ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Polymer and Materials Science  (23,213)
  • 550 - Earth sciences  (8,764)
  • Chemical Engineering  (3,085)
  • Engineering  (3,051)
  • United States
  • 2005-2009  (7,571)
  • 1995-1999  (22,867)
  • 1965-1969  (9,698)
Collection
Keywords
Language
Years
Year
  • 1
    Unknown
    Berlin, Heidelberg : Springer
    Keywords: Crystallography ; Engineering ; Particles (Nuclear physics) ; Surfaces (Physics)
    Edition: Third Edition
    ISBN: 9783540738862
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Keywords: Condensed matter ; Engineering ; Engineering design ; Materials ; Physics
    ISBN: 9780387345659
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Keywords: Electromagnetism ; Engineering ; Laser physics ; Remote sensing
    ISBN: 9781402065033
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Keywords: Chemistry, Physical organic ; Chemistry, inorganic ; Condensed matter ; Engineering ; Materials ; Structural control (Engineering)
    ISBN: 9781402034718
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Unknown
    Berlin, Heidelberg : Springer
    Keywords: Chemistry, Physical organic ; Condensed matter ; Engineering ; Optical materials
    ISBN: 9783540712954
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Unknown
    Berlin, Heidelberg : Springer
    Keywords: Condensed matter ; Engineering ; Nanotechnology
    ISBN: 9783540726753
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Keywords: Engineering ; Materials ; Materials ; Materials ; Mechanics ; Nuclear engineering
    ISBN: 9781402053290
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Unknown
    Berlin, Heidelberg : Springer
    Keywords: Chemistry, inorganic ; Condensed matter ; Engineering ; Nanotechnology ; Surfaces (Physics)
    ISBN: 9783540368076
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Unknown
    Berlin, Heidelberg : Springer
    Keywords: Engineering ; Optical materials ; Particles (Nuclear physics) ; Physical optics
    ISBN: 9783540745297
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Keywords: Engineering ; Optical materials ; Particles (Nuclear physics) ; Physical optics ; Polymers
    ISBN: 9783540719236
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Keywords: Condensed matter ; Engineering ; Materials ; Nanotechnology ; Optical materials
    ISBN: 9781402035623
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Keywords: Engineering ; Laser physics ; Microwaves ; Optical materials ; Physical optics
    ISBN: 9780387686172
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Unknown
    Boston, MA : Springer
    Keywords: Engineering ; Machinery ; Materials
    ISBN: 9780387725284
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Unknown
    Berlin, Heidelberg : Springer
    Keywords: Chemistry ; Mathematics ; Engineering ; Operations research ; Systems theory
    ISBN: 9783540488804
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Unknown
    Boston, MA : Springer US
    Keywords: Chemistry ; Engineering ; Materials ; Mechanical engineering ; Surfaces (Physics)
    ISBN: 9780387476858
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Keywords: Condensed matter ; Engineering ; Optical materials
    ISBN: 9783540734567
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Keywords: Engineering ; Optical materials ; Physical optics
    ISBN: 9781402084256
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Unknown
    Berlin, Heidelberg : Springer
    Keywords: Analytical biochemistry ; Chemistry ; Chemistry, Physical organic ; Engineering
    ISBN: 9783540745983
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Unknown
    Boston, MA : Kluwer Academic Publishers
    Keywords: Engineering ; Materials
    ISBN: 9781402081330
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    Unknown
    Berlin, Heidelberg : Springer
    Keywords: Condensed matter ; Engineering ; Nanotechnology
    ISBN: 9783540375784
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Unknown
    Berlin, Heidelberg : Springer
    Keywords: Condensed matter ; Engineering ; Materials ; Nanotechnology ; Optical materials
    ISBN: 9783540401865
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Unknown
    Berlin, Heidelberg : Springer
    Keywords: Chemistry, Physical organic ; Engineering ; Nanotechnology ; Surfaces (Physics)
