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  • 1
    Electronic Resource
    Electronic Resource
    Flow properties of concentrated solutions of polyarylate in m-cresol (1987)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 1129-1136 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The flow properties of concentrated solutions of polyarylate from bisphenol A/50:50 isophthalic acid: terephthalic acid in m-cresol are studied. The results are discussed in terms of critical concentration Cc and critical molecular weight Mc for the onset of entanglements. Values of Cc = 8,2 wt.-% and Mc ≈ 3500 are obtained. The dependence of the Newtonian viscosities with temperature allows to obtain different energies of activation of flow for each polyarylate/m-cresol system, ranging from 9 to 13 kcal/mol (= 37,7 to 54,4 kJ/mol). The following free-volume-additivity equation is proposed to fit these data: \documentclass{article}\pagestyle{empty}\begin{document}$ E_{\rm a} = \frac{{V_{\rm p} \cdot \alpha _{\rm p} \cdot E_{{\rm ap}} + V_{\rm d} \cdot \alpha _{\rm d} \cdot E_{{\rm ad}} }}{{V_{\rm p} \cdot \alpha _{\rm p} + V_{\rm d} \cdot \alpha _{\rm d} }} $\end{document} where Ea, Eap, and Ead are the activation energies of the solution, the polymer and the solvent, respectively. Vp and Vd are the polymer volume fraction and the diluent volume fraction, respectively, and αp and αd represent the differences between the volume coefficients of expansion above and below the corresponding glass transition temperatures for the polymer and the solvent.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1987.021880515
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  • 2
    Electronic Resource
    Electronic Resource
    Preparation and crystalline structure of random copolymers of glycine and β-alanine (1989)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 190 (1989), S. 1379-1387 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Copolymers of glycine and β-alanine within a range of amount-of-substance compositions from 3:1 to 1:9 were prepared by polycondensation of mixtures of the respective pentachlorophenyl ester hydrobromides. Number-average molecular weights between 2 500 and 9 000 were obtained, the lower values corresponding to those copolymers with a higher content in glycine. Sequence distributions were evaluated by means of 50,3 MHz 13C NMR spectroscopy and the crystalline structure was examined by wide-angle X-ray diffraction. Random copolymers having similar contents in glycine and β-alanine were found to crystallize in a bidimensional hexagonal lattice (a = 4,79 Å) with chains packed in a similar manner as they do in the crystalline structure of polyglycine II. On the contrary, a heterogeneous product consisting of homopolymer and random copolymer fractions results from mixtures which are enriched in one of the two amino acids. The random copolymer poly(glycine-ran-β-alanine) adopts a packing scheme similar to that found for the helical form of the alternating copolymer nylon 2/3. Chains are hexagonally arranged and interlinked by a three-dimensional network of hydrogen bonds as described for the well known model of polyglycine II, although in the present case no order along the chain axis should be expected.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1989.021900618
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesis and structural data of nylon 1,4 (1987)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 25 (1987), S. 1445-1448 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1987.080250520
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  • 4
    Electronic Resource
    Electronic Resource
    Degradation and stabilization of high molecular weight polyethylene in solution (1987)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 25 (1987), S. 2469-2477 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The changes in the molar mass of high molecular weight polyethylene, in o-dichlorobenzene, with time are examined using viscometry. The results show that the molar mass decreases with time and that the observed decay can be satisfactorily explained by a simple degradation model. Commercial antioxidants can inhibit the degradation process if the appropriate concentration is chosen. Thus, at very low concentrations a polynuclear phenol shows good antioxidant behavior but this decreases with an increase in concentration due to direct oxidation of the inhibitor. Conversely, zinc dimethyldithiocarbamate shows the best stabilizing activity which increases with concentration. The results are explained on the basis of the established mechanistic action of these compounds and show that viscometry is not an accurate method for measuring the molar mass of high molecular weight polyethylene samples unless the appropriate conditions are chosen. Even with the best inhibitor, some degradation is still observed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1987.080250912
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  • 5
    Electronic Resource
    Electronic Resource
