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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 239 (1996), S. 133-149 
    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 Zähigkeit von Polyarylaten wurde durch den Einbau von 4,4′-Thiodiphenol und Bisphenol A, die in der wäßrigen Phase einer Grenzflächenpolykondensation vorgelegt wurden, erhöht. Die modifizierten Polyarylate besitzen leicht erniedrigte Zugfestigkeiten und Zugmoduli, aber aufgrund der Flexibilität der eingebauten Segmente stark erhöhte Izod-Schlagzähigkeiten. Darüber hinaus bleiben die guten thermischen Eigenschaften der Polyarylate nach der Modifizierung erhalten, so daß die hergestellten Materialien auch für Anwendungen mit sehr hohen Anforderungen an die thermische Belastbarkeit geeignet sind.
    Notes: The toughness of polyarylates was improved by incorporation of 4,4′-thiodiphenol and bisphenol A, being introduced in the aqueous phase of an interfacial polycondensation reaction. The modified polyarylates possessed slightly lower tensile strength and modulus but much higher Izod impact strength due to the flexibility of the incorporated segments. In addition, the superb thermal properties typical for polyarylates were reserved in the modified polyarylate, thus assuring its broad applicability for those applications where extremely stringent criteria of thermal characteristics are required.
    Additional Material: 16 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 248 (1997), S. 123-137 
    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 Kinetik der Polyarylastynthese durch Grenzflächenpolykondensation von Bisphenol A mit Tere-/Isophthalsäuredichlorid wurde durch UV-spektrometrische Verfolgung der Bisphenolatkonzentration in der wäßrigen Phase untersucht. Der Reaktionsmechanismus besteht aus drei Schritten, von denen der dritte Schritt geschwindigkeitsbestimmend ist: 1. Transport von Bisphenolat in der wäßrigen Phase; 2. Transfer von Bisphenolat durch die Grenzschicht und Transport in der organischen Phase; 3. Reaktion von Bisphenolat mit Säuredichlorid in der organischen Phase. Der Einfluß der Konzentration der Reaktanden in der wäßrigen bzw. organischen Phase und der Menge des Phasentransferkatalysators auf den Verlauf der Grenzflächenpolykondensation wurde untersucht.
    Notes: For the synthesis of polyarylate by interfacial polycondensation of bisphenol A with terephthaloyl/isophthaloyl dichloride, the kinetic mechanism was studied through the detection of the concentration of bisphenolate in the aqueous phase by UV spectrometry. The mechanism consists of three steps: 1. the transportation of bisphenolate in the aqueous phase, 2. the transfer of bisphenolate through the interface followed by its transportation in the organic phase, 3. the reaction of bisphenolate with the phthaloylic dichloride in the organic phase. The reaction of bisphenolate with the phthaloylic dichloride in the organic phase is the rate-determining step. The influence of the concentration in either the aqueous phase or the organic phase and of the quantity of the phase transfer agent on interfacial polycondensation were studied.
    Additional Material: 9 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 3073-3080 
    ISSN: 0887-624X
    Keywords: direct esterification ; BHET ; EG ; DEG ; OH reactivity ; kinetics ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: For revealing diethylene glycol (DEG) formation in poly(ethylene terephthalate) (PET) synthesis, this research focused on finding the stage most critical for DEG formation. It is found that the esterification stage was the most critical stage for DEG formation during production of PET through the direct esterification process. In addition, the kinetics of the formation of DEG (ether bond), which is mainly produced from hydroxyl end groups of ethylene glycol (EG) and bis-hydroxyethyl terephthalate (BHET) oligomer, was investigated. The results show that the reactivity of BHET-OH functional group is greater than that of EG-OH functional group in the reaction to produce ether bonds. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 3073-3080, 1998
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  • 4
