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  • Chemistry  (37)
  • Biochemistry and Biotechnology  (3)
  • Presbytis entellus  (2)
  • 11
    Electronic Resource
    Electronic Resource
    Studies on β-picolinium-p-chlorophenacylide initiated copolymerization of methyl methacrylate with styrene (1987)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 149 (1987), S. 139-150 
    Details
    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 alternierende Copolymerisation von Methylmethacrylat mit Styrol unter Verwendung von β-Picolinum-P-chlorphenacylid als Radikalinitiator bei 55, 60 und 65°C und einer Reaktionszeit von 3 h wurde kinetisch untersucht. Die Copolymerisationsgeschwindigkeit (Rp) ist proportional der Quadratwurzel der Initiatorkonzentration und weist auf einen bimolekularen Abbruch hin. Der durchschnittliche Polymerisationsgrad nimmt mit zunehmender Initiatorkonzentration ab. Die ermittelten Werte für kp2/kt und für die Aktivierungsenergie betragen 1,43 · 10-3 l mol-1 s-1 bzw. 87 kJ mol-1. Die NMR Spektroskopie wurde zur Bestimmung der Struktur, Zusammensetzung und Stereochemie der Copolymeren verwendet.
    Notes: The alternating copolymerization of methyl methacrylate (MMA) with styrene (S) using β-picolinium-p-chlorophenacylide (β-PCPY) as radical initiator at 55, 60, and 65°C for 3 h has been kinetically investigated. The copolymerization rate (Rp) is proportional to the square root of [β-PCPY] and indicates bimolecular termination. The average degree of polymerization decreases as [β-PCPY] increases. The values of kp2/kt and energy of activation have been evaluated as 1.43 · 10-3 l mol-1 s-1 and 87 kJ mol-1, respectively. The NMR spectroscopy has been used to determine the structure, composition, and stereochemistry of copolymers.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1987.051490111
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  • 12
    Electronic Resource
    Electronic Resource
    Polyvinyl acetate as a template for the radical polymerization of methyl methacrylate (1989)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 170 (1989), S. 127-135 
    Details
    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 Matrizenpolymerisation von Methylmethacrylat (MMA) in Gegenwart von ataktischem Polyvinylacetat (at-PVAC, M̄v = 55 800) bei 60°C in Dimethylformamid (DMF) wurde dilatometrisch gemessen, um die Einflüsse der Konzentration der Matrize, des Monomeren und des Initiators auf die Kinetik zu untersuchen. Die resultierenden Auftragungen der relativen Polymerisationsgeschwindigkeit (VR) gegen die at-PVAC- und MMA-Konzentration zeigen, daß die Polymerisation in diesem System aus einer Kombination von drei verschiedenen Reaktionsmechanismen besteht: die unbeeinflußte Reaktion und zwei Matrizenmechanismen (I und II). Die Reaktionsordnung bezüglich Matrize, Monomerem und Initiator beträgt 0,66, 0,75 und 0,40. Viskosimetrische Messungen zeigten, daß die Komplexierung zwischen at-PVAC und PMMA bei einem Matrize/Polymer-Verhältnis von 1 : 1 am größten war. Die Zeit für eine vollständige Komplexierung betrug 10 min. Die Gesamtaktivierungsenergie betrug 33,5 kJ mol-1 in Gegenwart und 25,0 kJ mol-1 in Abwesenheit von at-PVAC.
