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  • 1
    Electronic Resource
    Electronic Resource
    Thermal degradation of polystyrene (1983)
    Springer
    Colloid & polymer science 261 (1983), S. 709-716 
    Details
    ISSN: 1435-1536
    Keywords: thermal degradation ; HIPS ; SAN ; ABS ; activation energy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Molecular weight change studies have shown that the thermal degradation of random copolymers of styrene — namely HIPS, SAN, and ABS-at low temperatures and in air involves random chain scission. The dominant process in the degradation of HIPS is random chain scission due to weak links, whereas in SAN it is intermolecular chain transfer. In ABS, the degradation is initially random scission due to weak links and then mainly intermolecular chain transfer. The infrared spectra show that during degradation the labile weak links are attacked by oxygen and peroxidic free radicals are produced. Via hydrogen abstraction or autoxidation of olefinic links, these free radicals are responsible for the formation of aliphatic ketonic or peroxyester structures, and for isomerization and cyclization. The activation energies of overall degradation of HIPS, SAN, and ABS are 134, 142, and 92 kJ.mol−1 respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01410944
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  • 2
    Electronic Resource
    Electronic Resource
    Thermal oxidative degradation of poly-lactic acid (1982)
    Springer
    Colloid & polymer science 260 (1982), S. 308-311 
    Details
    ISSN: 1435-1536
    Keywords: Polylactic acid ; thermal degradation of polymers ; TGA ; DTA ; activation energy ; thermal oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Polylactic acid have been prepared by solution polymerization of lactic acid. The TG, DTA and isothermal TG studies indicate, 1st order decomposition process with activation energy 22–25 kcal/mole in air.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01447969
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  • 3
    Electronic Resource
    Electronic Resource
    Vibrational spectra of oligomers of glycine in relation to polyglycine (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 1987-1990 
    Details
    ISSN: 0006-3525
    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/bip.1975.360140914
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  • 4
    Electronic Resource
    Electronic Resource
    An active insoluble aggregate of E. coli β-galactosidase (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 35 (1990), S. 94-98 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260350113
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  • 5
    Electronic Resource
    Electronic Resource
    Immobilization of E. coli β-galactosidase and its derivatives by polyacrylamide gel (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 31 (1988), S. 829-833 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: We have recently prepared some crosslinked derivatives of Escherichia coli β-galactosidase by treating the enzyme with bisimidoesters. In this article, we report the results obtained when the native and these crosslinked derivatives are entrapped in polyacrylamide gel lattice. It was found that use of combination of three protective agents, viz., bovine serum albumin, cysteine, and lactose, during immobilization gave an increased yield of 190% in the case of DMA crosslinked preparation. In the case of native enzyme, the Km, pH optimum, and temperature optimum were found to remain unchanged on immobilization. The DMA crosslinked preparation entrapped in polyacrylamide in the presence of BSA, lactose, and cysteine was found to be a significantly better catalyst and hydrolyzed 47% milk lactose as compared to 31% hydrolysis by entrapped native enzyme in 6 h.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260310810
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  • 6
    Electronic Resource
    Electronic Resource
    The polymeric p-quinone as a matrix for enzyme immobilization (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 927-931 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330719
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  • 7
    Electronic Resource
    Electronic Resource
    Solid state 15N NMR study of 15N enriched melamine-formaldehyde resins (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 33 (1995), S. 1449-1460 
    Details
    ISSN: 0887-6266
    Keywords: NMR ; melamine-formaldehyde ; resins structure ; cross-linked ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Molecular dynamics and structure of uncured and cured melamine-formaldehyde resins isotopically 15N enriched at amine sites were studied by solid-state 15N nuclear magnetic resonance (NMR). Spectra recorded with direct (DP) and cross-polarization (CP) pulse sequences reflect two motionally different regions arising from similar chemical structures. DP spectra of uncured resins at higher temperatures have narrow lines and the detection of slightly different structural units is possible. With increasing crosslinking resonances broaden and overlap and the direct detection of individual signals in cured resins is not possible. On the basis of variable contact time, variable spinning speed, and interrupted decoupling experiments three protonated and one nonprotonated group of signals are identified in the CP spectra for all samples. Short polarization-transfer rates, TNH, for nonprotonated nitrogen in uncured and lightly cured samples reveal more effective hydrogen bonding in viscous and rubber-like resins compared to the highly cured rigid resins. The rigid portions of the resins exhibit longer T1 and short T1ρ relaxation times, while the shorter T1 times and longer T1ρ times are associated with the more mobile portion of samples. ©1995 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1995.090331003
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  • 8
    Electronic Resource
    Electronic Resource
    Solid state 13C NMR study of hexa(methoxy methyl)melamine and melamine-formaldehyde selfcondensates (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 33 (1995), S. 1461-1479 
    Details
    ISSN: 0887-6266
    Keywords: melamine-formaldehyde ; solid-state NMR ; self-condensation ; relaxation ; networks ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The structure and molecular dynamics of self-condensation products of three different melamine resins based on hexa(methoxy methyl)melamine are studied by 13C NMR in the solid state. The application of direct (DP) and cross-polarization (CP) pulse sequences shows that uncured and cured melamine resins are motionally heterogeneous systems, with the mobile and rigid parts consisting of the same basic structural units. Viscous lightly cured samples based on commercial melamine-formaldehyde resins contain low-molecular weight species which act as plasticizers. In these resins, three motionally different methyl groups are observed. Their existence is confirmed either by spectral deconvolution or by fitting the experimental signal intensities to the cross-polarization dynamics with the assumption of two cross-polarization-transfer rates. Fast cross-polarizing rigid methyl groups are accompanied with the spinning sidebands. On the basis of DP and CP relaxation measurements, quantitative results for three major structural units are calculated. Problems concerning the 14N-13C quadrupolar interactions and quantitative analysis are discussed. ©1995 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1995.090331004
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  • 9
    Electronic Resource
    Electronic Resource
    Affinity precipitation of proteins (1996)
    Chicester [u.a.] : Wiley-Blackwell
    Journal of Molecular Recognition 9 (1996), S. 356-359 
    Details
    ISSN: 0952-3499
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Affinity precipitation is being studied as a technique to be introduced at an early stage of downstream processing for the selective isolation of proteins. The technique utilizes a heterobifunctional ligand, which, in addition to having affinity for the target protein(s), possesses another function for controlling precipitation. The latter component is comprised of a polymer which can be made reversibly soluble and insoluble by altering a specific parameter such as pH or temperature. Different polymers of natural and synthetic origin have been used for this purpose. The soluble form of the ligand is used for the affinity binding step and precipitation is induced for obtaining separation of the affinity complex. Some of the polymers used in this laboratory include chitosan, alginate, Eudragit S-100 (copolymer of methacrylic acid and methyl methacrylate) and polyethyleneimine. Chitosan and alginate served as natural ligands for wheat germ agglutinin and pectinase, respectively. The aromatic dye Cibacron Blue 3GA coupled to Eudragit S 100 and polyethyleneimine way used for the affinity precipitation of some model enzymes such as lactate dehydrogenase and alcohol dehydrogenase. As prior removal of cell debris, etc., is essential for affinity precipitation, the possibility of integration of the technique with extraction in aqueous two-phase systems was also demonstrated.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    X-ray diffraction studies on shellac/melamine resin blends (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 19 (1975), S. 3385-3386 
    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
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1975.070191224
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