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 3081-3087 
    ISSN: 0887-624X
    Keywords: TPA ; mol ratio ; DEG ; kinetics ; protons ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This research focused on studies of the effect of terephthalic acid (TPA) addition at the initial feed on diethylene glycol formation (DEG) in the process of polyethylene terephthalate (PET) preparation. Experimental results show that, when the mol ratio of ethylene glycol (EG) with TPA ranges from 1.0 to 1.3, the greater the amount of TPA added at the initial feed, the more DEG formed, and the greater the suppression of the rate of esterification and polymerization. In addition, the kinetics of EG with protons in the etherification reaction was considered in the study. It is found that, during the etherification reaction, the reactivity of hydroxyl end groups with ether bonds is higher than that of hydroxyl end groups on their own, and the activation energy of EG with protons is much lower than that of pure EG on its own. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 3081-3087, 1998
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 237 (1996), S. 173-189 
    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: Zwei aromatische Polyamide auf Naphthalin-Basis wurden durch modifizierte Higashi-Phosphorylierung aus Naphthalin-2,6-dicarbonsäure und aromatischen Diaminen hergestellt. Das erste Polymere, Poly(4,4′-diaminobenzanilid-2,6-naphthyl-amid)* (DBNA), wurde aus Naphthalin-2,6-dicarbonsaure und 4,4'-Diaminobenzanilid erhalten. Zur Synthese des zweiten Polymeren, 50/50-Copoly(1,4-phenylen/1,4-bis(4'-phenoxy) phenylen-2,6-naphthylamid)** (PBNA), wurden aquimolare Mengen 4-Phenylendiamin und 1,4-Bis(4'-aminophenoxy)benzol rnit Naphthalin 2,6-dicarbonsaure umgesetzt. Die Polymeren mit inhajenten Viskositaten von 4,17 bzw. 2,32 dL g-' sind in LiC1-haltigem N-Methylpyrrolidon (NMP) loslich. Durch FilmgieBen wurden hochfeste Filme erhalten. Blends aus DBNA bzw. PBNA mit amorphem Nylon wurden durch rasches Fallen der temaren NMP-Losungen in deionisiertem Wasser hergestellt und bei 185 C zu Filmen geprel3t. Die Vertraglichkeiten, Morphologien und mechanischen Eigenschaften der Polyamide wurden durch dynamisch-mechanische Analyse, Rasterelektronenmikroskopie und Zugversuche charakterisiert. Die Ergebnisse zeigten, dalj beide Polyamide rnit Nylon teilweise kompatibel sind. DBNA bildet Mikrofibrillen in der Nylonmatrix, und Zugfestigkeit sowie Zugmodul des Blends nehmen rnit steigendem DBNA-Gehalt zu. PBNA bildet keine Mikrofibrillen in der Nylonmatrix und zeigte, moglicherweise aus diesem Grund, keinen die Matrix verstarkenden Effekt.
    Notes: Two naphthalene-aromatic polyamides were prepared from 2,6-naphthalenedicarboxylic acid and various aromatic diamines by a modified Higashi phosphorylation reaction. The first polymer, poly(4,4′-diaminobenzanilide-2,6-naphthalamide)** (DBNA), was synthesized by the reaction of 2,6-naphthalenedicarboxylic acid with 4,4′-diaminobenzanilide. The second polymer, 50/50 copoly(1,4-phenylene/1,4-bis(4′-phenoxy)benzene-2,6-naphthalamide)*** (PBNA), is a copolymer synthesized using an equimolar ratio of 1,4-phenylene diamine and 1,4-bis(4′-aminophenoxy)benzene. These two polymers have inherent viscosities of 4.17 and 2.32 dL g-1, respectively, and dissolve in N-methyl-2-pyrrolidone (NMP)containing LiCl. Highstrength films were obtained by casting from these polymer solutions. Blends of DBNA/amorphous nylon and of PBNA/amorphous nylon were prepared by rapidly precipitating the ternary NMP solution into deionized water, and hot-pressing to films at 185°C. The compatibility, morphology, and mechanical properties were investigated by dynamic mechanical analysis (DMA), scanning electron microscopy (SEM), and tensile tests. The results revealed that both DBNA and PBNA were partially compatible with amorphous nylon. DBNA formed microfibrils in the amorphous nylon matrix, and its mechanical properties, tensile strength and modulus, improved with increasing DBNA content. PBNA had no reinforcing effect, perhaps because it did not form microfibrils in the amorphous nylon matrix.
