briefly.
    Keywords: Fisheries ; Health ; Environmental monitoring ; Red tides ; Public health ; Medicine ; Dangerous organisms ; Philippines
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    Format: application/pdf
    Format: 52-79
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  • 28
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26885 | 23782 | 2019-11-05 02:23:34 | 26885 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Description: A report is made of the first incidence occurring of paralytic shellfish poisoning in Thailand in May 1983, following an extensive bloom of Trichodesmium erythraeum. Investigations undertaken regarding the source of the toxicity are outlined.
    Keywords: Fisheries ; Health ; Biological poisons ; Public health ; Red tides ; Shellfish ; Dangerous organisms ; Thailand
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    Format: application/pdf
    Format: 90-91
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  • 29
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26879 | 23782 | 2019-11-05 02:54:38 | 26879 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Description: A brief account is given of recent cases of paralytic shellfish poisoning in Sabah, Malaysia, and toxicological studies undertaken. Hydrography surveys, underwater observations after the occurrence of the red tides and plankton studies and monitoring of red tides are discussed.
    Keywords: Fisheries ; Health ; Shellfish ; Toxicity tests ; Red tides ; Public health ; Dangerous organisms ; Malaysia
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  • 30
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26852 | 23782 | 2019-11-15 07:36:44 | 26852 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Description: Cholera is an acute specific infection caused by the organism, Vibrio cholera. Diagnosis may be confirmed by the presence of large numbers of the comma-shaped bacilli on direct microscopic examination of a fecal or vomitus smear, and by the isolation of the organism on culture. Fish and shellfish have been identified as vehicles of cholera. Large numbers of V. cholera must usually be ingested to cause cholera. Thus problems often occur when poor handling and inadequate refrigeration have allowed the organism to multiply. Presented in the paper is the methodology of determining the presence of Vibrio cholera in fish and fishery products.
    Keywords: Chemistry ; Fisheries ; Manuals ; Culture media ; Analysis ; Analytical techniques ; Methodology ; Fishery products ; Fishery industry ; Food technology ; Standards ; Specifications ; Aerobic bacteria ; Microbiological analysis ; Microorganisms ; Pathogenic bacteria ; Pathogens ; Health and safety ; Public health ; Microbial contamination ; Vibrio cholerae
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    Secretariat, Southeast Asian Fisheries Development Center | Bangkok, Thailand
    In:  http://aquaticcommons.org/id/eprint/26890 | 23782 | 2019-11-14 01:01:29 | 26890 | Southeast Asian Fisheries Development Center, Secretariat
    Publication Date: 2022-08-02
    Description: Fishery statistics in Brunei Darussalam have been collected by the Department of Fisheries since the 1940s. In the early 1980s, a number of statistics were collected, such as catch and effort data of artisanal fishermen, aquaculture statistics, processing statistics as well as data from major wet markets focusing on the amount, prices of marketed fish either from the local fishermen or imported. In 1984, the collection of statistics on commercial fishing was started. The statistics have been used in the formulation of fishery management and development policies as well as for sectoral development. Following a brief account of the responsibility and statistic collections of the Department of Fisheries, an examination is made of employment in the fishery sector, fisheries production, fish marketed and the GDP for the fishery industry. Fisheries in Brunei Darussalam is a very healthy industry, where production is well below the maximum allowable harvestable limit of 20,000 tons at 30%. The Department is embarking to increase production from the capture fishery to reduce the country's dependence on imported fish; the same applies for aquaculture, in order to complement production from the capture fisheries. The processing sector is also increasing in importance, especially with the increase in the number of capture fishery licenses, and the demand for quality and value-added products.
    Keywords: Fisheries ; Marine fisheries ; Fishery statistics ; Aquaculture development ; Aquaculture statistics ; Fish catch statistics ; Marine aquaculture ; Freshwater aquaculture ; Fishery development ; Marine ; Brackish ; Freshwater
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26843 | 23782 | 2019-11-15 07:52:55 | 26843 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Description: Sodium chloride is an important additive for the production of fish jelly products. It extracts the salt soluble protein to give the gel strength of the final product. The paper provides the methodology in the determination of the amount of sodium chloride in fish jelly products. Instructions for sample preparation and the reagents needed are presented. Detailed procedures in the determination of the salt in a sample are provided.
    Keywords: Chemistry ; Fisheries ; Manuals ; Culture media ; Analysis ; Analytical techniques ; Methodology ; Chemical analysis ; Fishery products ; Fishery industry ; Food technology ; Standards ; Specifications ; Additives ; Food additives ; Salts ; Sodium chloride
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  • 33
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26851 | 23782 | 2019-11-14 01:29:31 | 26851 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publication Date: 2022-08-02
    Description: Food poisoning due to Vibrio parahaemolyticus is a food-borne infection resulting from the ingestion of a large number of this organism (about 106-109 viable cells). The major symptoms are diarrhea and abdominal pain with headache, fever, and vomiting also occurring. The organisms are excreted during the acute stage of the illness after which they decrease rapidly. The differentiation of V. parahaemolyticus from other pathogenic species of Vibrio is based mainly on salt tolerance, Voges-Proskauer reaction, fermentation of sucrose, and growth at 43°C. Presented in the paper is the methodology of determining the presence of Vibrio cholera in fish and fishery products.
    Keywords: Chemistry ; Fisheries ; Manuals ; Culture media ; Analysis ; Analytical techniques ; Methodology ; Fishery products ; Fishery industry ; Food technology ; Standards ; Specifications ; Aerobic bacteria ; Microbiological analysis ; Microorganisms ; Pathogenic bacteria ; Pathogens ; Health and safety ; Public health ; Microbial contamination ; Vibrio parahaemolyticus ; Vibrio cholerae
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  • 34
    ISSN: 1432-0975
    Keywords: Key words Otolith ; Chemistry ; ICP-MS ; Stock discrimination ; Epinephelus striatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract  We examined the utility of otolith minor and trace element chemistry, assayed with inductively coupled plasma mass spectrometry (ICP-MS), as a means of delineating population structure in the Nassau grouper (Epinephelus striatus). We characterized the elemental composition of otoliths collected in 1993 from three locations in Exuma Sound, Bahamas and from Glover Reef, Belize in 1995. A single location in Exuma Sound was sampled in 1994 to test temporal variability in otolith composition. Five elements (Ca, Zn, Sr, Ba and Pb) were routinely detected, at levels significantly above background, by solution-based ICP-MS. Results from analysis of variance of elemental data, expressed as a ratio to Ca, indicated that there were no significant differences among the Exuma locations for any element, but significant variability was found between Glover Reef and the pooled Exuma localities for Zn/Ca, Sr/Ca and Ba/Ca ratios. Significant inter-annual differences at one Exuma Sound location was restricted to Ba/Ca ratios. Discriminant function analysis correctly classified 86% and 95% of the Belize and pooled Exuma sites, respectively. Otoliths from Belize were characterized by low Zn/Ca and high Ba/Ca and Pb/Ca ratios compared to otoliths from fish collected in Exuma Sound. Although differences in Ba levels may be related to upwelling at Glover Reef, more data are needed to definitely link otolith composition with regional differences in water chemistry.
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  • 35
    ISSN: 1432-1009
    Keywords: Reservoir ; Fisheries ; Breeding and wintering waterbirds ; Raising water levels ; Habitat change
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A new, higher dam was installed at Kerkini Reservoir in 1982, causing habitat and landscape disruption. A decrease in the area of grassland and shallow water areas, the rapid disappearance of reedbeds, the appearance of beds ofNymphaea, and the disappearance of half the forest area were all observed between 1982 and 1991. With the new hydrological regime, a lacustrine system was created, with an extensive, rather deep (4–8 m), pelagic zone favorable for the development of coarse fish species throughout the year. After 1982, an increase in fishing effort and a change in the relative abundance of fish species in the catch, including the disappearance of eels and wels, were observed. The impact of the rise in the water level of breeding aquatic birds led to a general decline in species typical of marshy habitats in favor of species preferring deeper open water habitats. A decrease was recorded in bird species that feed largely on invertebrates and to a lesser extent fish (e.g., glossy ibis) and that require extensive shallow feeding areas. There was a decline in geese, whose nests were regularly flooded, and a major increase in piscivorous birds, particularly diving birds (e.g., cormorants), which prefer deeper open water and benefitted directly from the large increase in coarse fish biomass. The disappearance of birds breeding in flooded meadows (e.g., black-winged stilts) and of those restricted to reedbeds (e.g., marsh harrier) occurred from 1983. Over the same period, the changes in populations of wintering birds at Kerkini were different from those occurring in other wetlands in northern Greece. The changes recorded in the populations of wintering birds at Kerkini did not therefore result from overall regional trends but from the major habitat modifications that occurred to this wetland. As for breeding birds, strictly piscivorous species increased greatly as a result of the increased availability of fish, but also due to the appearance of many suitable night roosting sites (flooded trees) and to the great increase in the area of open water greater than 2 m deep. Today, Kerkini has become the most important breeding site in Greece for a majority of colonial waterbirds. In contrast, wintering shorebirds practically disappeared. The many changes recorded in the status of breeding and wintering birds at Kerkini can mostly be explained by the changes that occurred in the functioning of the ecosystem and in the habitat structure following the inauguration of the new hydrological regime. These changes did not all occur at the same time: some were immediate and others required a delay before they could be detected.
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  • 36
    Electronic Resource
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    Environmental management 20 (1996), S. 523-539 
    ISSN: 1432-1009
    Keywords: Water control ; Floodplain ; Fisheries ; Bangladesh ; Chandpur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Bangladesh is a very flat delta built up by the Ganges—Brahmaputra—Meghna/Barak river systems. Because of its geographical location, floods cause huge destruction of lives and properties almost every year. Water control programs have been undertaken to enhance development through mitigating the threat of disasters. This structural approach to flood hazard has severely affected floodplain fisheries that supply the major share of protein to rural Bangladesh, as exemplified by the Chandpur Irrigation Project. Although the regulated environment of the Chandpur project has become favorable for closed-water cultured fish farming, the natural open-water fishery loss has been substantial. Results from research show that fish yields were better under preproject conditions. Under project conditions per capita fish consumption has dropped significantly, and the price of fish has risen beyond the means of the poor people, so that fish protein in the diet of poor people is gradually declining. Bangladesh is planning to expand water control facilities to the remaining flood-prone areas in the next 15–20 years. This will cause further loss of floodplain fisheries. If prices for closed-water fish remain beyond the buying power of the poor, alternative sources of cheap protein will be required.
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  • 37
    Electronic Resource
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    Astrophysics and space science 224 (1995), S. 81-84 
    ISSN: 1572-946X
    Keywords: Chemistry ; Depletions ; Shocks ; IRAS 05338-0624 ; NGC 1333 IRAS 4
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract High resolution interferometer and single-dish observations of young, deeply embedded stellar systems reveal a complex chemistry in the circumstellar environments of low to intermediate mass stars. Depletions of gas-phase molecules, grain mantle evaporation, and shock interactions actively drive chemical processes in different regions around young stars. We present results for two systems, IRAS 05338-0624 and NGC 1333 IRAS 4, to illustrate the behavior found and to examine the physical processes at work.
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  • 38
    Electronic Resource
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    Boundary layer meteorology 85 (1997), S. 197-222 
    ISSN: 1573-1472
    Keywords: Turbulence ; Chemistry ; Closure ; Convective boundary layer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract We study the interactions of chemistry and turbulent mixing of tracersin the convective boundary layer with a second-order closure model,including higher order chemistry terms. In order to limit the number of predictive equations we prescribe the profiles for ¯w¯Θ, ¯w¯θ ¯θ and the lengthscale l. However, for model validation we treat temperature and humidity asinert tracers, and compare the results with profiles observed during theAir Mass Transformation Experiment, and with similarity expressions for thesurface layer. We find good agreement of the mean profiles, but the (co-)variances are slightly underpredicted. Furthermore, the model usesdiagnostic equations expressing third moments of concentration in terms ofsecond moments and their vertical derivatives. They are compared withlarge-eddy model results, showing good agreement and, therefore, thesimplifications are justified. The model is applied to the transport of two gases subject to one bimolecular reaction. The importance of concentration correlations on themean transformation rate is studied. For two gases diffusing in oppositedirections we find for moderate and fast chemistry a 50% and90% decreased transformation rate due to the negatively correlatedconcentrations. These values are similar to large-eddy results of Schumannand Sykes et al. For two bottom-up tracers we find that the covariance ofboth reactive species is either positive or negative, increasing or reducingthe effective transformation rate depending on the Damköhler number (the ratio of the turbulent and the chemistry timescale). A significantdirect influence of chemistry on the flux divergence is found in bothcases. According to the model the effective transport to mid-levels of theboundary layer is increased when two reactive tracers diffuse in oppositedirections, and decreased in the case of two bottom-up tracers.
