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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Macromolecules 26 (1993), S. 5099-5104 
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 446 (2007), S. 778-781 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The development of actuators based on materials that reversibly change shape and/or size in response to external stimuli has attracted interest for some time. A particularly intriguing possibility is offered by light-responsive materials, which allow remote operation without the need for ...
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Radical polymerization of methyl methacrylate (MMA) in the presence of methyl α-(bromomethyl) acrylate yielded poly-(MMA) bearing the 2-methoxycarbonylallyl end group through chain reaction involving bimol ecular termination. The molecular weight of the resultant polymer was effectively controlled with a small amount of the bromomethylacrylate added; the chain transfer constant was estimated to be 0.9. The poly (MMA) with the unsaturated end group ( $$\bar M$$ n= 2800 and $$\bar M$$ w/ $$\bar M$$ n = 1.39) was used as a macromonomer for copolymerization with various monomers. The monomer mixture containing styrene and less than 10 mole-% of the macromonomer produced a corresponding copolymer. Copolymers with non-conjugated monomers were also obtained. The macromonomer was less reactive toward poly (MMA) radical than poly (styrene) radical. The radical produced by an addition of poly (styrene) radical to the macromonomer was detected using ESR spectroscopy at room temperature.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary ESR spectra of polymer radical from fumaric esters bearing different ester alkyl groups were recorded at room temperature and 120°C. Simulation for the spectra with much better resolution at 120°C revealed that the spectra consist of three components differentiated by molecular weight of the polymer radical and that the component corresponding to the highest molecular weight radical increased with increasing total bulkiness of the ester alkyl groups. Gel permeation chromatography of the polymerization mixture exhibited that the radicals corresponding to the respective spectral components repeat propagation to reach high molecular weight prior to termination.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 1551-1559 
    ISSN: 0887-624X
    Keywords: radical copolymerization ; α-(phenoxymethyl)acrylate ; addition-fragmentation reaction ; unsaturated end group ; 1,1-disubstituted ethylene ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Copolymerizations of methyl α-(phenoxymethyl)acrylate (MPMA) with methyl acrylate, methyl methacrylate, styrene, and methyl α-ethylacrylate were carried out. Addition of a polymer radical to MPMA followed by the subsequent fragmentation of poly(MPMA) radical resulted in the 2-methoxycarbonylallyl end group and phenoxy radical in the course of the copolymerization. The extent of the fragmentation determined by 1H-NMR spectroscopy depends on reactivity of the MPMA radical toward the reference monomers. An increase in the addition rate of the MPMA radical to the reference monomer brought about suppression of the fragmentation. The addition of the MPMA radical to styrene seems to be sufficiently fast to prevent the fragmentation. Since the rate of the fragmentation relative to the propagation was considerably accelerated by raising the temperature to 110°C, MPMA can be used as a novel chain transfer agent to control molecular weight and end group at a temperature above 100°C. © 1993 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 3433-3438 
    ISSN: 0887-624X
    Keywords: free radical polymerization ; free radical copolymerization ; 2-substituted acrylic ester ; oligoethylene oxide ; glass transition temperature ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of methyl 2-(ω-methoxyoligoethleneoxymethyl)acrylates, which were synthesized from reactions of methyl 2-bromomethylacrylate with ω-methoxyoligoethylene glycol, was investigated. All these monomers polymerized readily to high molecular weight despite expectation of the considerable steric hindrance against propagation. No influence of ceiling temperature was observed. The 2-(2-methoxyethyleneoxymethyl)acrylate exhibited similar reactivities to methyl 2-alkoxymethylacrylate reported previously in copolymerization with styrene and methyl methacrylate. The homopolymers synthesized, except for those from methyl 2-methoxymethyl- and 2-(2-methoxyethyleneoxymethyl)acrylates, were soluble in water, and all were soluble in benzene. These polymers were thermally less stable than poly(methyl methacrylate) as confirmed by thermogravimetric analysis, and all showed glass transition temperatures below 0°C. © 1993 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2555-2561 
