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  • 1985-1989  (20)
  • Chemistry  (19)
  • Presbytis entellus  (1)
  • Agglutination
  • 1
    Electronic Resource
    Electronic Resource
    Studies on polymerization of vinyl acetate using ylide as an initiator and degradative transfer agent (1989)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 27 (1989), S. 807-815 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polymerization of vinyl acetate initiated by β-picolinium p-chlorophenacylide was carried out at 30, 35, and 40°C, using conventional dilatometric technique. The initiator and the monomer exponent values were 0.80 ± 0.15 and unity, respectively. The polymerization was inhibited in the presence of hydroquinone, but was favored by nonpolar solvent and polymerization temperature. The energy of activation was 90.3 KJ mol-1. An average value of kp2/kt for the present system was found to be 0.37 × 10-2. The results are explained in terms of a radical mode of polymerization with degradative initiator transfer; the principal mode of termination, however, was bimolecular.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1989.080270306
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  • 2
    Electronic Resource
    Electronic Resource
    Studies on polymerization of vinyl acetate using ylide as an initiator and degradative transfer agent (1989)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 27 (1989), S. 43-51 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of vinyl acetate initiated by β-picolinium-p-chlorophenacylide was carried out at 30, 35, and 40°C, using the conventional dilatometric technique. The initiator and the monomer exponent values were 0.80 ± 0.15 and unity, respectively. The polymerization was inhibited in the presence of hydroquinone, but was favored by nonpolar solvent and polymerization temperature. The energy of activation was 90.3 kJ mol-1. An average value of kp2/kt for the present system was found to be 0.37 × 10-2 L mol-1 s-1. The results are explained in terms of radical mode of polymerization with degradative initiator transfer; the principal mode of termination, however, was biomolecular.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1989.080270104
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  • 3
    Electronic Resource
    Electronic Resource
    Poly(vinyl acetate) as a template for the radical polymerization of acrylonitrile (1989)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 27 (1989), S. 1065-1070 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The template polymerization of acrylonitrile (AN) along with atactic-poly(vinyl acetate) of Mv (47,090), at 60°C for 120 min in dimethyl formamide (DMF) has been studied dilatometrically to study the effects of template, monomer, and initiator (benzoyl peroxide) concentration upon kinetics. Viscometric measurements showed that complexation between at-PVAc and PAN was maximum when template/polymer ratio was 1:1 and time required for complete complexation was 15 min. The overall energy of activation was 57.76 and 77.01 kJ/mol in the presence and absence of, PVAc, respectively. The overall system follows mechanism I, i.e., the monomer molecules get adsorbed on the surface of the template macromolecules and then propagation proceeds.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1989.080270328
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  • 4
    Electronic Resource
    Electronic Resource
    Radical polymerization of styrene initiated by styrene-arsenic sulfide complex (1989)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 27 (1989), S. 3811-3816 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Styrene forms a complex with arsenic sulfide which in DMF at 85°C initiates radical polymerization yielding high molecular weight polymer. The order of reaction, with respect to initiator and monomer, is 0.5 ± 0.02 and unity, respectively. The energy of activation for the system computed as 96 kJ mol-1 and the polymerization is retarded by hydroquinone. A possible mechanism for reaction has also been proposed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1989.080271121
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  • 5
    Electronic Resource
    Electronic Resource
    Abortions in free ranging Hanuman langurs (Presbytis entellus) — a male induced strategy? (1988)
    Springer
    Human evolution 3 (1988), S. 297-308 
    Details
    ISSN: 1824-310X
    Keywords: Presbytis entellus ; Reproductive strategies ; Abortion ; Infanticide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During a 10-year long term study, 6 eye-witnessed and 1 pressumed cases of abortions occurred in 3 one-male bisexual troops of free ranging langurs (Presbytis entellus) near Jodhpur, Rajasthan, India. The age of the unborns varied from 35 to about 200 days. The subsequent birth interval ranged between 7.1–21.1 months. 2 miscarriages occurred during stable periods of residency of a single male. 5 cases occurred prior to or after infanticide in connection with male changes. In one case a female was attacked by the new male before she aborted. In one case a female presumably aborted after attacks on her semiweaned infant. Most of the reproductive losses hence seem to be related to psychical and physical stress exerted by new males on pregnant females. As part of their reproductive strategy, males reduce their waiting time to insemination in this way. Abortions may likewise represent an adaptive reproductive strategy of females, who prefer to abort instead of investing in a foetus which is likely to be killed after birth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02435859
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  • 6
    Electronic Resource
    Electronic Resource
    Studies on the polymerization of methyl methacrylate using ylide as an initiator and degradative transfer agent (1986)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 141 (1986), S. 103-111 
    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 mit α-Picolinium-p-chlorphenacylid initiierte Polymerisation von Methylmethacrylat in Tetrachlorkohlenstoff bei 30, 35 und 40°C und einer Dauer von vier Stunden wurde dilatometrisch untersucht. Die Reaktionsordnungen im Hinblick auf die Konzentration von Ylid und Methylmethacrylat liegen bei 0,22 ± 0,1 bzw. 1,0. Die gesamte Aktivierungsenergie und der mittlere Wert von kp2/kt beträgt 21 kJ · mol-1 bzw. 0,37 · 10-2.Die Ergebnisse wurden als radikalische Polymerisation mit einer initiatorabhängigen Übertragung und einem bimolekularen Abbruch erklärt.
    Notes: The polymerization of methyl methacrylate (MMA) initiated by α-picolinium-p-chlorophenacylide in CCl4 at 30, 35, and 40°C for four h was investigated dilatometrically. The orders of reaction with respect to the concentrations of ylide and MMA are 0.22 ± 0.01 and 1.0, respectively. The overall energy of activation and an average value of kp2/kt are 21.0 kJmol-1 and 0.37 ± 10-2, respectively. The results are explained in terms of radical mode of polymerization with initiator dependent transfer besides bimolecular termination.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1986.051410111
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  • 7
    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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  • 8
    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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  • 9
    Electronic Resource
    Electronic Resource
    Radical polymerization of methyl methacrylate initiated by styrene/arsenic sulfide complex (1989)
    Basel : Wiley-Blackwell
    Die Makromolekulare Chemie, Rapid Communications 10 (1989), S. 589-593 
    Details
    ISSN: 0173-2803
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1989.030101105
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  • 10
    Electronic Resource
    Electronic Resource
    Effect of imidazolium-p-chlorophenacylide on the radical copolymerization of methyl methacrylate with styrene (1987)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 38 (1987), S. 244-247 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die radikalische Copolymerisation von Methylmethacrylat und Styren mit Imidazolium-p-chlorphenacylid (ICPY) als Beschleuniger und AIBN als Initiator ergibt alternierende Copolymere, wie durch NMR-Spektroskopie gezeigt wurde. Die Copolymerisationsgeschwindigkeit ist eine direkte Funktion von [ICPY], [MMA] und der Polymerisations-temperatur, während [St] eine umgekehrte Wirkung ausübt. Der Beschleunigungseffekt wird auf die Zunahme der Initiierungsgeschwindigkeit zurückgeführt. Den Polymerisationsgrad beeinflußt das Ylid nicht.
    Notes: Radical copolymerization of methyl methacrylate with styrene using imidazolium-p-chlorophenacylide (ICPY) as accelerator in the presence of AIBN resulted in alternating copolymers as evidenced by NMR spectroscopy. The rate of copolymerization is a direct function of [ICPY], [MMA] and polymerization temperature, but [St] has an inverse effect. The accelerating effect is due to increase of rate of initiation. The ylide does not effect average degree of polymerization.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1987.010380409
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