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  • 39
    Electronic Resource
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    Journal of science education and technology 5 (1996), S. 193-201 
    ISSN: 1573-1839
    Keywords: Chemistry ; chemistry education ; multiple intelligences ; imagery ; visual-spatial thinking
    Source: Springer Online Journal Archives 1860-2000
    Topics: Natural Sciences in General , Technology
    Notes: Abstract Chemistry has evolved from a science dominated by mathematics into a science highly dependent on spatial-visual intelligence. Yet the chemical content of introductory courses remains taught essentially the same as 40–50 years ago. Chemistry, today, is recognized by chemists as the molecular science. Yet, school chemistry is alienated from that perception. Thanks to the computer, young people are more comfortable with visual imaging than their instructors were at the same age. Thus the time is rife to reinvigorate chemistry education by means of the visual-spatial approach, an approach wholly in conformance with the way modern chemistry is thought about and practiced.
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  • 40
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    Environmental biology of fishes 45 (1996), S. 219-235 
    ISSN: 1573-5133
    Keywords: Ecology ; Behaviour ; Evolution ; Cichlids ; Fisheries ; Conservation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Ecological conditions in tropical lacustrine systems are considered by focusing on the evolution, maintenance, exploitation and vulnerability of fish communities in the African Great Lakes. The exceptionally high biodiversities in the littoral/sublittoral zones of the very ancient, deep, clear, permanently stratified rift lakes Tanganyika and Malawi, are contrasted with the simpler systems in their pelagic zones, also with biodiversity in the much younger, shallower Victoria, the world's largest tropical lake.
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  • 41
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    Astrophysics and space science 233 (1995), S. 125-137 
    ISSN: 1572-946X
    Keywords: Interstellar Medium ; Dark Clouds ; Chemistry ; Bistability ; C-shock Waves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Shock waves perturb the chemical state of the interstellar gas. We consider the effects of C-shocks on the composition of molecular clouds, for a range of values of the pre-shock gas density and magnetic induction. The time required to re-establish equilibrium in the post-shock gas depends on the initial conditions and can become very large. The significance of the two known chemical phases of dark clouds and of bistability is considered in this context.
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  • 42
    Electronic Resource
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    Astrophysics and space science 233 (1995), S. 161-164 
    ISSN: 1572-946X
    Keywords: Stars ; Chemistry ; Diffusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We have assessed the role of diffusion in determining chemical abundances in molecular interface regions. Chemical models have been developed which include the appropriate diffusion terms and that are appropriate to a narrow diffusion region (∼0.01pc) that may exist at the interface between a dark core and a hot, shocked T-Tauri wind. We have assumed pressure balance throughout and have calculated the chemical abundances as functions of time and position through the interface. The results show that significant enhancements of detectable molecules/transitions are expected (e.g. CO J=6→5, OH and CH). Using a realistic value of the diffusion coefficient a diffusive region of dimension 0.01pc may be established within about 104 years. In general it seems likely that diffusion processes are highly significant on these and smaller lengthscales.
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  • 43
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    Environmental biology of fishes 43 (1995), S. 381-391 
    ISSN: 1573-5133
    Keywords: Fisheries ; Irrigation ; Reproductive seasonality ; Sarotherodon galilaeus ; Species richness ; Water quality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis A preliminary study of the ecology and commercial fish catches was carried out in the Toho-Todougba, Ahouangan and Dati lakes (1500 ha) in southern Benin (West Africa) over a period of 18 consecutive months. Water quality, species richness, and the reproductive biology of the dominant species, Sarotherodon galilaeus, were examined. Unlike Lagoon Toho-Todougba, lakes Ahouangan and Dati are less favourable for fish production because of their high total iron content and their relative low pH. The study revealed the existence of 19 species belonging to eleven (11) families: 16 species in Lagoon Toho-Todougba,12 in Lake Ahouangan, and 7 in Lake Dati. Lakes Ahouangan and Dati had a relatively high faunal similarity whereas Lagoon Toho-Todougba exhibited a relatively low faunal similarity with the former systems. In Lagoon Toho-Todougba, six cichlid species were the most important component of the fishery: Sarotherodon galilaeus, Tilapia guineensis, T. zillii, T. mariae, Chromidotilapia guntheri, Hemichromis fasciatus. Three catfish species Chrysichthys auratus, Clarias agboyiensis, and Clarias lazera were harvested in low abundances. Some other fish, such as Polypterus senegalus senegalus, Protopterus annectens and Heterotis niloticus were captured sporadically, with H. niloticus appearing more consistently in catches than the others. Although not abundant, Gymnarchus niloticus and the African pike, Hepsetus odoe, were almost always present in the catches. Ctenopoma kingsleyae appeared only in Ahouangan. Some predatory species, such as Notopterus afer and Xenomystus nigri, are encountered only in lakes Ahouangan and Dati. In Lagoon Toho-Todougba, Sarotherodon galilaeus had a sex ratio (♂: ♀) of 0.49:1, and size at maturation was estimated as 12.3 cm TL. The spawning period extended from May to September with the peak occurring in July. Fecundity was correlated to log-body length (r = 0.74) and log-body weight (r = 0.76). Fish catches were estimated at 389 kg ha−1 year−1; about 73% of which was Sarotherodon galilaeus. The overexploitation of juvenile fish and the use of this lagoon for the irrigation of palm tree plantations have reduced fish recruitment and mean size.
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  • 44
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Der Einfluß von 3-Phenylenbismaleimid auf die Werkstoffeigenschaften von CaCO3 gefüllten Polypropylen-Verbundstoffen wurde untersucht. Die Verarbeitungstemperatur spielte eine entscheidende Rolle bei der Herstellung der Verbundwerkstoffe. Bei Verarbeitungstemperaturen oberhalb der Bismaleimid-Zersetzungstemperatur zeigte die Bismaleimid-Verbindung einen positiven Effekt. Die chemische Zusammensetzung der modifizierten Verbunde wurde mit den mechanischen Eigenschaften korreliert. Basierend auf ESCA-Analysen werden Wechselwirkungen zwischen dem Polymeren und CaCO, diskutiert.
    Notes: The effect of 3-phenylene bismaleimide on the mechanical performance of an inorganic filler-based polypropylene composite was studied. The selection of processing temperature played a significant role in the preparation of such composites. A positive effect of the bismaleimide compound was obtained for a processing temperature above the decomposition temperature of bismaleimide. The chemical composition of the modified composite was correlated to its mechanical strength by experimentation involving a rotatable design. An interaction between polymer and CaCO3 has been proposed based on ESCA analysis.
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  • 45
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    Angewandte Makromolekulare Chemie 224 (1995), S. 33-48 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Chemische und mechanische Eigenschaften von Zwischenprodukten der PE-Schrumpfschlauch-Produktion wurden bei unterschiedlichen Compound-Zusammensetzungen (PE, ein aromatisches Amin oder Phenolderivat als Antioxidans und in einigen Fällen ein Flammschutzmittel und/oder eine Elastomerkomponente) untersucht.Während der Herstellung, besonders während der durch Elektronenstrahlung initiierten Vernetzung, nimmt die thermooxidative Stabilität des Materials gegenüber der des compoundierten Granulats ab. Das aromatische Amin scheint bei gleicher Zusammensetzung das wirksamere und strahlungsbeständigere Antioxidans im Vergleich zum Phenolderivat zu sein. Die Oxidationsstabilität der hergestellten Schrumpfschläuche wird nicht von der Qualität des eingesetzten PE-Ausgangsgranulats beeinflußt.Durch die Alterung des Materials ändern sich die mechanischen Eigenschaften geringfügig. Die Elastomerzugabe bewirkt keine Änderung von Zugfestigkeit und Reißdehnung. Die Stabilität des Endprodukts ist bei weitem ausreichend, um den Spannungen, die beim Schrumpfen während des Gebrauchs auftreten, standzuhalten. Die gute Zugfestigkeit des Materials wird durch die Alterung ebenfalls nicht beeinträchtigt.Bei der Extrusion des Granulats tritt keine nennenswerte Änderung des Molekulargewichts bzw. der Molekulargewichtsverteilung auf. Durch die Bestrahlung wird das Material vernetzt und zu mehr als 50% unlöslich, und seine thermooxidativen Eigenschaften ändern sich deutlich gegenüber dem ursprünglichen PE und dem daraus compoundierten Material.
    Notes: Some chemical and mechanical properties of intermediate products obtained in the production of PE heat-shrinkable tubes were studied at different compositions of the material containing PE, antioxidant (aromatic amime or phenol) and, in some cases, flame retardant and/or an elastomer.In the course of the production phase, the thermooxidative stability decreases compared to that of compounded granulate. The greatest decrease is caused by irradiation. The aromatic amine seems to be a more effective antioxidant at similar compositions than the phenol derivative, and it shows a better resistance against irradiation. The oxidative stability of the finished shrinkable tubes is not affected by the quality of commercial granulate (initial polyethylene).Mechanical properties change slightly upon ageing, and the introduction of the elastomer did not alter the tensile strength and elongation at break. The remaining stability of the end product was still high enough to bear the stress of shrinking in use, and the good tensile strength of the material did not decrease upon thermal ageing either.In the extrusion of the granulated compound no significant change in the distribution and average molecular weight took place. Irradiation produced more than 50% insoluble fraction and the thermooxidative properties of the crosslinked sample changed significantly compared to the original PE and to the compound prepared from it.
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  • 46
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    Angewandte Makromolekulare Chemie 224 (1995), S. 89-96 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: In the present work oxygen index (OI) measurements and thermogravimetric analysis (TG) for a series of polyurethanes based on diols and isocyanate were conducted. It was found that a correlation exists between some of the thermal degradation parameters obtained from TG and OI-values. Analysis of experimental results confirms that the amount of mass loss at 250°C is directly proportional to the OI-value. It was also found that the logarithmic temperatures of maximal decomposition rates are directly proportional to the OI-values.
    Notes: In der vorliegenden Arbeit wurden für eine Serie von Polyurethanen auf der Basis von Diol und Isocyanat der Sauerstoffindex (SI) gemessen und die thermische Zersetzung mittels thermogravimetrischer Analyse (TG) untersucht. Dabei wurde ein Zusammenhang zwischen einigen Parametern der thermischen Zersetzung und den SI-Werten gefunden. Die Auswertung der experimentellen Ergebnisse zeigte, daß die Höhe des Massenverlustes bei 250°C und die SI-Werte direkt proportional zueinander sind. Derselbe Zusammenhang besteht auch zwischen dem Logarithmus der Temperatur bei der maximalen Zersetzungsgeschwindigkeit und den SI-Werten.
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  • 47
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    Angewandte Makromolekulare Chemie 224 (1995), S. 109-114 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Poly(acrylsäre-co-acrylamid) wurde mit Zinkoxid und Kryolith (Na3AlF6) in unterschiedlichen Verhältnissen gemischt und bei Raumtemperatur zu Zahnzementen ausgehärtet. IPDT, Temperaturen bei maximaler Abbaugeschwindigkeit, Aktivierungsenergien und Frequenzfaktoren des thermischen Abbaus der Proben wurden aus thermogravimetrischen Messungen ermittelt. Die Probe mit 20 Gew.-% Kryolith in der Füllstoffmischung ist thermisch sehr stabil.
    Notes: Dental cement compositions made by mixing poly(acrylic acid-co-acrylamide) and mixtures of zinc oxide and cryolite (Na3AIF6) in various proportions of 10-50 wt.-% (w/w) were cured at room temperature. From thermogravimetric analyses of the samples, the integral procedural decomposition temperatures (IPDT), maximum decomposition temperatures, activation energies and frequency factors were evaluated. The cured cement sample containing 20 wt.-% cryolite in the filler mixture is thermally very stable.
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  • 48
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    Angewandte Makromolekulare Chemie 224 (1995), S. 133-144 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die wasserlöslichen aromatischen Diazonium-Doppelsalze p-Diazodiphenylaminchlorid/Zinkchlorid (DZS-1) und p-Diazoanisolchlorid/Zinkchlorid (DZS-2) wurden auf ihre Verwendbarkeit als photobleichbare Farbstoffe in der Kontrastverstärkungslithographie untersucht. Nach Untersuchung der Bleicheigenschaften der hergestellten Salze wurde DZS-1 in wäßrigen Lösungen mit Poly(vinylalkohol) als Kontrastverstärkungssystem eingesetzt. Die thermische Stabilität, der Resistkontrast, die Bestrahlungsparameter und andere Bleicheigenschaften wurden untersucht. Im Vergleich zu einem handelsüblichen i-Linien-Photoresist beträgt das Kontrastverhältnis der DZS-1/PVA CEL-Schicht 1,67.