    Notes: The template polymerization of methyl methacrylate (MMA) along with atactic polyvinyl acetate (at-PVAC, M̄v = 55880) at 60°C for 120 min in dimethyl formamide (DMF) has been measured dilatometrically to study the effects of the concentrations of template, monomer, and initiator upon the kinetics. The resulting plots of relative polymerization rate (VR) vs. the at-PVAC- and MMA-concentration showed that in the present system the polymerization is a combination of three different reaction mechanisms, the blank reaction and two template mechanisms (I and II). The order of reaction with respect to template, monomer and initiator is 0.66, 0.75 and 0.40, respectively. Viscometric measurements showed that complexation between at-PVAC and PMMA was maximum when the template/polymer ratio was 1 : 1 and the time required for complete complexation was 10 min. The overall energy of activation was 33.5 and 25.0 kJ mol-1 in the presence and absence of at-PVAC, respectively.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1989.051700109
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  • 13
    Electronic Resource
    Electronic Resource
    Polymerization of methacrylic acid and acrylonitrile by p-nitrobenzyl triphenyl phosphonium ylide (1991)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 31 (1991), S. 567-570 
    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: Radical polymerization of methacrylic acid (MAA) and acrylonitrile (AN) in the presence of p-nitrobenzyl triphenyl phosphonium ylide (p-NBTPy) in dimethyl sulphoxide at 65 ± 0.1°C under inert atmosphere was investigated by dilatometry. The ylide failed to initiate the polymerization, but significantly accelerated the rate of polymerization. An interesting feature is that the average polymer molecular weight (M̄v) is a direct function of [p-NBTPy]. The radical polymerization of MAA follows ideal kinetics since calculated monomer and initiator (AIBN) exponents are unity and 0.5, respectively. However, the AN system follows non-ideal kinetics due primarily to radical termination and transfer reactions. The energy of activation, in the presence of p-NBTPy, is low. The accelerating effect of p-NBTPy has been attributed to decreased termination because the ylide did not affect the rate of decomposition of AIBN, as well as form a complex with monomer(s).
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760310806
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  • 14
    Electronic Resource
    Electronic Resource
    Copolymerization of zinc acrylate with acrylonitrile initiated by As2S3-styrene complex (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 34 (1994), S. 105-109 
    Details
    ISSN: 0959-8103
    Keywords: Zinc acrylate ; acrylonitrile ; As2S3-styrene complex ; copolymerization ; dilatometry ; kinetics ; 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: Radical copolymerization of zinc acrylate (ZnA2) with acrylonitrile (AN), initiated by As2S3-styrene complex(I), in dimethyl Sulphoxide (DMSO) at 90 ± 0.1°C for 1.0h under inert atmosphere, yields non-alternating copolymers. The kinetic expression is Rp ∝ [I]0.33 [ZnA2]0.25 [AN]0.44, i.e. the system follows non-ideal kinetics, which is due to primary radical termination as well as degradative chain transfer reactions. The values for activation energy (E) and k2p/kt are 128kJ mol-1 and 8.57 × 10-7 litre mol-1 s-1, respectively. Thermal stability, solubility in different solvents, and IR and NMR spectra have been evaluated.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210340114
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  • 15
    Electronic Resource
    Electronic Resource
    Interpenetrating polymer networks: A review on synthesis and properties (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 35 (1994), S. 109-118 
    Details
    ISSN: 0959-8103
    Keywords: Interpenetrating polymer networks ; synthesis ; properties ; mechanism ; structure-property relationship ; 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: A review containing 83 references on the chemistry aspects (mechanism and structure-property relationships) for IPN synthesis is presented.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210350201
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  • 16
    Electronic Resource
    Electronic Resource
    p-acetyl benzylidene triphenylarsonium ylide initiated radical terpolymerization of styrene, acrylonitrile and copper acrylate: synthesis, characterization and properties (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 41 (1996), S. 407-412 
    Details
    ISSN: 0959-8103