    ISBN: 9783540745518
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Unknown
    Dordrecht : Springer
    Keywords: Chemicals ; Safety measures ; Engineering ; Materials ; Polymers
    ISBN: 9781402053566
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Unknown
    New York, NY : Springer
    Keywords: Engineering ; Optical materials ; Physical optics
    ISBN: 9780387748016
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Unknown
    Berlin, Heidelberg : Springer
    Keywords: Electronics ; Engineering ; Nanotechnology
    ISBN: 9783540283089
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Keywords: Engineering ; Materials
    ISBN: 9781402085840
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Keywords: Building construction ; Engineering ; Materials ; Physics
    ISBN: 9781852334277
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    Keywords: Biochemistry ; Chemistry, Physical organic ; Engineering ; Life sciences ; Nanotechnology ; Physical optics
    ISBN: 9783540284727
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Unknown
    Berlin, Heidelberg : Springer
    Keywords: Analytical biochemistry ; Biotechnology ; Engineering ; Food science ; Medical laboratories
    ISBN: 9783540457435
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Keywords: Chemistry, Physical organic ; Engineering ; Nanotechnology ; Optical materials ; Physics
    ISBN: 9783540687528
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    Unknown
    Berlin, Heidelberg : Springer
    Keywords: Condensed matter ; Engineering ; Optical materials ; Surfaces (Physics)
    ISBN: 9783540264620
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    Unknown
    Berlin, Heidelberg : Springer
    Keywords: Engineering ; Nanotechnology ; Particles (Nuclear physics)
    ISBN: 9783540745570
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Keywords: Chemistry ; Engineering ; Magnetism ; Materials ; Optical materials
    ISBN: 9781402087967
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Keywords: Condensed matter ; Engineering ; Materials ; Nanotechnology ; Optical materials
    ISBN: 9781402089039
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    Unknown
    Berlin, Heidelberg : Springer
    Keywords: Condensed matter ; Engineering ; Nanotechnology ; Surfaces (Physics)
    ISBN: 9783540343158
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    Keywords: Chemistry, inorganic ; Engineering ; Materials
    ISBN: 9783540687580
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Keywords: Biomass conversion ; Biotechnology ; Chemical Engineering ; Chemistry industry ; Industrial Chemistry ; Kent ; Riegel ; biochemical engineering
    Description / Table of Contents: Substantially revising and updating the classic reference in the field, this handbook offers a valuable overview and myriad details on current chemical processes, products, and practices. No other source offers as much data on the chemistry, engineering, economics, and infrastructure of the industry. The Handbook serves a spectrum of individuals, from those who are directly involved in the chemical industry to others in related industries and activities. It provides not only the underlying science and technology for important industry sectors, but also broad coverage of critical supporting topics. Industrial processes and products can be much enhanced through observing the tenets and applying the methodologies found in chapters on Green Engineering and Chemistry (specifically, biomass conversion), Practical Catalysis, and Environmental Measurements; as well as expanded treatment of Safety, chemistry plant security, and Emergency Preparedness. Understanding these factors allows them to be part of the total process and helps achieve optimum results in, for example, process development, review, and modification. Important topics in the energy field, namely nuclear, coal, natural gas, and petroleum, are covered in individual chapters. Other new chapters include energy conversion, energy storage, emerging nanoscience and technology. Updated sections include more material on biomass conversion, as well as three chapters covering biotechnology topics, namely, Industrial Biotechnology, Industrial Enzymes, and Industrial Production of Therapeutic Proteins.