    Effect of different gas environments on bench-scale solid state fermentation of oat straw by white-rot fungi (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 382-387 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Three white-rot fungi, Phanerochaete chrysosporium, Polyporus tulipiferae, and Polyporus sp. A336 were grown on 100-g amounts of chopped oat straw in gassed 4.5 L (diameter 16 cm, height 23 cm) solid-state reactors for two weeks. The different gas atmospheres were regulated by (1) air diffusion through foam plugs, (2) intermittent or continuous air flow, (3) intermittent oxygen, 50 or 100% continuous oxygen flow, and (4) continuous 10% carbon dioxide in oxygen flow. The fermented straw was analyzed for total weight loss, Klason lignin loss, and enzymatic (cellulase) hydrolysis. P. chrysosporium grown on straw in continuous oxygen at 35°C caused a 41% weight loss and 33.5% hydrolysis was obtained when the pretreated straw was hydrolyzed with cellulase enzyme. P. tulipiferae caused a 27% weight loss and 34.3% cellulase hydrolysis in the straw at 30°C. Polyporus sp. A336 selectively degraded lignin of the straw and under intermittent oxygen resulted in an 18% weight loss and 33.6% cellulase hydrolysis at 35°C. When the straw was supplemented with 10% xylose (straw basis) and was continuously gassed with 50% oxygen, Polyporus sp. A336 produced a 14.5% weight loss and 38.7% cellulase hydrolysis. Oxygen and carbon dioxide exchange rates were measured for some of these bench-scale fermentations.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270324
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  • 6
    Electronic Resource
    Electronic Resource
    The observation of a sub(gel-sol) transition in PVC/DOP gels (1988)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 26 (1988), S. 1871-1880 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Dynamic viscoelastic measurements on poly(vinyl chloride)/dioctyl phthalate gels have been carried out in parallel-plate shear mode. Two transitions are observed: the well-known gel-sol transition at temperature Tf, which probably corresponds to the beginning of fusion of crystalities, and a transition, at a temperature below Tf, denoted as Ts and corresponding to phase separation. The sub(gel-sol) Ts temperature is manifested as the transition from the first plateau zone to a second plateau in log G' versus temperature plots. Other techniques like polarizing microscopy and DSC measurements are not adequate for the detection of Ts.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1988.090260905
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  • 7
    Electronic Resource
    Electronic Resource
    Crystal structure of nylons 2/3/3 and 1,3 (1987)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 25 (1987), S. 513-523 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The crystal structures of two polyamides, poly(glycyl-β-alanyl-β-alanine) (nylon 2/3/3) and poly(methylene malonamide) (nylon 1,3), have been investigated by x-ray diffraction and electron microscopy. Crystallization of nylon 2/3/3 from a solution in a mixture of water and formic acid yields lamellar single crystals exhibiting a triangular habit. Doughnut-shaped morphologies diffracting as single crystals are obtained in the crystallization of nylon 1,3. A helical structure of the type known as polyglycine II is found for both polyamides. In such a structure, chains are intermolecularly linked by hydrogen bonds giving a hexagonal lattice of a = 4.79 Å. Insufficient data are available to determine precisely the conformation of the chains. We assume a threefold helix having c = 35.2 Å and c = 18.0 Å for nylon 2/3/3 and nylon 1,3 respectively. No sign of the layered structure familiar in polyamides has been detected for these polymers throughout the experiments made in the present study.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1987.090250305
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  • 8
    Electronic Resource
    Electronic Resource
    Preliminary study of the crystal structure of nylon 2/11 (1989)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 27 (1989), S. 1563-1567 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1989.090270717
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  • 9
    Electronic Resource
    Electronic Resource
    Rheological and processing characteristics of polystyrene in the vicinity of Tll transition (1985)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 25 (1985), S. 188-191 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: Rheological and processing parameters have been measured for a commercial polystyrene at temperatures from 155°C to 210°C resulting in no clear evidence for the existence of liquidliquid transition. Zero shear viscosities obtained from dynamic measurements and ends corrections and extrudate swell from capillary rheometry are analyzed, with the conclusion that the mechanism of flow is the same throughout the range of temperatures considered.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760250308
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  • 10
    Electronic Resource
    Electronic Resource
    A comparison of some rheological properties of concentrated solutions of chlorinated polyethylene and polyvinyl chloride in dioctyl phthalate (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 31 (1986), S. 911-917 
    Details
    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: Steady-state and transient shear flow properties of poly(vinyl chloride) and chlorinated polyethylene dissolved in dioctyl phthalate were studied at different temperatures and polymer concentrations. In the case of poly(vinyl chloride)/dioctyl phthalate systems the presence of a sol-gel transition temperature was observed, whereas for chlorinated polyethylene/dioctyl phthalate systems the mechanism of flow was the same in the whole range of temperatures and concentrations. On the basis of the data obtained for both polymer/solution systems, we conclude that the presence of crystallites, rather than hydrogen bonds, determines the rheological behavior of poly(vinyl chloride)/dioctyl phthalate systems.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1986.070310314
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