    Notes: Water soluble aromatic diazonium double salts, p-diazodiphenylamine chloride zinc chloride (DZS-1) and p-diazoanisol chloride zinc chloride (DZS-2), have been evaluated as photobleachable dyes for contrast enhancement lithography. After testing the bleaching characteristics, aqueous solutions of DZS-1 and poly(vinyl alcohol) were used as a contrast enhancement material. Thermal stability, resist contrast, exposure parameters and other bleaching characteristics of the photobleachable membranes were investigated. A. commercial i-line photoresist was used to evaluate the contrast ratio of the DZS-1/PVA CEL layer. The contrast ratio obtained in this investigation is 1.67.
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  • 49
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    Angewandte Makromolekulare Chemie 224 (1995), S. 167-178 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Methylen-4,4′-diphenyldiisocyanat und zwei unterschiedliche Bisoxazoline wurden für Kopplungsreaktionen in mit Carboxygruppen terminierten flüssigkristallinen Poly(ethylenterephthalat-co-oxybenzoat)en eingesetzt. Um definierte Bedingungen zu gewährleisten, erfolgte die Synthese von Copolyestern mit unterschiedlichen Carboxygruppenkonzentrationen. Die Bestimmung des Carboxygruppengehalts wird beschrieben.Es erfolgt ein Vergleich des Kopplungsverhaltens beider Arten von Kettenverlängerern. Es konnte nachgewiesen werde, daß die Bisoxazoline bedeutend schneller reagieren als das Diisocyanat. Durch einen geringen Überschuß and Bisoxazolin in der Reaktionsmischung konnte einer thermischen Schädigung vorgebeugt werden. Abhängig von der Menge an zugegebenem Koppler wurden bei den modifizierten Copolyestern Oxazolinendgruppen beobachtet. Außerdem werden mögliche Vernetzungsreaktionen und die thermische Stabilität diskutiert.
    Notes: Methylene-4,4′-diphenyldiisocyanate and two different bisoxazolines were used for coupling reactions in carboxy-terminated liquid crystalline poly(ethylene terephthalate-co-oxybenzoate). In order to guarantee defined conditions, copolyesters with different carboxylic group concentrations were synthesized. The determination of the carboxylic group content is described.The coupling behaviour of both types of chain extenders has been compared. It was evidenced that the bisoxazolines reacted significantly faster than the diisocyanate. A slight excess of bisoxazoline in the reaction mixture prevented thermomechanical degradation. Depending on the amount of coupling agent added, an oxazoline termination of the copolyester was observed. Additionally, probable crosslinking reactions and the thermal stability have been discussed.
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    Angewandte Makromolekulare Chemie 224 (1995), S. 201-201 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 51
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    Angewandte Makromolekulare Chemie 225 (1995), S. 11-20 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Der Einfluß von 3-Phenylenbismaleimid auf die Werkstoffeigenschaften von mit Talkum und Zeolith gefüllten Polypropylen-Verbundstoffen wurde untersucht. Durch geeignete Planung des Aufbaus kann die Produkteigenschaft optimiert werden. Die Kapazität zur Füllstoffaufnahme schwankt bei Polypropylen je nach Art des Füllstoffs. Ein hochbelastbarer Verbundstoff kann aus einem geeignet modifizierten, mit Zeolith gefüllten Polypropylen hergestellt werden, auch wenn der Füllstoff in der Verbundmatrix dominiert. Als Ursache dieser Verstärkung wird eine verbesserte Wechselwirkung zwischen dem Polymeren und dem Füllstoff angenommen.
    Notes: The effect of 3-phenylene bismaleimide as a modifier for talc and zeolite-filled polypropylene composites has been studied. The usefulness of the experimental design to assure best product properties has also been illustrated. Polypropylene shows a variable degree of filling capacity depending on the type of filler. A high-strength composite can be prepared with suitably modified zeolite-filled polypropylene even if filler is the dominant phase in the composite matrix. An improved interfacial interaction between polypropylene and filler is proposed to be the reason for this improvement of strength.
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    Angewandte Makromolekulare Chemie 225 (1995), S. 51-61 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die katalytische Oligomerisation von 1-Decen wurde mit Komplexverbindungen mehrerer Übergangsmetalle (Co(II), Co(III), Zr(IV), Ti(IV), Cr(III), V(V)) und Alkyl-aluminiumhalogeniden als Cokatalysatoren durchgeführt. Mit einem Chrom(III)-Et3Al2Cl3-Katalysatorsystem konnten Dimere (C20), Trimere (C30) und Tetramere (C40) von 1-Decen erhalten werden. Die kinematischen Viskositäten und Fließpunkte der hydrierten Oligomere wurden bestimmt und mit den Werten handelsüblicher Proben verglichen. Ein Mechanismus für die Oligomerisation von 1-Decen mit diesem Katalysatorsystem wird vorgeschlagen.
    Notes: The catalytic oligomerization of 1-decene has been carried out employing several transition metal complexes of Co(II), Co(III), Zr(IV), Ti(IV), Cr(III), V(V) in combination with alkyl aluminum halides as cocatalysts. The chromium(III)-Et3Al2Cl3 system exhibits good oligomerizing activity yielding dimers (C20), trimers (C30) and tetramers (C40) of 1-decene. The kinematic viscosities and pour points of hydrogenated oligomers have been determined and compared with those of commercial samples. The probable mechanism of oligomerization of 1-decene on this catalyst is described.
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  • 53
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    Angewandte Makromolekulare Chemie 225 (1995), S. 99-107 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Single-component formulations of epoxy resins with reactive accelerators must be storable. The preparation of several blocked accelerators is described. The basicity of tertiary amines, which correlates with accelerating effects, as well as acidity and structure of polyphenols and modified novolacs influences the extend of blocking. The curing process was investigated by measurements of gel time and viscosity.
    Notes: Einkomponentige Epoxidharzsysteme mit effizienten Reaktionsbeschleunigern müssen lagerstabil sein. Daher wurden Versuche unternommen, Beschleuniger auf Basis von tertiären Aminen mit modifizierten Phenolnovolaken zu blockieren. Das Ausmaß der Blockierung ist sowohl von der Basizität der Amine, die mit der beschleunigenden Wirkung korreliert, als auch von der Acidität und dem strukturellen Aufbau der modifizierten Phenole abhängig. Die Bewertung der Härtungseigenschaften erfolgte über Gelzeitbestimmungen und Viskositätsmessungen.
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  • 54
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Bruchzähigkeit von Phenolphthalein-Poly(etherketon) bei 190°C wurde mit zwei verschiedenen Methoden bestimmt, der konventionellen Rißwachstumsmethode und der „stress whitening zone“-Methode. Die gute Übereinstimmung der Ergebnisse zeigt, daß letztere Methode zur Bestimmung der Rißinitiierung einiger Polymerer herangezogen werden kann, für die das „blunting line concept“ nicht geeeignet ist.
    Notes: Fracture toughness values of phenolphthalein poly(ether ketone) (PEK-C) at 190°C were determined by two different methods, i.e. the conventional crack growth method and the crack stress whitening zone method, which show consistent results. This indicates that the crack stress whitening zone method can be used to determine the crack initiation of some polymers for which the blunting line concept is unsuitable.
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  • 55
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    Angewandte Makromolekulare Chemie 226 (1995), S. 13-22 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Stabilitätskonstanten und zugehörige thermodynamische Parameter (ΔH°, ΔS°) eines intermakromolekularen Komplexes aus Poly(acrylsäure-co-acrylamid), Poly(methacrylsäure-co-acrylamide) und Poly(N-vinylpyrrolidon) wurden mit bekannten Methoden bei verschiedenen Temperaturen bestimmt. Dabei wurde eine stufenweise Auflösung des Komplexes in Abhängigkeit von der Temperatur beobachtet, die mit den Stabilitätskonstanten und den thermodynamischen Parametern korreliert wurde.
    Notes: Stability constant and related thermodynamic parameters (ΔH° and ΔS°) of a multicomponent intermacromolecular complex consisting of poly(acrylic acid-coacrylamide), poly(methacrylic acid-co-acrylamide) and poly(N-vinylpyrrolidone) have been determined using known methods. A distinct stepwise disintegration of the complex at different temperatures has been observed, and this could be correlated with the stability constant and thermodynamic parameters calculated at various temperatures.
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  • 56
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    Angewandte Makromolekulare Chemie 226 (1995), S. 53-57 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Der Einfluß von Ultraschall auf die Polymerisation und Depolymerisation von Ethylmethacrylat und der Mechanismus des Kettenabbruchs wurden untersucht. Der Polymerisationsumsatz war unabhängig von den verwendeten Ultraschallbedingungen (800 W, 35 kHz). Depolymerisationsversuche mit Ultraschall bei 20°C zeigten, daß Kettenabbruch im wesentlichen durch Disproportionierung stattfindet; dabei werden Molekulargewichte nicht unter ca. 500000 erreicht.
    Notes: The effect of ultrasound in ethyl methacrylate polymerization and depolymerization and the chain termination mechanism for ethyl methacrylate have been studied. Polymerization conversion at 60°C did not depend on energy (80 W) and frequency (35 kHz) of ultrasound applied. In ultrasound depolymerization studies at 20°C the governing termination mechanism was found to be disproportionation and the lower limiting molecular weight was Mn = 500 000.
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  • 57
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    Angewandte Makromolekulare Chemie 226 (1995), S. 71-87 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The copolymerization of acrylonitrile with maleic anhydride was investigated to synthesize acylic reactive polymers for manufacture of membranes that serve as support for covalent enzyme immobilization. The free-radical copolymer synthesis was carried out in solution (N,N-dimethylformamide (DMF), dimethylacetamide (DMAC), γ-butyrolactone, ethylene carbonate), by precipitation polymerization (dioxane) as well as bulk polymerization. The polymers were characterized using IR spectroscopy, elementary analysis, NMR spectroscopy, gel permeation chromatography, viscosity measurements, osmometry and potentiometry.The kinetic parameters were followed by dilatometric measurements up to high conversions. The anhydride content in the monomer mixtures showed a significant influence on the rate of polymerization and the molecular weight. With raised concentration of anhydride the polymerization rate and molecular weights decreased. Film forming polymers (M̄η 〉 30 000 g/mol) can be obtained by all copolymerization procedures with exception of solution polymerization in DMF and DMAC, respectively. The content of maleic anhydride in the membrane polymers did not exceed 5 mol-%, even though the maleic anhydride content in the monomer mixtures was raised up to the equimolar mixture. Nevertheless, such low maleic anhydride content of prepared membranes is enough for successful enzyme immobilization with amyloglucosidase (copolymer was prepared in γ-butyrolactone, M̄η = 49 000 g/mol, cPMSA = 0,3 mol-%).
    Notes: Die Copolymerisation des Acrylnitrils mit Maleinsäureanhydrid (MSA) wurde mit dem Ziel untersucht, acylfunktionalisierte Reaktivpolymere mit Filmbildungseigenschaften herzustellen, um diese in der Anwendung als Membran für kovalente Enzymfixierungen zu nutzen. Die radikalinitiierte Synthese der Copolymeren wurde in Lösung (Dimethylformamid (DMF), Dimethylacetamid (DMAC), γ-Butyrolacton, Ethylencarbonat), durch Fällungscopolymerisation (Dioxan) sowie in Substanz durchgeführt.Die Polymercharakterisierung erfolgte durch IR-Spektroskopie, Elementaranalyse, Kernresonanzspektroskopie, Gelpermeationschromatographie, Viskosimetrie, Osmometrie und Potentiometrie.Die Kinetik wurde durch dilatometrische Untersuchungen bis zu hohen Umsätzen verfolgt. Danach weist der Anhydridgehalt im Monomergemisch einen signifikanten Einfluß auf die Bruttopolymerisationsgeschwindigkeit und die Molmasse der Polymeren auf. Mit steigendem Anhydridanteil wird die Bruttopolymerisationsgeschwindigkeit herabgesetzt und eine Verringerung der Molmasse herbeigeführt. Die Copolymerisation von Acrylnitril und Maleinsäureanhydrid führt mit Ausnahme der Lösungspolymerisation in DMF bzw. DMAC zu Polymeren mit Molmassen oberhalb 30 000 g/mol, was ihre Anwendung als Membran ermöglicht. Die Einbaurate an Maleinsäureanhydrid in den Membranpolymeren ist bis einschließlich einer äquimolaren Zusammensetzung des Monomergemischs nicht größer als 5 mol-%. Derartig niedrige MSA-Reaktivgruppenanteile erweisen sich jedoch als ausreichend, um an einer aus einem Lösungspolymerisat (γ-Butyrolacton, M̄η = 49 000 g/mol, cPMSA = 0,3 mol-%) formierten Membran eine Enzymimmobilisierung mit Amyloglucosidase nachzuweisen.