    ISSN: 0887-624X
    Keywords: living polymerization ; radical polymerization ; oxoaminium salt ; nitroxide ; chlorine-attached polystyrene ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An oxoaminium chloride that is prepared by reacting 2,2,6,6-tetramethylpiperidinyl-1-oxy (TEMPO) with chlorine in carbon tetrachloride initiates radical polymerization of styrene at 120°C. In the early stages of polymerization, a monomeric adduct, 2,2,6,6-tetramethyl-1-(2-chloro-1-phenylethoxy)piperidine, is formed. Thereafter, styrene polymerization exhibiting the characteristics of living polymerization proceeds. High molecular weight polymers with relatively narrow molecular weight distributions are obtained by this polymerization. 1H-NMR spectra of the polymers reveal that a chlorine atom and a TEMPO group are present at the α- and ω-termini, respectively. The monomeric adduct was prepared by heating the oxoaminium chloride and styrene in carbon tetrachloride at 65-70°C, and was characterized by 1H- and 13C-NMR spectroscopy. It was found to be suitable as an initiator for nitroxide-mediated radical polymerization of styrene to make polymers with chlorine on the chain end. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2555-2561, 1998
    Additional Material: 4 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 95-108 
    ISSN: 0887-624X
    Keywords: radical polymerization ; α-substituted acrylic ester ; propagation rate constant ; termination rate constant ; ESR spectroscopy ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polymerization and copolymerization of methyl α-(2-carbomethoxyethyl)acrylate (MMEA), which is known as a dimer of methyl acrylate, were studied in relation to steric hindrance-assisted polymerization. The propagating polymer radical from MMEA was detected as a five-line spectrum and quantified by ESR spectroscopy during the bulk polymerization at 40-80°C. The absolute rate constants of propagation and termination (κp and κt) for MMEA at 60°C (κp = 19 L/mol s and κt = 5.1 × 105 L/mol s) were evaluated using the concentration of the propagating radical at the steady state. The balance of the propagation and termination rates allows polymer formation from MMEA. The polymerization rate of MMEA at 60°C was less than that of MMA by a factor of about 4 at a constant monomer concentration. Although no influence of ceiling temperature was observed at a temperature ranging from 40 to 70°C, addition-fragmentation in competition with propagation reduced the molecular weight of the polymer. The content of the unsaturated end group was estimated to be 0.1% at 60°C to the total amount of the monomer units consisting of the main chain. MMEA exhibited reactivities almost similar to those of MMA toward polymer radicals. It is concluded that MMEA is one of the polymerizable acrylates bearing a substituted alkyl group as an α-substituent. Characterization of poly(MMEA) was also carried out. © 1996 John Wiley & Sons, Inc.
    Additional Material: 12 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 197 (1996), S. 901-910 
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Methyl 2-[2,2,2-tris(methoxycarbonyl)ethyl]acrylate and methyl 2-[2,2,2-tris(ethoxycarbonyl)ethyl]acrylate [M(TE)EA] were synthesized for the first time by the reaction of methyl 2-(bromomethyl)acrylate with the corresponding tris(alkoxycarbonyl)methane in the presence of triethylamine at room temperature in 90 and 89% yields, respectively. Attempted homopolymerization of these particular acrylates did hardly occur. However, the radical produced by attack of the primary radical from 2,2′-azo-2,4,4-trimethylpentane at the β-carbon of M(TE)EA was detected via its 5-line ESR spectrum, and a similar spectrum was observed using tert-butyl peroxide as initiator. These findings imply that persistency of the adduct radical of M(TE)EA suppresses further propagation to high molecular weight polymer. Steric congestion of the adduct radical was shown by ESR spectral change at different temperatures. Copolymerization of M(TE)EA with methyl methacrylate proceeded at a slow rate and yielded products containing only 1,7-2,7 units of M(TE)EA per polymer chain irrespective of comonomer composition. When the content of M(TE)EA was lower than 10 mol-% in the monomer mixtures of M(TE)EA with styrene and methyl acrylate, copolymers whose molecular weights decreased with an increase in M(TE)EA content in monomer mixture were obtained. The copolymerization rates were also reduced considerably with increasing content of M(TE)EA in the feed.
    Additional Material: 3 Ill.
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