    Pages: Online-Ressource (XIV, 1562 pages)
    ISBN: 9780387278438
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Keywords: Electronics ; Engineering ; Nanotechnology ; Optical materials ; System safety
    ISBN: 9783540269458
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    Keywords: Electronics ; Engineering ; Optical materials ; Spectrum analysis
    ISBN: 9783540274124
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Unknown
    Berlin, Heidelberg : Springer
    Keywords: Electronics ; Engineering ; Optical materials ; Physical optics
    ISBN: 9783540718925
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Keywords: Electronics ; Engineering ; Nanotechnology ; Thermodynamics
    ISBN: 9783540736073
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    Unknown
    Berlin, Heidelberg : Springer
    Keywords: Computer engineering ; Engineering ; Nanotechnology ; Optical materials ; Physical optics ; Quantum optics
    ISBN: 9783540469360
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Unknown
    Berlin, Heidelberg : Springer
    Keywords: Condensed matter ; Engineering ; Magnetism ; Materials ; Nanotechnology
    ISBN: 9783540495765
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Keywords: Computer science ; Engineering ; Materials ; Nuclear engineering ; Thermodynamics
    ISBN: 9781402084225
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Unknown
    Totowa, NJ : Humana Press
    Keywords: Biochemical engineering ; Biotechnology ; Chemical engineering ; Engineering ; Environmental sciences ; Microbiology
    ISBN: 9781592599967
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Unknown
    Berlin, Heidelberg : Springer
    Keywords: Engineering ; Magnetism ; Nanotechnology ; Optical materials
    ISBN: 9783540493365
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Electronic Resource
    Electronic Resource
    Springer
    Computers and the humanities 30 (1996), S. 381-392 
    ISSN: 1572-8412
    Keywords: comparative demographic history ; census ; data set integration ; ICAPUMS ; IPUMS ; coding schemes ; Canada ; United States
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Media Resources and Communication Sciences, Journalism
    Notes: Abstract The comparative use of census data is a useful way to study social characteristics across national boundaries. However, truly comparative demographic history is not possible without fully integrating separate census data, uniting multiple data files with a common set of comparably coded variables. This paper describes the integration of the 1871 Canadian census public use sample with similar samples of the 1850 and 1880 American censuses to form the Integrated Canadian-American Public Use Microdata Series (ICAPUMS). These data sets lent themselves well to integration because of their strong similarities in sampling design, data collection and data organization. Consistency in the availability and treatment of variables also eased integration of the samples, although the harmonization of occupation variables presented significant challenges. The ICAPUMS features a general household relationship variable which allows us to examine household structure across the two countries and three years. The paper concludes by proposing some general principles of census data set integration. This integrated data set is now available to researchers on the website of the University of Minnesota Historical Census Projects (www.hist.umn.edu/~ipums).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Electronic Resource
    Electronic Resource
    Springer
    European journal of law and economics 4 (1997), S. 147-232 
    ISSN: 1572-9990
    Keywords: Methodology ; history of social science ; economists ; political economy ; history ; historical school ; Germany ; England ; United States ; historicism ; economics ; philosophy ; Wolff
    Source: Springer Online Journal Archives 1860-2000
    Topics: Law , Economics
    Notes: Abstract This paper explores the place of Christian Wolff in the history of social science in English. The "Introduction" places Wolff in the context of the pre-history of modern social science. Samples are given of the great range of subjects on which he wrote. The importance of the German context is stressed. The second part is devoted to a sample of what the literature contains by and about Wolff. It emphasizes philosophy and science. Part three is a survey of works in the history of the social sciences that mention Wolff. He has a substantial place in political science and psychology, a much smaller place in economics and history, virtually none in anthropology, geography, and sociology. In the applied social sciences, he is found in the history of education. Possible reasons are given. Part four is devoted to the relationships of philosophy and philosophers in the pre-history of the social sciences. They were important in several different ways because they both shaped and reflected how many people thought about science and social problems. The “Summary and Conclusion” describes the present status. His contributions are summarized. He was a pivotal figure in the making of the German conception of social science. This is a preliminary study emphasizing the issues and problems that a more detailed examination would require. Several conventional judgments are challenged and possibilities for further research suggested.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Electronic Resource