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    Angewandte Makromolekulare Chemie 226 (1995), S. 143-160 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Synthesen einer Aryl-alkyl-azodiisocyanat-Verbindung und einer Azoharnstoff-Modellsubstanz werden beschrieben. Aus dem Azodiisocyanat wurden durch Grenzflächen-Polyaddition neuartige Azoharnstoff-Polymer hergestellt. Die zahlenmittleren Molekulargewichte, bestimmt mit der Gelpermeationschromatographie (GPC), lagen zwischen 6000 und 9000. Die Photolyse- und Thermolysereaktionen der Modellsubstanzen und der Polymeren wurden mittels UV-Spektroskopie und Differentialkalorimetrie (DSC) verfolgt und mit den Ergebnissen von ähnlichen Azoamiden verglichen. Der photochemische Polymerabbau wurde mittels GPC untersucht.
    Notes: The synthesis of an aryl alkyl azo diisocyanate and a model azo urea is described. From the azo diisocyanate new azo polyureas were created by interfacial polyaddition. Molecular weights Mn in the range of 6000 to 9000 were determined by gel permeation chromatography (GPC). Photolysis and thermolysis of both, model compounds and polymers, were studied by UV-spectroscopy and differential scanning calorimetry (DSC), respectively, and the results were compared with those of similar azo amides. Photochemical polymer degradation was followed by GPC.
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    Angewandte Makromolekulare Chemie 226 (1995), S. 219-219 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Angewandte Makromolekulare Chemie 227 (1995), S. 69-85 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Thermotrop flüssigkristalline Copolyester aus Vanillinsäure (V), 4-Hydroxybenzoesäure (B) und Polyethylenterephthalat (E) wurden mittels 1H-NMR-Spektroskopie und Gelpermeationschromatographie (GPC) untersucht. Die neun möglichen Diaden konnten detektiert und zugeordnet werden. Die Abfolge der Grundeinheiten der V/B/E-Copolyester ändert sich mit zunehmendem B-Anteil von statistischer Verteilung zur Blockbildung und ist außerdem geringfügig von der Katalysatorkonzentration und der Polykondensationsdauer abhängig. Die GPC-Ergebnisse deuten darauf hin, daß die V/B/E-Copolyester engere Molekulargewichtsverteilungen aufweisen als die B/E-Copolyester. Mit von 0 bis 5 mol-% steigendem V-Anteil verengt sich die Molekulargewichtsverteilung. Die Gelpermeationschromatogramme der meisten V/B/E-Copolyester weisen im Unterschied zu den Einzelsignalen der B/E-Copolyester Dublett-Peaks auf.
    Notes: Thermotropic liquid-crystalline copolyesters made from vanillic acid (V), 4-hydroxybenzoic acid (B) and poly(ethylene terephthalate) (E) were examined by 1H-NMR and GPC investigations. Nine possible diads could be identified and assigned. The sequence distribution of V/B/E copolyesters tends to change from random to block with an increase of B content in the copolyesters. The sequence distribution also varies slightly with catalyst concentration and polycondensation time. GPC results suggest that the V/B/E copolyesters have narrower molecular weight distribution (MWD) than B/E copolyesters. The MWD of the copolyesters narrows gradually with increasing V content from zero to 5 mol-%. The GPC chromatograms of the most V/B/E copolyesters show double peaks, which is different from the single peak of the GPC chromatograms of the B/E copolyesters.
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  • 61
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    Angewandte Makromolekulare Chemie 227 (1995), S. 111-120 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Strahlungsbeständigkeit von vorbestrahltem Polypropylen mit 2,5 Gew.-% Ethylenanteil wurde mitr einem Copolymeren aus Polypropylen und einem nukleierenden Agens im Hinblick auf die Strahlungssterilisation von medizinischen Geräten verglichen. Die Transparenz des Propylen-Ethylen-Copolymeren wurde durch die Vorbehandlung verbessert. Im Vergleich mit der ebenfalls verbesserten Transparenz des Copolymeren aus Polypropylen und dem nukleierenden Agens wurde durch die Vorbestrahlung die Strahlungsbeständigkeit während der Bestrahlung und bei der Lagerung des bestrahlten Materials verbessert. Dies wird auf die geringere Kristallinität des vorbestrahlten Polypropylens aufgrund von bei der Bestrahlung gebildeten Verzweigungen zurückgeführt.
    Notes: The radiation stability of the pre-irradiated copolymer of polypropylene containing 2.5 wt.-% ethylene units is compared with a copolymer of polypropylene with a nucleating agent with regard to radiation sterilization of medical devices. It is found that transparency property of the propylene-ethylene copolymer is improved through pre-irradiation processes. This finding was compared with the co-polypropylene with nucleating agent which also gives a better transparency property. In comparison, it is found that pre-irradiated copolymer exhibits better radiation stability during irradiation and during storage after irradiation. The radiation stability of the pre-irradiated copolymer is due to its lower crystallinity caused by the formation of branches during the pre-irradiation process.
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  • 62
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    Angewandte Makromolekulare Chemie 227 (1995), S. 193-193 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 63
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Polydiaryldiazosulfide wurden durch Grenzflächenpolykondensation aus aromatischen Bisdiazoniumionen und Benzol-1,3-dithiol erhalten. Auf diese Weise wurden Molekulargewichte Mn von 3400 bis 11700 erreicht (GPC).Die neue Polymerklasse zeichnet sich durch hohe Photolabilität und relativ geringe Thermostabilität aus. Mittels UV-Spektroskopie wurde die Photolyse von Modellver-bindungen und Polymeren verfolgt, wobei in nahezu allen Fällen ein Zerfall 1. Ordnung beobachtet wurde. Der photochemische Kettenabbau konnte durch GPC-Untersuchungen verfolgt werden. Die thermische Stabilität der polymeren Diazosulfide wurde durch DSC-Messungen untersucht.
    Notes: Poly(diaryl diazosulfide)s were synthesized from aromatic bisdiazonium ions and benzene-1,3-dithiol via interfacial polycondensation. Number-average molecular weights Mn in the range of 3400 to 11700 were determined by gel permeation chromatography (GPC).The new polymer class is distinguished by high photosensitivity and low thermostability. First order kinetics during photolysis of nearly all polymers and model compounds under investigation was observed by means of UV spectroscopy. Polymer degradation upon irradiation was verified by GPC measurements. Thermal decay was followed by differential scanning calorimetry (DSC).
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  • 64
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Three different titration methods were proved with respect to accuracy, reproducibility and handling for the determination of maleic anhydride (MSA) content in acrylonitrile (AN) copolymers in form of poly(AN-co-MSA) and poly(AN-co-styrene-co-MSA). The comparison comprises (i) the combined method A/H characterized by the reaction of anhydride groups (AG) with aniline and titration of the formed monoacid with methanolic KOH (A) and the complete hydrolysis of AG and titration of acid groups (SG) with aqueous NaOH (H), (ii) method B based on the conversion of AG with n-butylamine (BA) and back-titration of unreacted amine with HClO4 in glacial acetic acid and (iii) method C consisting of the reaction of AG with p-chloroaniline (pCA) followed by Cl-determination after the Schöniger-decomposition. Whereas all mentioned methods are suitable for the determination of AG in the presence of initial SG, the combination of A/H additionally allows the simultaneous determination of AG and SG. In comparison with the other methods the combination of A/H is to be favoured due to the possibility to obtain additional information about SG and because of the better results in accuracy, reproducibility and handling. By means of FTIR spectroscopy the content of AG and SG was estimated qualitatively and a correlation between the spectroscopic and potentiometric data of AG was discovered.
    Notes: Zur Bestimmung des Maleinsäreanhydrid(MSA)-Gehaltes in Acrylnitril(AN)-Copolymeren des Typs Poly(AN-co-MSA) bzw. Poly(AN-co-Styrol-co-MSA) wurden drei verschiedene Titrationsmethoden hinsichtlich ihrer Richtigkeit, Reproduzierbarkeit sowie ihres Zeitaufwandes geprüft. Miteinander verglichen wurden (i) eine Methodenkombination A/H bestehend aus dem Teilschritt A, einer Umsetzung der Anhydridgruppen (AG) mit Anilin einschließlich der Titration der Monosäuregruppen mit methanolischer KOH, und dem Teilschritt H, einer vollständigen Hydrolyse der AG und Titration der Säuregruppen (SG) mit wäßriger NaOH, (ii) Methode B basierend auf der Reaktion der AG mit n-Butylamin (BA) und der Rücktitration des nicht umgesetzten Amins mit Perchlorsäure (HClO4) in Eisessig und (iii) Methode C, beruhend auf der Umsetzung der AG mit p-Chloranilin (pCA) und nachfolgender Chlorbestimmung durch Schöniger-Aufschluß. Während sich alle genannten Methoden prinzipiell für die AG-Bestimmung in Gegenwart initialer SG empfehlen, ist darüber hinaus über A/H eine simultane Bestimmung von AG und SG möglich. Wegen dieses zusätzlichen Informationsgewinns, ihrer besseren Reproduzierbarkeit, der erhöhten Richtigkeit sowie des geringeren zeitlichen und apparativen Aufwandes ist die Kombination A/H zu favorisieren. Mit Hilfe der FTIR-Spektroskopie wurde der Gehalt an AG und SG qualitativ verfolgt und eine Korrelation zwischen den Bandenintensitäten der AG und den potentiometrisch erhaltenen Werten gefunden.
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  • 65
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    Angewandte Makromolekulare Chemie 229 (1995), S. 15-27 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Härtung eines ungesättigten Polyesterharzes mit niedrigem Exotherm-Peak wurde mit der Standardmethodik und der Differential-Kalorimetrie (DSC) untersucht. Ein Kupfersalz und α-Methylstyrol wurden als Polymerisationsverzögerer benutzt. Der Einfluß der Verzögerer auf die Temperatur des exothermen Peaks, die Gelzeit, die Härtungsenthalpie und die Polymerisationskinetik wurden untersucht.
    Notes: The curing behavior of an unsaturated polyester resin with low exotherm peak was studied by a standard procedure and by differential scanning calorimetry (DSC). A copper salt and α-methylstyrene were used as the polymerization retarders. The influence of the retarders on the exotherm peak temperature, gelation time, exothermic heat and the polymerization kinetics was investigated.
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  • 66
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    Angewandte Makromolekulare Chemie 229 (1995), S. 93-112 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Propen und 1-Octen wurden mit dem syndiospezifischen Metallocen-Katalysator Me2C(Cp)(Flu)ZrCl2/MAO copolymerisiert. Es wurde ein hoher, statistischer Octeneinbau beobachtet. Niedrige Octenkonzentrationen beeinflußten die Aktivität des Katalysators nur wenig; Molekulargewicht, Kristallinität, E-Modul und Glastemperatur wurden dagegen mit ansteigendem Octengehalt erniedrigt. Blends aus ataktischem Oligopropen und syndiotaktischem Polypropen bzw. Poly(propen-co-octen) wurden aus einer Toluol-Lösung hergestellt. Diese Lösungsblends wurden mit einem Reaktorblend verglichen, der mit einem Hybrid-Katalysator bestehend aus einer Mischung von syndiospezifischem Me2C(Cp)(Flu)ZrCl2/MAO und unspezifischem Cp2ZrCl2/MAO hergestellt wurde. Das ataktische Oligopropen wirkte als Weichmacher, der E-Modul und Glastemperatur der Blends erniedrigte.
    Notes: Propene and 1-octene were copolymerized with the syndiospecific homogeneous metallocene catalyst Me2C(Cp)(Flu)ZrCl2/MAO. Large amounts of octene were incorporated randomly. While catalyst activity was not affected markedly by low octene content, molecular weight, crystallinity, Young's modulus, and glass transition temperature were reduced with increasing octene content. Blends of atactic oligopropene with syndiotactic polypropene and poly(propene-co-octene) were prepared from toluene solution and compared with a reactor blend prepared with a hybrid catalyst containing a mixture of syndiospecific Me2C(Cp)(Flu)ZrCl2/MAO and non-specific Cp2ZrCl2/MAO. Atactic oligopropene acted as plasticizer reducing Young's modulus and glass transition temperature of the blends.