    Keywords: terpolymerization ; kinetics ; thermal properties ; arsonium ylide ; styrene ; acrylonitrile ; copper acrylate ; 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: Solution terpolymerization of styrene (Sty), acrylonitrile (AN) and copper acrylate (CuA) has been carried out in dimethylformamide at 90°C for 4 h using p-acetyl benzylidene triphenylarsonium ylide as radical initiator. 1H nuclear magnetic resonance (NMR), IR and elemental analysis have been used to characterized the terpolymer. Analysis of kinetic data indicates the following rate equation: $$R_{\rm p} \propto \left[ {{\rm ylide}} \right]^{0.5} \left[ {{\rm Sty}} \right]\left[ {{\rm AN}} \right]{1 \over {\left[ {{\rm CuA}} \right]}}$$ The overall activation energy is 38 kJ mol-1. The composition of terpolymer calculated from NMR and elemental analysis has been used to evaluate reactivity ratios as r1(Sty) = 5 ± 2 and r2(AN + CuA) = 0.4 ± 0.02 employing the Finemann-Ross method, which confirms its random origin. The terpolymer was thermally stable up to 2007deg;C.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    Spontaneous current emission in metal-ferrocene-doped ethyl cellulose-metal systems (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 35 (1994), S. 153-159 
    Details
    ISSN: 0959-8103
    Keywords: spontaneous current emission ; activation centres ; barrier polarization ; plasticization effect ; 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: Spontaneous current emission (SCE) has been studied in sandwiched different electrode configurations [metal(1)-undoped/doped ethyl cellulose (EC)-metal (1)/(2)] as a function of heating rate, film thickness and dopant concentration in the temperature range 40-200°C. The magnitude and direction of current depend on the combination of electrode metals. SCE thermograms for the Al undoped/doped EC-AI system exhibit two well resolved transition at 110 and 160°C in opposite directions to each other. The phenomena related to these transitions are explained in terms of creation of field at the interfaces and field produced in the bulk of the material. No negative direction transition was observed for electrode systems like Ag-Ag, Pb-Pb, Sn-Sn and Au-Au except for a shoulder of a peak around 100°C. When dissimilar electrode systems (i.e. Al-undoped/doped EC-Ag/Pb/Sn) are used, the current rises and then saturates beyond around 160°C.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210350205
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  • 18
    Electronic Resource
    Electronic Resource
    Synthesis of zinc-containing epoxy resin (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 51 (1994), S. 203-211 
    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: Novel epoxy resins containing zinc acrylate have been synthesized by reacting zinc acrylate with bisphenol-A and an excess of epichlorohydrin. Parameters such as epoxy equivalent weight, hydroxyl content, and hydrolyzable chlorine content have been estimated. These resins, characterized by IR, 1H-NMR, and 13C-NMR, have been evaluated by thermal analysis. Curing was carried out with polyamide at 130°C for 24 h. Cured resins have improved thermal and chemical resistance. The reaction follows first-order kinetics with activation energy 86 and 34 kJ mol-1 in the presence and absence of zinc acrylate. The role of zinc, which increases epoxidation due to formation of complex with bisphenol-A, has been discussed. © 1994 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1994.070510201
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  • 19
    Electronic Resource
    Electronic Resource
    Effect of sulfur mustard on microhardness of poly(ethylene terephthalate) films (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 60 (1996), S. 147-151 
    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: The effect of sulfur mustard (SM), a well-known chemical warfare agent on the microhardness of two poly(ethylene terephthalate) (PET) films was investigated at different loads. SM induces hardness in PET films, perhaps due to an antiplasticizing effect. Heat treatment of the films enhanced their microhardness. The heat-set films show a further increase in their microhardness after exposure to SM. These results were supported by physicochemical techniques like plasma and amine etching, which revealed complex etching phenomena giving rise to a structure-specific pattern. The film having a higher weight loss due to plasma and amine etching showed lower microhardness. © 1996 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 20
    Electronic Resource
    Electronic Resource
    Birefringence in an epoxy polymer during stress-relaxation and recovery (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 29 (1984), S. 1241-1248 
    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: Measurements of birefringence during stress-relaxation and recovery have been recorded for examples of an epoxy resin cured at three different temperatures. Birefringence remained constant during stress-relaxation even after prolonged testing during which the stress fell considerably. The stress sensitivity was found to be the same on both loading and unloading so that, immediately after unloading, the birefringence was different to that prior to the stress-relaxation test. This residual change began to decay after a prolonged period free from applied stress. No significant differences were noted in the birefringence measurements made on samples cured at different temperatures, but, when the stress-relaxation data were analyzed by the procedure of Kubát and Rigdahl, marked differences appeared.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1984.070290419
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