    Electronic Resource
    Springer
    Journal of the history of biology 32 (1999), S. 163-195 
    ISSN: 1573-0387
    Keywords: cytogenetics ; diagrams ; genetics ; illustrations ; McClintock ; models ; molecular biology ; photographs ; twentieth-century ; United States
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , History
    Notes: Abstract Barbara McClintock won the Nobel Prize in 1983 for her discovery of mobile genetic elements. Her Nobel work began in 1944, and by 1950 McClintock began presenting her work on “controlling elements.” McClintock performed her studies through the use of controlled breeding experiments with known mutant stocks, and read the action of controlling elements (transposons) in visible patterns of pigment and starch distribution. She taught close colleagues to “read” the patterns in her maize kernels, “seeing” pigment and starch genes turning on and off. McClintock illustrated her talks and papers on controlling elements or transposons with photographs of the spotted and streaked maize kernels which were both her evidence and the key to her explanations. Transposon action could be read in the patterns by the initiated, but those without step by step instruction by McClintock or experience in maize often found her presentations confusing. The photographs she displayed became both McClintock's means of communication, and a barrier to successful presentation of her results. The photographs also had a second and more subtle effect. As images of patterns arrived at through growth and development of the kernel, they highlight what McClintock believed to be the developmental consequences of transposition, which in McClintock's view was her central contribution, over the mechanism of transposition, for which she was eventually recognized by others. Scientific activities are extremely visual, both at the sites of investigation and in communication through drawings, photographs, and movies. Those visual messages deserve greater scrutiny by historians of science.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    Electronic Resource
    Electronic Resource
    Springer
    Environmental and resource economics 5 (1995), S. 115-129 
    ISSN: 1573-1502
    Keywords: Emission trading ; United States ; sulfur dioxide ; air pollution ; costs ; cost-effectiveness
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Economics
    Notes: Abstract In 1990, the U.S. Congress passed legislation that amended the Clean Air Act to create a new program to mitigate the effects of acid deposition in the U.S. through emission reductions of sulfur dioxide (SO2) and nitrogen oxides (NOx) at electric utility plants across the country. The SO2 reductions, totalling a 40% reduction nationally from 1980 levels or a 10 million ton reduction annually, are achieved largely through an emission trading system, the largest program of its kind designed to date. This trading system has the potential to save up to half of the compliance costs associated with more traditional source-by-source emission limit programs. This paper briefly discusses background on the acid rain issue in the United States, and the principal features of the program, including: a permanent cap on utility emissions of SO2 beginning in 2010, decision to grant up-front allocation of emission credits to reduce individual approvals of trades, the use of continuous emission monitors and automatic penalties to ensure compliance, and integration of the Acid Rain program requirements with other Clean Air Act programs. The paper also discusses the development of the allowance trading market to date, including the types of compliance options chosen and quantity and type of emissions trading being conducted.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    ISSN: 1573-1596
    Keywords: carbon flux ; land use ; former Soviet Union ; United States ; Mexico ; Brazil ; forests
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geography
    Notes: Abstract This research assessed land-use impacts on C flux at a national level in four countries: former Soviet Union, United States, Mexico and Brazil, including biotic processes in terrestrial ecosystems (closed forests, woodlands, and croplands), harvest of trees for wood and paper products, and direct C emission from fires. The terrestrial ecosystems of the four countries contain approximately 40% of the world's terrestrial biosphere C pool, with the FSU alone having 27% of the global total. Average phytomass C densities decreased from south to north while average soil C densities in all three vegetation types generally increased from south to north. The C flux from land cover conversion was divided into a biotic component and a land-use component. We estimate that the total net biotic flux (Tg/yr) was positive (= uptake) in the FSU (631) and the U.S. (332), but negative in Mexico (−37) and Brazil (−16). In contrast, total flux from land use was negative (= emissions) in all four countries (TgC/yr): FSU −343; U.S. −243; Mexico −35; and Brazil −235. The total net effect of the biotic and land-use factors was a C sink in the FSU and the U.S. and a C source in both Brazil and Mexico.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    ISSN: 1573-5052
    Keywords: Alien species ; Anthropogenic disturbance ; Biological invasions ; Forests ; Ground vegetation ; United States