    Additional Material: 10 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 44 (1992), S. 1087-1093 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Composite membranes were prepared by interfacial polycondensation of a water-soluble diamine (4,4′;-methylene dianiline [MDA] or ethylene diamine [EDA]) with an organic solvent (hexane)-soluble 1,2,4,5-benzenetetra acyl chloride (BTAC) on top of a porous polysulfone (PSF) support. For both the poly(BTAC-MDA) and poly(BTAC-EDA) composite film systems, the permselectivity of these films increases only slightly with an increasing number of coatings. The poly(BTAC-MDA) composite membranes are treated at 135°C in a nitrogen atmosphere for 4 h, and they have a high selectivity [α*(CO2/CH4) = 20.51] and permeability [P̄(CO2) = 44.12 Barrer]. This is due mainly to the great chain stiffness of the formed polyimide, which has high selectivity. The high permeability is due to a porous polysulfone support. The trend of the permeability for this composite film is P̄(CO2) 〉 P̄(O2) 〉 P̄(N2) 〉 P̄(CH4). In poly(BTAC-EDA) composite membranes, the permeation of different gases decreases in the order of P̄(CO2) 〉 P̄(O2) 〉 P̄(CH4) 〉 P̄(N2). As to the composite films being more permeable to CH4 than to N2, this is probably due to the presence of a considerable quantity of aliphatic chains (-CH2-CH2-) in the poly(BTAC-EDA) composite film caused by its particularly excellent solubility for methane.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 43 (1991), S. 39-48 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: This research tried to simulate three stages of injection molding cycles (filling, packing, and cooling) for polypropylene. The cavity used was a center-grated disk-shaped mold. During the filling stage, we assumed the polymer fluid obeyed the CEF equation and flowed nonisothermally. The packing stage was represented by isothermal flow of Newtonian fluid, and, during cooling stage, we took into account the effect of pressure drop on the energy balance. By finite difference method, we could solve the partial differential equations numerically. The results showed. (1) Elastic effect was not significant at the filling stage. (2) Pressure buildup in the cavity was very quick at the packing stage. (3) At the cooling stage, temperatures predicted by taking into account pressure drop were lower than those without considering pressure drop. In addition, the influences of mold temperature, flow rate, and inlet melt temperature on the three stages of injection molding process were discussed.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 42 (1991), S. 2543-2550 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: 1,2,4,5-Benzenetetra acyl chloride (BTAC) was prepared from pyromellitic anhydride and phosphoric chloride. The behavior in interfacial polycondensation of 4,4′-methylene dianiline (MDA) or ethylene diamine (EDA) in water with BTAC in dichloromethane with tetrabutyl ammonium chloride (TBAC) as the catalyst was examined with Fourier transform infrared spectroscopy (FTIR), fast atom bombardment mass spectroscopy (FABMS), and scanning electron microscope (SEM). A heat-resistant film can be obtained by successive heating of the resulting thin films.Because BTAC is a tetrafunctional compound with high reactivity, the interfacial reaction is a competitive reaction of hydrolysis and amidation among the reacting groups. The optical density of FTIR spectra was employed for calculating the percentage of hydrolysis. The hydrolysis is suppressed when (1) the temperature is decreased, (2) sodium carbonate is added, (3) the proportion on the concentration of diamine is increased relative to the concentration of BTAC, (4) the diamine solution is agitated, and (5) TBAC is added to the diamine (as).The percentage of hydrolysis can be controlled at will, e.g., 50%. A high-resistant polyimide can be prepared through thermal treatment in a nitrogen atmosphere. By increasing the concentration of the reactants or using a good sovlent, the film obtained is thicker, but in our system, the maximum thickness of the film seldom exceeded 20 pm.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 40 (1996), S. 93-98 
    ISSN: 0959-8103
    Keywords: phosphorus pentoxide/methanesulphonic acid ; polynaphthimidazoles ; 2,6-naphthalene dicarboxylic acid ; dimethyl 2,6-naphthalene dicarboxylate ; thermal stability ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Phosphorus pentoxide/methanesulphonic acid (PPMA) was used as both solvent and condensing agent for the preparation of polynaphthimidazoles (PNIs) through direct polycondensation. The reactions of 2,6-naphthalene dicarboxylic acid and dimethyl 2,6-naphthalene dicarboxylate with tetramine monomer were studied with varying concentration of monomer, reaction temperature and reaction time in order to obtain high-molecular-weight polymer with high conversion. The properties, including solvent resistance, thermal properties and film casting, of synthesized polymers were also investigated. It was found that, using PPMA as both solvent and condensing agent, PNIs can be prepared successfully with high molecular weight by direct polycondensation of 2,6-naphthalene dicarboxylic acid or its derivatives with tetramine. The PNIs had inherent viscosities in the range 0.94-2.38 dl/g (in conc. H2SO4 at 30°C); however, polymers synthesized from isophthalic and terephthalic acids with tetramine had inherent viscosities of only 0.56dl/g and 0.48dl/g, respectively, with low conversions under similar reaction conditions. The glass transition temperature of the PNI 1 was 403°C. Thermal analysis indicates that these PNIs have excellent thermal stability, and the 10 wt% loss temperatures were recorded in the range 588-648°C in nitrogen gas, 533-580°C in air. The chemical stability and mechanical properties of films are also outstanding.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 42 (1991), S. 3111-3122 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The crystallization kinetics and morphology of glass fiber-reinforced polypropylene (PP/GF) were investigated in this work. Both isothermal and nonisothermal crystallization behaviors of 90PP/10GF, 80PP/20GF, and 70PP/30GF were examined with a DSC instrument. It was found that the addition of glass fiber would increase the crystallization rate of PP and increase the content of β spherulite, which was most likely formed at temperatures between 390 and 400 K. The morphology of spherulites of PP/GF composites were examined with SEM and a polarized microscope. All experimental observations conformed rather well with the theoretical approach, a dynamic crystallization model, proposed in our previous work. The size of α spherulites of PP would decrease at lower crystallization temperature, or at higher cooling rate, or by adding glass fiber in it.
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