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  • 67
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    Angewandte Makromolekulare Chemie 229 (1995), S. 175-184 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die innere Oberfläche und das Hohlraumsystem von verschiedenartigen Celluloseregeneratfasern werden mit Röntgenkleinwinkelstreuung untersucht. Dabei wird gefunden, daß alle Fasern ein Hohlraumsystem von 0,01 bis 0,1% (Volumenanteil 10-4-10-3) aufweisen. Es zeigt sich jedoch, daß die Größe des Hohlraumsystems für die mechanischen Eigenschaften wenig Bedeutung hat. Es ist vielmehr die Gestalt der Hohlräume und ihre Orientierung, die hier wesentlich sind. Es wird gefunden, daß langgestreckte Hohlräume, vermutlich orientiert, für gute mechanische Eigenschaften verantwortlich sind. Damit können auch verbesserte textile Eigenschaften von Lyocellfasern des NMMO-Typs erklärt werden.
    Notes: Both the inner surface and the void system of different cellulose regenerate fibers are investigated with X-ray small angle scattering. Thereby it turns out that all fibers have a void system of 0.01 to 0.1% (volume fraction 10-4-10-3). However, the amount of the void system has little influence on the mechanical properties. Rather, it is the shape of the voids and their orientation which proves essential. It is found that elongated voids, probably well oriented, are responsible for superior mechanical properties. This explains also improved textile properties of lyocell fibers of the NMMO type.
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  • 68
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    Angewandte Makromolekulare Chemie 230 (1995), S. 1-12 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die mit γ-Strahlen induzierte Polymerisation von Methacrylsäure (MA) und Acrylsäure (AA) mit Acrylamid (AAm) (M2) in Substanz wurde untersucht. Die nach Kelen-Tüdős berechneten Copolymerisationsparameter betragen r1 = 1.35 und r2 = 0.22 für MA-AAm bzw. r1 = 1.75 und r2 = 0.10 für AA-AAm. Die Polymerisationsgeschwindigkeit hängt sowohl von der Temperatur als auch von der Comonomerzusammensetzung ab. Die differentialkinetischen Kurven sind unimodal, was darauf hinweist, daß nur der Copolymerisationsprozeß abläuft. Ein zweites Maximum in diesen Kurven wird mit Vernetzung und der Bildung wasserunlöslicher Bestandteile erklärt. Die Copolymeren sind weiße Pulver; die wasserlöslichen Fraktionen sind im Gegensatz zu den wasserunlöslichen nicht giftig, aber als Immunmodulatoren weniger aktiv.
    Notes: A study was made of the γ-radiation-induced bulk copolymerization of the methacrylic acid-acrylamide (M2) (MA-AAm) and acrylic acid-acrylamide (M2) (AA-AAm) monomeric pairs. The copolymerization reactivity ratios deterined according to the Kelen-Tüdő method were: r1 = 1.35, r2 = 0.22 for the MA-AAm pair, and r1 = 1.75, r2 = 0.10 for the AA-AAm pair. It has been established that the polymerization rate depends both on the composition of the starting reaction mixture and on the reaction temperature. The differential kinetic curves obtained are unimodal ones, suggesting the occurrence of only one process, i.e. copolymerization. A second maximum in these curves, appearing at elevated temperature, is explained by crosslinking and formation of a water-insoluble fraction. The copolymers obtained are white powders; in contrast to their water-insoluble fractions, the water-soluble ones are not toxic but they are less active as immunomodulators.
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  • 69
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    Angewandte Makromolekulare Chemie 228 (1995), S. 201-219 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Hydrolyse von Poly(ester-urethan-harnstoffen) (PURUs) wurde untersucht. Es handelt sich dabei um einen komplexen Vorgang, der die Analyse der Beziehung zwischen der Zusammensetzung der PURUs und ihrer Hydrolysebeständigkeit erschwert. Es wurde gefunden, daß die Hydrolysebeständigkeit mit Zunahme (i) der Polyol-Acidität, (ii) des Estergruppen-Gehaltes, (iii) der Beweglichkeit der Hauptketten und (iv) deren Hydrophilie abnimmt; die Molmasse des Polyols scheint keinen merklichen Einfluß darauf zu haben. Der negative Einfluß von Ethergruppen (obwohl hydrolysebeständiger als Estergruppen) ist möglicherweise auf eine Zunahme der Hauptkettenbeweglichkeit und den dadurch leichteren Zugang von Wassermolekülen zu Estergruppen zurückzuführen. Der positive Effekt von aromatischen Ringen in Polyolen kann einer erhöhten Steifigkeit der Hauptkette als auch einer ansteigenden Hydrolysebeständig-keit benachbarter Estergruppen durch Resonanzeffekte zugeschrieben werden. Insgesamt kann angenommen werden, daß die beschriebenen Effekte sich überlagern und gleichzeitig die resultierende Hydrolysebeständigkeit vorherbestimmen. Es sollte daher möglich sein, qualitative Vorhersagen bezüglich der Hydrolysebeständigkeit in Abhängigkeit von der Zusammensetzung der PURUs zu treffen.
    Notes: Hydrolysis of poly(ester urethane ureas) (PURUs) is a complex phenomenon which impedes the analysis of the relationships between their composition and hydrolytic stability. Hydrolytic stability of PURUs decreases due to rising (i) polyol acidity, (ii) content of ester groups, (iii) flexibility and (iv) hydrophilicity of the backbones; molar mass of polyols does not seem to have any appreciable effect on it. Negative influence of ether groups (which have better hydrolytic stability than ester groups) is probably linked to the increase in the backbone flexibility and, consequently, to easier access of water molecules to ester groups. Positive effect of aromatic rings in polyols can be ascribed to enhanced rigidity of the backbones as well as to increased hydrolytic stability of adjacent ester groups due to the resonance effect. It can be presumed that the mentioned effects will superpose and simultaneously predestine the resulting hydrolytic resistance. Considering the observed tendencies, it is possible to qualitatively predict the trends how the hydrolytic stability will respond to changes in PURUs composition.
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  • 70
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    Angewandte Makromolekulare Chemie 229 (1995), S. 63-72 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Eine neuartige lichtempfindliche Naphthochinondiazid-Verbindung (NQD) wurde aus 2,6-Bis(hydroxymethyl)-3,4-dimethylphenol und Toluoldiisocyanat synthetisiert und mit IR-, NMR- und Elementaranalyse identifiziert. Die Bleicheigenschaften unter Lichteinwirkung wurden mit UV-Spektrophotometrie bestimmt. Die Anwendung von NQD in der Photolithographie als positiver Photoresist sowie einer wäßrigen Lösung von NQD, Novolak, Cellosolve-Acetat und DMF als lichtempfindliches Material wurde untersucht. Das hergestellte NQD erwies sich als effektive Komponente in positiven Photoresists. Die optimalen Bedingungen der UV-Dosis, Schichtdicke und Resistzusammensetzung wurden abgeschätzt. Die Auflösung des positiven Photoresists wurde durch Rasterelektronenmikroskopie bestimmt. Außerdem wurde der Einfluß von UV-Dosis und -Wellenlänge, Einwirkungsdauer und Entwicklungszeit auf die Empfindlichkeit und die Auflösung des Photoresists untersucht.
    Notes: A new photosensitive naphthoquinonediazide (NQD) was synthesized from 2,6-bis-(hydroxymethyl)-3,4-dimethylphenol and toluene diisocyante. NQD was identified by using IR, NMR and elemental analyses. Photobleachable characteristics were evaluated by UV spectrophotometry. Applications of the NQD on the photolithography as a positive working photoresist were investigated. The aqueous solution of NQD, novolak, cellosolve acetate, and DMF was used as a photosensitive material. It was found that NQD synthesized in this investigation can be used as an effective component in a positive photoresist. Optimal conditions of the UV dose, coating thickness, and development of the resist system were estimated. Resolution of the positive resist was evaluated by SEM technique. Effects of UV dose, exposure time, development time, and exposure UV wave length on the sensitivity and resolution of the photoresist were investigated.
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  • 71
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    Angewandte Makromolekulare Chemie 229 (1995), S. 123-132 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die radikalinduzierte Polymerisation von phenlysubstituierten 2-Methylen-1,3-dioxanen wurde untersucht. Es kann gezeigt werden, daß die grundlegende Polymerisationstendenz derartiger Ketenacetale darin besteht, über die Doppelbindung zu hochmolekularen Polyacetalen ohne eine nennenswerte Ringöffnung zu polymerisieren. Einflußfaktoren, wie z. B. resonanzstabilisierte Kettenenden oder sterische Hinderungen während des Wachstumsschrittes sind nicht in der Lage, die Polymerisation in die Richtung der gewünschten Ringöffnung zu lenken.Mittels Dichtemessungen wurden Informationen über das Schrumpfungsverhalten gewonnen. Es konnte gezeigt werden, daß raumerfüllende Substituenten am 2-Methylen-1,3-dioxansystem bei der Homopolymerisation grundsätzlich eine geringe Volumenschrumpfung bewirken und die Schrumpfung von herkömmlichen Monomeren bei der Copolymerisation herabsetzen können.
    Notes: We have investigated the free radical polymerization of phenyl-substituted 2-methylene-1,3-dioxanes. It was shown that there is a basic tendency of such ketenacetals to undergo exclusively a vinyl polymerization forming high-molecular polyacetals without any detectable ring opening. The polymerization with the desirable ring opening reaction cannot be controlled by factors like resonance stabilized chain ends or steric hindrance in the growing step.From densitometric measurements we got new information about the shrinkage behaviour. It was demonstrated that bulky substituents attached to the 2-methylene-1,3-dioxane system result in a significant low shrinkage in homopolymerization and the shrinkage of common comonomers can be decreased by copolymerization.
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  • 72
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    Angewandte Makromolekulare Chemie 229 (1995), S. 133-143 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Polymerisation von Acrylamid (AAM) in einer konzentrierten bikontinuierlichen Mikroemulsion wurde studiert. Die Initiierungsstelle bei Verwendung von radikalischen Initiatoren mit verschiedener Wasserlöslichkeit wurde untersucht. Es wurde festgestellt, daß ein vollständig oder teilweise wasserlöslicher radikalischer Initiator die Acrylamidpolymerisation in der untersuchten Mikroemulsion effektiv initiieren kann. Die dadurch entstandenen Polymeren weisen eine Spezialstruktur auf, die von der Zusammensetzung der ursprünglichen Mikroemulsion abhängig ist.
    Notes: The polymerization of acrylamide (AAM) in concentrated bicontinuous microemulsion systems was studied. The locus of initiation using radical initiators with various water-solubility was investigated. It was found that water-soluble and partially water-soluble initiators initiate the AAM polymerization in the reaction systems under investigation very effectively. The polymers thus formed have special structures dependent on the composition of the original concentrated bicontinuous microemulsion.
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  • 73
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    Angewandte Makromolekulare Chemie 229 (1995), S. 209-209 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 74
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    Angewandte Makromolekulare Chemie 229 (1995), S. 185-198 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Bacteriorhodopsin is a component of the purple membrane of Halobacterium halobium. It shows photochemical activity and undergoes a series of photocyclic-associated conformational changes. Incorporated in a matrix it is suitable as a light energy/electrical current transducer. Very important is an orientation of purple membrane fragments.The reaction between solutions of a polyelectrolyte and multivalent ions leads to a ionotropic gel, that is a gel with an ordered structure. If the gel formation was carried out in the presence of purple membrane fragments, the Bacteriorhodopsin is highly oriented and produces a photoelectrical signal. It consists a correlation between the light direction and the orientation of the purple membrane due to the gel formation.
    Notes: Bacteriorhodopsin ist Bestandteil der sogenannten Purpurmembran des Mikroorganismus Halobacterium halobium. Es zeigt photochemische Aktivität und kann als biologischer Lichtwandler fungieren. Voraussetzung hierfür ist eine orientierte Anordnung der Purpurmembran in einer Matrix.Das Prinzip der ionotropen Gelbildung, d. h. die geordnete Strukturbildung einer Polyelektrolytlösung infolge eines gerichteten Diffusionsstromes von mehrwertigen Ionen gestattet die orientierte Anordnung der Purpurmembran. Durch Lichteinwirkung werden elektrische Signale induziert. Es besteht ein Zusammenhang zwischen der Richtung des Strahlungseinfalls und der durch die Gelwachstumsrichtung festgelegten Orientierung der Purpurmembran.