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A probability-based sampling scheme was used to survey plant species composition in forests of 16 states in seven geopolitical regions of the United States (California, Colorado, Minnesota, and parts of the Pacific Northwest, Southeast, Mid-Atlantic, and Northeast) in 1994. The proportion of alien species relative to the total species number and to canopy cover in the ground stratum (0–0.6 m height) was evaluated in 279 plots. Visually evident anthropogenic disturbances (e.g., artificial regeneration, logging, prescribed burning, and grazing by livestock), if any, were recorded on each plot. In each of the seven regions we quantified (1) the percentage of the number of species and total cover comprised of alien species, (2) the difference in these percentages for disturbed and undisturbed plots, and (3) the origin or native range for the alien species. The percentage of alien species ranged from approximately 4.5% (Colorado) to approximately 13.2% (California). The percentage of alien species cover ranged from approximately 1.5% in Colorado to 25% in California. In five regions, species introduced from temperate Eurasia comprised the largest proportion of alien species and cover. In the Southeast, species introduced from far eastern and subtropical Asia dominated the alien flora. In the Mid-Atlantic, the majority of alien species was Eurasian and the majority of alien species cover consisted of far eastern and subtropical Asian species. The proportion of plots in which at least one alien species was recorded was significantly higher in disturbed than undisturbed plots in the Southeast and marginally significantly higher ($p=0.053$) in the Northeast. These results are consistent with other published studies that indicate that anthropogenic disturbance affects the structure and composition of both the ground stratum and upper canopy of forest habitats. In other regions, however, no significant differences were found.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Electronic Resource
    Electronic Resource
    Springer
    Plant ecology 118 (1995), S. 139-152 
    ISSN: 1573-5052
    Keywords: Classification ; Definition ; United States ; Wetland
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In 1979 the US Fish and Wildlife Service published and adopted a classification of wetlands and deepwater habitats of the United States. The system was designed for use in a national inventory of wetlands. It was intended to be ecologically based, to furnish the mapping units needed for the inventory, and to provide national consistency in terminology and definition. We review the performance of the classification after 13 years of use. The definition of wetland is based on national lists of hydric soils and plants that occur in wetlands. Our experience suggests that wetland classifications must facilitate mapping and inventory because these data gathering functions are essential to management and preservation of the wetland resource, but the definitions and taxa must have ecological basis. The most serious problem faced in construction of the classification was lack of data for many of the diverse wetland types. Review of the performance of the classification suggests that, for the most part, it was successful in accomplishing its objectives, but that problem areas should be corrected and modification could strengthen its utility. The classification, at least in concept, could be applied outside the United States. Experience gained in use of the classification can furnish guidance as to pitfalls to be avoided in the wetland classification process.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Electronic Resource
    Electronic Resource
    Springer
    Empirica 23 (1996), S. 229-253 
    ISSN: 1573-6911
    Keywords: Antimerger policy ; United States ; Europe ; efficiency ; L41 ; G34 ; L21
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Notes: Abstract This paper reviews the history of US antimerger policy. This history is divided into three periods: a period in which there was almost no effective antimerger policy at all from 1890 up to 1959, a period of vigorous antimerger policy from 1950 up through 1973, and a period of lax enforcement from 1974 to the present. The paper accounts for these shifts in antimerger policy and discusses their effects. After reviewing the logic and consequences of US antimerger policy, a critique of its permises is offered, particularly as these premises apply to the recent era of lax enforcement. The paper closes with suggestions for an alternative approach to antimerger policy that is consistent with the empirical evidence on why mergers occur and their effects.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    ISSN: 1573-1596
    Keywords: carbon flux ; land use ; former Soviet Union ; United States ; Mexico ; Brazil ; forests
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geography