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    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The thermal oxidation of β ray-crosslinked polyethylene (XLPE) was studied in temperatures ranging from 90 to 180°C. Various analytical methods were used for determination of an end of the induction period on bulk samples: gravimetry, ultimate tensile properties, density and color change. On microtome slices of ∼30 μm thickness the depth distribution of oxidation products, phenolic antioxidant, density and tensile ultimate properties were followed as a function of exposure time by respectively IR and UV spectrophotometry, densitometry and Microfoil Tensile Testing.Depending on the testing method different durations of induction period (DIP) were obtained. They increase in following order:Phenol depletion 〈 Ultimate elongation 〈 Density 〈 Carbonyl build-up ≤ Color change 〈 Weight loss.The difference between phenol depletion DIP and carbonyl build-up DIP can be considered as negligible at temperatures higher than the melting point (about 30%) but it reachs more than 100% at T〈 Tm.Different kinetic regimes of phenol consumption were observed depending on the exposure temperature. A mechanistic interpretation is proposed explaining the role of the stabilizer system in initially homogeneous and later heterogeneous oxidation of the bulk material.The Arrhenius law was applied to different durations of induction period. A discontinuity appeared in the melting point region (120-130°C) which is tentatively interpreted in terms of different stabilizer concentration in amorphous phase of semicrystalline material (T 〈 Tm) and in melt material (T 〉 Tm). On the basis of the presented complex study of polyethylene thermo-oxidation, different aspects of lifetime predictions are discussed.
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  • 76
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Most plastics are produced from oil and have a high potential as hydrocarbon sources for the chemical industry. Pyrolysis is a practicable way to pyrolyze mixed plastics. The fluidized bed pyrolysis has turned out to be particularly advantageous. 25 to 45 percent of product gas with a high heating value and 30 to 50 percent of an oil rich in aromatics, could be recovered. The oil is comparable to that of a mixture of light benzene and bituminous coal tar. Up to 60 percent of ethene and propene are produced by using mixed polyolefins as feedstock. Under appropriate conditions the pyrolysis could be successful on the market.
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  • 77
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: When poly(methyl methacrylate) films containing UV absorbers are exposed to UV light, the absorbers undergo photodegradation resulting in loss of absorbance. If the data extend for less than one half-life, both zero and first order kinetic treatment give fairly linear fits, but the rate constants so derived are dependent on the initial absorbance of the films. When the zero order rate constants are corrected to account for the higher rate of degradation near the surface compared with the bulk that occurs in highly absorbing films, consistent “infinite absorption” zero order rate constants are derived. The inhomogeneous degradation is due to only the highly absorbed, higher energy light contributing significantly to the degradation. For the benzophenone and benzotriazole classes of absorber, at least 65% of the degradation is due to light with wavelengths 〈 350 nm. Structural variations generally caused only small differences in the rates of degradation of these classes of absorbers unless the substitutions disrupted the intramolecular hydrogen bonds that are critical for stability. If the hydrogen bond is weakened, the absorber is less stable.
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  • 78
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Aus Cardanol, einem Bestandteil der Schale der Cashewnuß, wurde durch Kondensation mit Formaldehyd und substituierten aromatischen Verbindungen unter saurer oder basischer Katalyse eine Reihe von Harzen hergestellt und anhand ihrer IR-Spektren charakterisiert. Sie lassen sich als selektive Ionenaustauscher für bestimmte Ionen verwenden, was mittels einer Gleichgewichtsmethode geprüft wurde. Das thermische Verhalten der Harze wurde untersucht, und ein plausibler Abbaumechanismus wird vorgeschlagen.
    Notes: A large number of resins have been synthesized by reacting cardanol, a constituent of cashewnut shell liquid, with formaldehyde and substituted aromatic compounds in the presence of acidic and basic catalysts. The resins have been characterized by IR spectra. They were shown to be selective ion exchangers for certain metal ions. A batch equilibrium method was used for studying the selectivity of the metal ions. The thermal behaviour of the resins has been studied and a plausible degradation mechanism has been suggested.
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  • 79
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Bisphenol A polycarbonate (BPA-PC) is an important high performance engineering thermoplastic well known for its outstanding combination of toughness, transparency and heat resistance. These properties make it an idel material for demanding applications where it is exposed to external stresses such as elevated temperatures, ultraviolet light and γ-ray sterilization. However, on extended exposure to these conditions, BPA-PC slowly degrades, turning progressively more yellow, eventually leading to a decrease in its physical properties. Over the years, there has been numerous studies made to understand these degradative processes so as to better design more stable BPA-PC formulations. In this paper, this chemistry is briefly reviewed along with more recent work in this area with a special emphasis on the efforts made to identifying the actual chemical species responsible for the observed yellow color and the chemistry responsible for their formation.
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  • 80
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Hindered Amine Light Stabilizers (HALS) are know to inhibit the photo-oxidation of polymers. A key reaction in their stabilization mechanism is believed to be the conversion of a hindered aminoether into a nitroxyl radical. Several different possible mechanisms for this conversion were explored. One, the elimination of the aminoether to form an olefin and hydroxylamine (an intermediate in the formation of a nitroxyl), while possible at high temperatures, cannot account for the inhibitory activity we observed for secondary and primary aminoethers. Direct radical displacement by peroxy radicals was also considered. However, the products predicted by this reaction pathway were not observed. Finally, oxidation of the nitrogen by a peroxy radical, by either electron transfer or a radical attack on the nitrogen, was investigated. While electron transfer was shown to be unlikely, direct oxidation of the aminoether nitrogen was supported by our results. A detailed mechanism for the reaction of both alkyl- and acyl-peroxy radicals with aminoethers is proposed.
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  • 81
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die thermischen und dynamisch-mechanischen Eigenschaften einiger linearer kautschukelastischer Polyurethane mit chemisch unterschiedlichen starren Segmenten wurden untersucht und zur chemischen Zusammensetzung in Beziehung gesetzt. Interessante Zusammenhänge wurden zwischen der Kristallinität der elastischen Polyurethanharnstoffe und der aromatischen oder cycloaliphatischen Natur der Diisocyanat-Komponenten gefunden. Darüber hinaus scheinen die Ergebnisse bei einem bestimmten Verhältnis zwischen starren und flexiblen Segmenten und bei gegebener Zusammensetzung der flexiblen Gruppen auf eine bessere Phasenseparation bei den Polyurethanharnstoffen mit cycloaliphatischen starren Segmenten als bei solchen mit aromatischen, starren Einheiten hinzuweisen.
    Notes: Experimental batches of linear rubber-like polyurethanes characterized by the presence of chemically different hard segments are studied and their thermal and dynamic-mechanical properties are related to the differences in chemical compositions. Interesting correlations are found between the development of crystallinity in such elastomeric poly(urethaneurea)s and the aromatic or alicyclic nature of the diisocyanate. Moreover, for a fixed ratio between hard and soft segments, and for a given composition of the soft segment, the results seem to indicate a better degree of phase separation in cycloaliphatic-based hard segment poly(urethaneurea)s than in aromatic-based hard segment poly(urethaneurea)s.
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  • 82
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    Angewandte Makromolekulare Chemie 231 (1995), S. 135-144 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Makromonomere Polyethylenoxid-Azoinitiatoren (Makroinimere) MIM-400 und MIM-1500 wurden synthetisiert und IR- und NMR-spektroskopisch sowie mit Hilfe der DSC-Analyse charakterisiert. Die mit diesen Makroinimeren initiierte Dispersions-polymerisation von Styrol bzw. Methylmethacrylat (MMA) in Ethanol/Wasser bei 60°C wurde untersucht. Dabei wurde gefunden, daß die Polymerisationsgeschwindig-keit mit zunehmender MIM-Konzentration ansteigt, wobei der Anstieg im Styrolsystem ausgeprägter war. Im Bereich von mittleren Umsätzen konnte gezeigt werden, daß die Polymerisationsgeschwindigkeit von MMA proportional der Potenz 1,7 bzw. 1,6 von [MIM-400] bzw. [MIM-1500] ist, während für Styrol eine Potenz von 2,5 bezüglich [MIM-400] gefunden wurde.
    Notes: Macromonomeric poly(oxyethylene) azoinitiators (macroinimers) MIM-400 and MIM-1500 were synthesized and characterized by IR and NMR spectroscopy and DSC techniques. The dispersion polymerizations of styrene and methyl methacrylate (MMA) initiated by poly(oxyethylene) macroinimers (MIM-400 and MIM-1500) in water/ethanol were investigated at 60°C. The rate of polymerization was found to increase with increasing concentration of MIM and the increase was more pronounced in the styrene system. In the range of medium conversions the rate of polymerization was found to be proportional to the 1.7th and 1.6th power of [MIM-400] and [MIM-1500] for MMA and to the 2.5th power of [MIM-400] for styrene, respectively.
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  • 83
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    Angewandte Makromolekulare Chemie 231 (1995), S. 187-198 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Glass transition temperatures of binary and ternary blends of chemically uniform poly(styrene-co-n-butyl methacrylate)s with a mean content of 30.8 wt.-% of n-butyl methacrylate and number-average molar masses in the range of 4900 and 67000 g/mol have been investigated in relation to their composition. The blends showed significant deviations from an ideal behaviour with reference to a linearity between glass transition temperature and composition.This phenomenon is described by a mathematical model where polynoms are particularly well suited to represent the glass transition temperatures of the blends, partly exceeding those of the pure components. Finally, various reasons of these deviations were discussed. Here, energetical interactions seem to be of considerable importance combined with a nonadditivity of volumes.
    Notes: Die Glasübergangstemperaturen binärer und ternärer Mischungen chemisch einheitlicher Poly(styrol-co-n-butylmethacrylat)e mit einem mittleren n-Butylmethacrylat-Anteil von 30,8 Gew.-% und unterschiedlichen zahlenmittleren Molmassen im Bereich von 4900 bis 67000 g/mol wurden in Abhängigkeit von der Zusammensetzung untersucht. Es wurden wesentliche Abweichungen vom idealen Verhalten bezüglich einer linearen Abhängigkeit zwischen Glasübergangstemperatur und Zusammensetzung festgestellt.Dieses Verhalten konnte mit einem mathematischen Modell dargestellt werden, wobei sich insbesondere Polynome zur Beschreibung der teilweise über den Werten der Ausgangskomponenten liegenden Glasübergangstemperaturen der Mischungen als geeignet erwiesen. Schließlich wurden verschiedene Ursachen für diese Abweichungen diskutiert, wobei offensichtlich energetische Wechselwirkungen verbunden mit einer Nichtadditivität der Volumina von wesentlicher Bedeutung sind.
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  • 84
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    Angewandte Makromolekulare Chemie 233 (1995), S. 133-148 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: ε-Caprolactam (CL) and phenyl glycidyl ether (PGE) were homopolymerized using the initiator/accelerator-systems Na-caprolactam/N-acetyl-caprolactam (NaCL/AcCL) and Na-caprolactam/N-acetyl imidazole (NaCL/AcImi). In a one-pot reaction both monomers gave different oligomeric reaction products depending on the reaction temperature (100°C to 140°C, max. 240°C) but no regular copolymers. Soluble products were separated by HPLC and identified by means of spectroscopic methods. In acetone insoluble products were investigated by IR- and NMR-spectroscopy, mass spectrometry and elemental analysis.
    Notes: Es wurden Versuche zur Homopolymerisation von ε-Caprolactam (CL) und Phenylglycidether (PGE) mit den Initiator/Beschleuniger-Systemen Na-Caprolactam/N-Acetylcaprolactam (NaCL/AcCL) und Na-Caprolactam/N-Acetylimidazol (NaCL/AcImi) durchgeführt, um die für eine mögliche Copolymerisation von CL und PGE geeigneten Reaktionsbedingungen zu ermitteln. CL und PGE wurden in unterschiedlichen molaren Verhältnissen (CL : PGE = 1 : 5 bis 1 : 0,05) und bei Temperaturen zwischen 100°C und 140°C (max. 240°C) in einer Eintopfreaktion polymerisiert.Die löslichen Produkte wurden mittels HPLC getrennt und spektroskopisch identifiziert. Die in Aceton unlöslichen Produkte wurden mit IR- und NMR-Spektroskopie, Massenspektrometrie (MS) und Elementaranalyse untersucht.
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  • 85
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    Angewandte Makromolekulare Chemie 236 (1996), S. 111-127 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Neuartige Fluoropolyether-Polyol-Harze, die mit konventionellen Härtern wie Polyisocyanaten oder Melaminen aushärtbar sind, wurden hergestellt. Zunächst wurden oligomere NCO-terminierte Prepolymere durch Addition von Fluorpolyether-Makrodiolen unterschiedlicher Molekulargewichte an Isophorondiisocyanate erhalten. Durch die Reaktion dieser Prepolymeren mit Trimethylolpropan wurden endständige Hydroxygruppen eingeführt. Die Viskosität von Lösungen dieser Harze wurde bei unterschiedlichen Konzentrationen (Massenbruch 0,4-0,8) und Temperaturen (25°C-65°C) gemessen. Die erhaltenen Werte wurden auf der Basis der Erickson-Gleichung (Konzentrationsabhängigkeit von η) und unter Berücksichtigung des WLF-und des Arrhenius-Modells (Temperaturabhängigkeit von η) diskutiert. Das thermische Verhalten der Harze und von ausgehärteten Filmen wurde mit DSC bestimmt. Dabei wurden zwei Glasübergange beobachtet, die den separierten fluorhaltigen und nicht-fluorhaltigen Phasen zugeordnet werden können. Die Analyse des Zugverhaltens der Filme zeigte besonders bei den mit Isocyanat gehärteten Proben ein ausgeprägtes hart-plastisches Verhalten. Diese Werkstoffe erscheinen für die Anwendung als hoch-wertige, dauerfeste und klare Beschichtungen geeignet.
    Notes: New fluoropolyether polyolic resins are presented suitable to be cured with conventional hardeners as polyisocyanates or melamines. These resins are prepared by addition of fluoropolyether macrodiols (Fomblin® ZDOLTX) of various molecular weights to isophorone diisocyanate (IPDI) to give oligomeric NCO-terminated prepolymers. The final hydroxy functionality is obtained by the reaction of those prepolymers with trimethylolpropane (TMP). The viscosity of the resins is measured at various concentrations (weight fraction 0.8 - 0.4) and temperatures (T = 25-65°C). The results are discussed in terms of the Erickson equation (η vs. concentration) and using the WLF and Arrhenius models (η vs. T). The thermal behavior is studied by DSC for both the resins and cured films indicating the presence of two Tgs, corresponding to the segregated fluorinated and hydrogenated phases, the former particularly evident with the highest molecular weights of the fluorinated macromer. Tensile curves of selfsupported films are then analyzed showing an evident tough-plastic behavior especially for the isocyanate-cured films. The application of such materials as high-durability clear coats is finally proposed.
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  • 86
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    Angewandte Makromolekulare Chemie 237 (1996), S. 1-44 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Zur Verbesserung der Maßhaltigkeit und der Zähigkeit von gehärteten Melamin-Formaldehyd-Harz-Formmassen (MF) wurden teilverträgliche, methylolgruppenhaltige Epoxidharze (EP) auf Bisphenol A-Basis hergestellt und charakterisiert. Die Vernetzung solcher Epoxyresolharze durch 2-Ethyl-4-methylimidazol in Gegenwart von MF-Harz wurde untersucht. Spritzgepreßte Probekörper zeigen eine Zweiphasenstruktur; die EP-Phase kann als Wirt für carboxy-funktionalisierte, oligomere NBR-Kautschuke (CTBNX) dienen, die für sich allein in MF-Harzen nicht wirksam sind. Unter der Voraussetzung von kovalenten Bindungen in der Phasengrenzfläche kann durch den Zusatz von 0,5 bis 4 Gew.-% CTBNX zur MF-Formmasse bei EP-Anteilen bis 20 Gew.-% eine 50 bis 100proz. Steigerung von Bruchdehnung und Schlagzähigkeit erreicht werden, ohne daß Steifigkeit und Wärmeformbeständigkeit wesentlich abfallen. Bei moderaten EP/CTBNX-Gehalten wird zusätzlich die Nachschwindung von MF-Formteilen vermindert.
    Notes: In order to improve dimension stability and toughness of melamine formaldehyde moulding materials (MF), compatible bisphenol A epoxy resins (EP) with additional methylol groups were synthesized and characterized. Crosslinking of those epoxyresol resins with 2-ethyl-4-methylimidazole in the presence of MF resin was investigated. Transfer-moulded specimens revealed a two-phase morphology in which the EP phase is used as a host for modification with carboxylic functionalized oligomeric NBR rubber (CTBNX), which is not effective in MF moulding materials alone. The addition of 0.5 - 4 wt.-% CTBNX to the MF moulding materials at an epoxy content of maximum 20 wt.-% results in 50-100 % increase of elasticity and toughness without serious decrease in stiffness and heat deflection temperature, provided that covalent interfacial bonds exist. In addition, the post-shrinkage of MF parts decreases if a moderate EP/CTBNX content is introduced.
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  • 87
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    Angewandte Makromolekulare Chemie 238 (1996), S. 11-30 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Der gleichzeitige Einfluß des Verhältnisses von Fließhilfsmittel (Paraloid K 120N), Rußart und Schlagzähmodifikator (CPE 3615 und Kane Ace B56 A) auf die wichtigsten physiko-mechanischen Eigenschaften unplastifizierter PVC-Mischungen wurde studiert.Die erhaltenen Resultate wurden mathematisch verarbeitet und graphisch als Funktionsflächen dargestellt. Bemerkenswert ist, daß die Einführung von 2,5 und 5 Teilen Ruß eine Verbesserung der physico-mechanischen Eigenschaften ermöglicht. Dieses Resultat ist durch die Anwesenheit der Schlagzäh- und Fließmodifikatoren zu erklären.
    Notes: The concurrent influence of the processing aid (Paraloid K 120N) and the carbon black ratio, as well as the nature and the ratio of the impact modifier (CPE 3615 and Kane Ace B56 A) on the main physico-mechanical characteristics of the poly(vinyl chloride)-based unplasticized mixtures have been studied. The results obtained, processed mathematically and plotted graphically in the form of response surfaces, evidenced that the improvement of certain physico-mechanical properties becomes possible by the introduction of 2.5 parts and 5.0 parts carbon black into these compounds. This is due to the introduction of impact modifiers and processing aids into the mixtures.
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  • 88
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    Angewandte Makromolekulare Chemie 238 (1996), S. 63-71 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Eine Reihe neuartiger Polyhydrazide mit endständigen Phenoxygruppen wurde aus äquimolaren Anteilen von Dicarbonsäuredichloriden und Phenoxyterephthalsäuredihydrazid durch Lösungspolykondensation in N-Methyl-2-pyrrolidinon (NMP) bei niedriger Temperatur hergestellt. Durch thermische Cyclisierung der Polyhydrazide wurden die entsprehchenden Poly(1,3,4-oxadiazol)e mit endständigen Phenoxygruppen erhalten. Die Polymeren wurden durch Viskosimetrie, Löslichkeitsuntersuchungen, IR-Spektroskopie, Differentialkalorimetrie und Thermogravimetrie charakterisiert.
    Notes: A series of new polyhydrazides containing pendent phenoxy groups has been synthesized by low-temperature solution polycondensation of equimolar amounts of diacid dichlorides and 2-phenoxyterephthalic dihydrazide in N-methyl-2-pyrrolidi-none (NMP). The thermal cyclization of the polyhydrazides gave the corresponding poly(1,3,4-oxadiazole)s containing pendent phenoxy groups. The polymers were characterized by viscometry, solubility measurements, IR spectroscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis.
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  • 89
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    Angewandte Makromolekulare Chemie 238 (1996), S. 105-117 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Ein Ethylen-Vinylacetat-Copolymeres (EVA) mit 12% Vinylacetat-Gehalt wurde mit Trimethylolpropantrimethacrylat (TMPTMA) als Sensibilisator mit Elektronen bestrahlt. Die mechanischen und elektrischen Eigenschaften der bestrahlten Copolymerproben wurden untersucht. Die Resultate zeigen, daß sich Zugfestigkeit und Bruchdehnung zunächst mit zunehmender Strahlungsdosis verbessern und bei Überschreiten einer optimalen Strahlungsdosis und Sensibilisatorkonzentration wieder verschlechtern. Durch die Bestrahlung wird eine Vernetzung des Polymeren ausgelöst, die auf den sich mit der Strahlungsdosis erhöhenden Gelanteil zurückgeführt wird. Im Vergleich mit den Originalproben nehmen sowohl die Dielektrizitätskonstante als auch der dielektrische Verlustfaktor durch die Elektronenbestrahlung ab.
    Notes: Ethylene-vinyl acetate (EVA) copolymer (12% vinyl acetate content) is subjected to electron beam irradiation using trimethylolpropane trimethacrylate (TMPTMA) as a radiation sensitizer. Mechanical and electrical studies of these irradiated samples show that the strength properties (tensile strength, elongation at break) are increased with radiation dosage up to an optimum radiation dose and sensitizer level above which the properties begin to deteriorate. Crosslinking of the polymer takes place on irradiation which is attributed to an increased gel content with increasing radiation dose. Compared to the original samples both dielectric constant and dielectric loss factor decrease for samples subjected to irradiation.
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  • 90
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    Angewandte Makromolekulare Chemie 238 (1996), S. 143-163 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Cellulose-p-toluolsulfonsäureester (Cellulosetosylate) lassen sich durch homogene Umsetzung von Cellulose in einer Lösung aus N,N-Dimethylacetamid und LiCl mit Tosylchlorid (Tos-Cl) und Triethylamin in 24 h bei 8°C in hoher Ausbeute und mit minimalem Einbau von Chlordesoxy-Gruppen herstellen. Die unterschiedlichen Celluloseausgangsmaterialien hatten durchschnittliche Polymerisationsgrade von 280 bis 5100. Die Produkte wurden mit Elementaranalyse, 13C-NMR- und FTIR-Spektroskopie und durch Bestimmung der Grenzviskositäten charakterisiert. Die Erhöhung des Molverhältnisses Tos-Cl/Anhydroglucose-Einheit (AGU) von 0.6 auf 9.0 führte zu einem Anstieg des Substitutionsgrades (DS) von 0.4 bis auf einen Maximalwert von 2.3. Die Cellulosetosylate sind in herkömmlichen organischen Lösungsmitteln wie Dimethylsulfoxid (im gesamten DS Bereich) und in N,N-Dimethylacetamid, N,N-Dimethylformamid, Aceton, Tetrahydrofuran und Trichlormethan (in Abhängigkeit von DS) löslich. Durch 13C-NMR-Spektroskopie wurde nachgewiesen, daß die Tosylierung am O-6 Atom der AGU schneller als an den O-2/3 Atomen erfolgt. Die Analyse der korrespondierenden Ioddesoxycellulosen, die durch Umsetzung mit NaI in Acetylaceton synthetisiert wurden, bestätigte dies zusätzlich. Darüber hinaus wurden wichtige Eigenschaften der Cellulosetosylate wie die Stabilität gegenüber Alkali und thermischer Beanspruchung untersucht.
    Notes: Pure cellulose p-toluenesulfonates (tosylates) with an insignificant formation of chlorodeoxy groups were prepared by reacting cellulose dissolved in a solution of N,N-dimethylacetamide and LiCI with tosylchloride (Tos-CI) in the presence of triethylamine within 24 h at 8°C. Various cellulosic starting materials with a degree of polymerization from 280 to 5 100 were used. The samples obtained were characterized by means of elemental analysis, FTIR and 13C NMR spectroscopy, and their intrinsic viscosities. The rise of the molar ratio of Tos-CI/anhydroglucose unit (AGU) from 0.6 to 9.0 leads to an increase in the degree of substitution (DS) from 0.4 up to a maximum value of 2.3. The cellulose tosylates are readily soluble in common organic solvents like dimethyl sulfoxide (within the whole DS range) and in N,N-dimethylacetamide, N,N-dimethylformamide, acetone, tetrahydrofuran and trichloromethane depending on DS. As revealed by 13C NMR spectroscopy a faster tosylation takes place at the O-6 atom of AGU compared with the O-2/3 atoms. This was additionally confirmed by analysis of the corresponding iododeoxy celluloses synthesized with NaI in acetylacetone. Furthermore, some important properties as stability against alkaline and heat were studied as well.
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  • 91
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    Angewandte Makromolekulare Chemie 239 (1996), S. 27-32 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Herstellung einer SiC-Oberfläche auf Kohlefasern unter Verwendung einer Sol-Gel-Mischung von Tetraethylorthosilikat (TEOS) und Phenolharz wurde untersucht. FTIR- und SEM-Untersuchungen zeigten, daß die SiC-Oberfläche durch carbothermische Reduktion der Sol-Gel-Mischung bei 1 420°C innerhalb von 15-20 min in einer Argon-Atmosphäre gebildet werden kann. Mittels TGA konnte gezeigt werden, daß die SiC-Beschichtung die thermo-oxidative Stabilität der Kohlefasern erhöht. Bei der erreichten SiC-Schichtdicke von 0,47 μm, bei einem C/Si-Verhältnis von 4, zeigt sich keine Beeinflussung der mechanischen Stabilität der Kohlefasern.