    Notes: Abstract This research assessed land-use impacts on C flux at a national level in four countries: former Soviet Union, United States, Mexico and Brazil, including biotic processes in terrestrial ecosystems (closed forests, woodlands, and croplands), harvest of trees for wood and paper products, and direct C emission from fires. The terrestrial ecosystems of the four countries contain approximately 40% of the world's terrestrial biosphere C pool, with the FSU alone having 27% of the global total. Average phytomass C densities decreased from south to north while average soil C densities in all three vegetation types generally increased from south to north. The C flux from land cover conversion was divided into a biotic component and a land-use component. We estimate that the total net biotic flux (Tg/yr) was positive (=uptake) in the FSU (631) and the U.S. (332), but negative in Mexico (-37) and Brazil (-16). In contrast, total flux from land use was negative (=emissions) in all four countries (TgC/yr): FSU -342; U.S. -243; Mexico -35; and Brazil -235. The total net effect of the biotic and land-use factors was a C sink in the FSU and the U.S. and a C source in both Brazil and Mexico.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Electronic Resource
    Electronic Resource
    Springer
    Water, air & soil pollution 93 (1997), S. 27-57 
    ISSN: 1573-2932
    Keywords: Acidification ; trends ; sulfate ; nitrate ; United States ; Europe
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract We applied trend analyses to data from the International Cooperative Programme forAcidification of Rivers and Lakes in an attempt to discover regional patterns of long-term changesin surface water chemistry both in Europe and North America, and to relate these changes totrends in deposition. Decreases in surface water SO 3 - concentrations predominated at European sites in theFederal Republic of Germany, The Netherlands, and in Norway, and at the North American sitesin Ontario, Canada, the Adirondacks and Catskill Mountains of New York, U.S.A. Otherpredominating trends in the European sites were decreasing Ca2+ concentrations at many of thesites in The Netherlands, Norway, and Sweden. Increases in NO 3 - were observed at several sites in southern Norway, and in theAdirondack and Catskill regions of eastern New York. This, combined with an increasedoccurrence of declining base cation concentrations may well be responsible for the lack ofdocumented surface water recovery from acidification. Despite region-wide trends in severalvariables of importance in acidification, no correlations between surface water trends and changesin deposition were found using these data.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Electronic Resource
    Electronic Resource
    Springer
    Water, air & soil pollution 93 (1997), S. 27-57 
    ISSN: 1573-2932
    Keywords: Acidification ; trends ; sulfate ; nitrate ; United States ; Europe
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract We applied trend analyses to data from the International Cooperative Programme for Acidification of Rivers and Lakes in an attempt to discover regional patterns of long-term changes in surface water chemistry both in Europe and North America, and to relate these changes to trends in deposition. Decreases in surface water SO4 2− concentrations predominated at European sites in the Federal Republic of Germany, The Netherlands, and in Norway, and at the North American sites in Ontario, Canada, the Adirondacks and Catskill Mountains of New York, U.S.A. Other predominating trends in the European sites were decreasing Ca2+ concentrations at many of the sites in The Netherlands, Norway, and Sweden. Increases in NO3 − were observed at several sites in southern Norway, and in the Adirondack and Catskill regions of eastern New York. This, combined with an increased occurrence of declining base cation concentrations may well be responsible for the lack of documented surface water recovery from acidification. Despite region-wide trends in several variables of importance in acidification, no correlations between surface water trends and changes in deposition were found using these data.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    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.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 224 (1995), S. 201-201 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    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.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 226 (1995), S. 219-219 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    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).
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 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: 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.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    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.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    ISSN: 0003-3146
    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.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    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.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    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.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    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.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    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.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    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.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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.
    Additional Material: 26 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...