    Notes: The preparation of a SiC coating on a carbon fiber surface using a sol-gel mixture of tetraethyl orthosilicat (TEOS) and phenolic resin was studied. FTIR and SEM investigations indicated that the SiC coating can be formed by carbothermal reduction of the sol-gel mixture at 1420°C for 15-20 min in an argon atmosphere. TGA of the coated fiber was also performed, showing that the SiC coating improves the thermooxidative stability of the carbon fiber. With the thickness of the obtained coating of 0.47 μm using a C/Si ratio of 4, this treatment does not affect the carbon fiber strength.
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    Angewandte Makromolekulare Chemie 239 (1996), S. 55-62 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Diese Mitteilung behandelt den Einfluß von oligomeren Polypropylen- und Polybutylenölen mit unterschiedlichem Molekulargewicht auf die adhäsiven Eigenschaften von ataktischem Polypropylen (aPP) und dessen Mischungen mit einem Styrol-Ethylhexylacrylat-Copolymeren. Die mechanische Adhäsionsarbeit Am von Mischungen, die ataktisches Polypropylen und das Oligomere enthalten, steigt mit dem Molekulargewicht des Oligomeren, was im Fall des Propylenöls signifikanter ist. Im Fall der ternären Mischungen des ataktischen Polypropylens mit dem Styrol-Ethylhexylacrylat-Copolymeren und Oligomeren wird ein Adhäsions-Maximum beobachtet, wenn der Gehalt an Styrol-Ethylhexylacrylat-Copolymeren in der Mischung ungefähr 30 Gew.-% erreicht. Wenn kein Oligomeres in der Mischung vorhanden ist, kann man bei dieser Zusammensetzung ein Adhäsions-Minimum beobachten, was auf die Unverträglichkeit der übrigen Komponenten zurückzuführen ist.
    Notes: This paper deals with the influence of oligomers, namely propylene oil and butylene oil, of different molecular weight on the adhesive properties of atactic polypropylene (aPP) and its mixtures with styrene-2-ethylhexyl acrylate (S-EHA) copolymer. The mechanical work of adhesion Am of the mixture containing atactic polypropylene and oligomer increases with the molecular weight of the oligomer, which was more significant in the case of propylene oil. For ternary mixtures aPP-S-EHA copolymer/oligomer a maximum of adhesion can be observed if the content of the S-EHA copolymer in the mixture reaches about 30 mass-%. In the absence of oligomers in the mixture a minimum of adhesion can be observed for this composition, which can be attributed to the incompatibility of the remaining components.
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  • 93
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: After comparison of three catalyst systems, i.e. [Nd(Oct)3/Al2Cl3ET3/Al(i-But)3, Ni(Oct)2/BF3OEt2/AlEt3 and Al(i-But)3/I2/TiCl4] the titanium catalyst system was used for the copolymerization of 1,3-butadiene with propylene oxide. The effects of monomer ratio on copolymer composition, conversion, microstructure, molar mass and molar mass distribution as well as of time of polymerization and of the aluminium/titanium ratio were evaluted. The copolymerization parameters were determined according to Kelen-Tüdős as rbutadiene = 0,9 and rpropylene oxide = 3,9. Copolymerization was confirmed by 13C NMR spectroscopy and extract evaluation combined with 1H NMR spectroscopy.
    Notes: Für die Copolymerisation von 1,3-Butadien mit Propylenoxid wurde nach dem Vergleich der drei Katalysatorsysteme Nd(Oct)3/Al2Cl3ET3/Al(i-But)3, Ni(Oct)2/ BF3OEt2/AlEt3 und Al(i-But)3/I2/TiCl4 das Titankatalysatorsystem eingesetzt. Neben dem Einfluß der Monomerzusammensetzung auf den Umsatz, die Microstruktur, die Copolymerzusammensetzung, die Molmassen sowie die Molmassenverteilungen wurden auch die Polymerisationszeit und das Aluminium/Titan-Verhältnis untersucht. Die Copolymerisationsparameter wurden nach Kelen-Tüdős zu rButadien = 0,9 und rPropylenoxid = 3,9 bestimmt. Der Copolymernachweis erfolgte über 13C-NMR-Spektroskopie und Extraktionsuntersuchungen in Verbindung mit 1H-NMR-Spektroskopie.
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  • 94
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 239 (1996), S. 191-199 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Phosphorhaltige Polyurethane (PU-P) auf der Basis von Bisphenol A wurden durch N-Alkylierung hergestellt und mittels IR- und 1H NMR-Spektroskopie charakterisiert. Physikalische und thermische Eigenschaften dieser Polyurethane wurden mittels Differentialkalorimetrie, Thermogravimetrie, Röntgenbeugung und Untersuchungen der Löslichkeit, der Feuerbeständigkeit (Sauerstoffindex, LOI) und der reduzierten Viskosität bestimmt. Die Glastemperaturen der N-alkylierten Polymeren sanken von 120°C für das Ausgangspolymere bis auf 29°C für das N-alkylierte Polyurethan mit 2 Gew.-% Phosphor. Die Viskosität der N-alkylierten Polyurethane nahm von 0,36 dL g-1 auf 0,24 dL g-1 ab. Die phosphorhaltigen Polyurethane besitzen eine geringere thermische Stabilität und bessere Löslichkeit sowie höhere Feuerbeständlgkeit als das Ausgangspolymere. Die Röntgenstreuexperimente ergaben, daß ein erhöhter Phosphorgehalt der Polyurethane die Kristallinität herabsetzt.
    Notes: Phosporus-containing polyurethanes (PU-P) based on bisphenol A were prepared by N-alkylation. The structures of N-alkylated polyurethanes were characterized by IR and 1H NMR spectra. Physical and thermal properties of the phosphorus-containing polyurethanes were investigated with differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction, tests of solubility, limiting oxygen index (LOI) and reduced viscosity. Tg of the N-alkylated polymers decreased from 120°C for the starting polymer to 29°C of the 2.0 wt.-% phosphorus-containing polyurethanes. The viscosity of N-alkylated polyurethanes also decreased from 0.36 dL g-1 to 0.24 dL g-1. The thermal stability of polyurethanes decreased on the introduction of phosphorus groups. The LOI values of polyurethanes showed that fire resistance of phosphorus-containing polyurethanes was enhanced. X-ray diffraction measurements showed that the increased phosphorus content was accompanied by decreased crystallinity of the polyurethanes. The solubility of PU-P was improved.
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  • 95
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: This question was addressed using various methods to monitor the process of curing and state of the final network. Attention was particularly focused on the possible inhomogeneous network formation as a consequence of the crosslinking process. An analysis of experimental data has revealed that some cured resins can be considered as homogeneous as the corresponding uncrosslinked materials. Resins cured by simple stepwise alternating chemistries, with good compatibility of components, usually fulfill the criterion of homogeneity. A family of epoxy resins cured with polyamines belongs to this category. Nodular structures seen by electron microscopy are a result of interaction of the electron beam or etching. Such structures are also observed for uncrosslinked polymers investigated under the same conditions. Formation of inhomogeneities in a number of thermoset systems is due to (a) chainwise mechanism of network formation with fast propagation inducing cyclization and steric volume exclusion and (b) poor compatibility of components of the system made stronger by increasing molecular weights and crosslinking during curing. Networks formed by freeradical polymerization and copolymerization of polyvinyl monomers can serve as an example of crosslinking-driven formation of inhomogeneities.
    Additional Material: 7 Ill.
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  • 96
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The base and transition metal catalyzed isomerization of allyl and crotyl ethers affords a facile, high yield route to the preparation of a variety of mono-, di-, and multifunctional 1-propenyl and 1-butenyl ethers. Employing this novel method, monomers containing epoxide, ester, ether carbonate and urethane groups can be prepared from their readily available allyl and crotyl precursors. In general, these monomers display very high reactivity in cationic polymerizations. In our work, we have focused on photoinduced cationic polymerizations of these monomers using diaryliodonium and triarylsulfonium salt photoinitiators. To study these very fast photopolymerizations, extensive use of real-time infrared spectroscopy was made. Employing this technique, the effects of monomer and photoinitiator structure on the rates of polymerization were studied.
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  • 97
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 240 (1996), S. 137-149 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Rubber elasticity is associated with changes in configurational entropy of a long chain. Because the chain cannot change its configuration instantaneously, there is a time delay in deformation to an applied force. This delayed response is the source of viscoelasticity and hysteresis energy loss of elastomer networks. Many tire performance properties are related to the viscoelasticity of tire components. Wet and dry traction of tire is related to the energy loss of the tread material at very high frequencies. On the other hand, rolling resistance of tire is characterized by the energy loss of tread material at relatively low frequencies. The dynamic viscoelastic properties of elastomer network shows characteristic zones on a frequency scale. At very high frequencies the energy loss is controlled by the segmental motions of the polymer chain. At lower frequencies the energy loss is related to the longer range motions of the chain. A series of polymers was synthesized to study the effect of micro- and macro-structure of the polymer on the viscoelastic properties of tread compounds and their tire performance properties. As expected from the theory, the wet traction of the tire was highly correlated to the segmental motions of the chains; namely, the glass transition temperature of the polymer. The energy loss of the compounds at a higher temperature, however, was related to the macrostructure of the polymer chain. Those examples illustrate that the fundamental understanding of the theory of elastomer network allows a tire engineer to obtain the best balance of tire performance characteristics.
    Additional Material: 7 Ill.
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  • 98
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 240 (1996), S. 171-180 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Cationic, anionic, and radical ring-opening polymerization of spiro and bicyclic monomers, and their application to network polymers have been developed. Bicyclo orthoesters (BOEs), spiro orthoesters (SOEs), and spiro orthocarbonates (SOCs) were polymerized by cationic double ring-opening. Bicyclobis(γ-butyrolactone)s and spirobis(γ-butyrolactone)s were copolymerized with epoxides by anionic alternating ring-opening. Polymers from SOCs bearing exomethylene groups consisted of ring-opened and vinyl polymerized units. The degree of ring-opening of SOCs depended upon the number of rings and steric hindrance. The radical polymerization of vinylcyclopropanone cyclic acetals depended on the ring-size. With the monomers bearing 5- and 6-membered acetal rings, single ring-opened polymers were obtained. With the monomer bearing 7-membered acetal ring, the polymer mainly consisted of double ring-opened unit. These monomers could be crosslinked by bifunctionalization. Poly(cyclic orthoester)s linked by covalent bonds with dithiols to bifunctional SOEs were crosslinked by acid catalysts, and the reversible crosslinking-depolymerization system could be controlled by temperature.
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  • 99
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 240 (1996), S. 205-211 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polyester urethane network elastomers with incorporated hard segment oligomers have been prepared by poly(ethylene adipate)glycol (PEA), 2,4-tolylene diisocyanate (TDI), and 1,4-butanediol (BD). These hard segment oligomers were hydroxy-terminated oligomers ([BD-TDI]n-BD; n=1,3), obtained by reacting BD with TDI. Concentrations of allophanate as a cross-linking site were determined by the amine degradation method. Hard segment moieties were obtained by a novel selective hydrolysis of soft segments in the elastomers. Molecular weight distributions of hard segment were measured by means of GPC. Mechanical and thermal properties were measured. Dependence of rubber elasticity on physical cross-linking between normal elastomers and the elastomers with incorporated hard segment oligomers were discussed.
    Additional Material: 5 Ill.
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  • 100
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Poly (vinyl alcohol) with pendent styrylpyridinium groups (SbQ) is insolubilized by photoirradiation. An association takes place in SbQ groups. The association of polymer chains becomes marked with increasing the number of SbQ groups. Mainly intermolecular crosslinks were formed. Transparent and homogeneous macrogels consisting of several intermolecular crosslinks are obtained.The proportion of the free water to the bound water in PVA-SbQ gels was 3.3-2.9 despite of the large change in conversion of photodimerization of SbQ groups, x=0.27-0.58. The water uptake after swelling of the gels in water increased 6-27 times compared to the original weight at pH=7. The higher the degree of photocrosslinking, the lower was the degree of swelling. The water diffusion coefficients, D, were (2.2-5.8) × 10-5 cm2 S-1 for a 88% saponified PVA with 1 . 3 mol% SbQ groups. The volume of the gel increased discontinuously about 10-fold for the 99% saponified PVA with 0 . 096 mol% SbQ and 51% water (49% acetone). The acetone concentration at the transition decreased with increasing the degree of saponification of the PVA.
    Additional Material: 10 Ill.
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