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  • 11
    Digitale Medien
    Digitale Medien
    New telechelic polymers and sequential copolymers by polyfunctional initiator-transfer agents (INIFERS) (1982)
    Springer
    Polymer bulletin 8 (1982), S. 319-324 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Linear and three-arm star hydroxy-telechelic polyisobutylenes have been quantitatively esterified with pyromellitic dianhydide in the presence of 4-N,N′-dimethylaminopyridine in tetrahydrofuran at room temperature. Chain extension occurred only under reflux conditions (67°C). In the presence of chromium acetyl acetonate catalyst at 140°C insoluble networks were obtained within minutes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00264920
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  • 12
    Digitale Medien
    Digitale Medien
    New telechelic polymers and sequential copolymers by polyfunctional initiator-transfer agents (inifers) (1983)
    Springer
    Polymer bulletin 9 (1983), S. 570-576 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary The synthesis and characterization of linear telechelic polyisobutylenes having propargyl ether, propargyl ester and propiolic ester end groups are described. The syntheses were accomplished by reacting α, ω-di (hydroxy)-polyisobutylene with propargyl bromide or phthalic anhydride followed by propargylic alcohol or monopropargylic ester of phthalic acid chloride, or propiolic acid in the presence of different catalysts at room temperature (see Scheme 2). According to IR and 1H-NMR analyses quantitative conversions were obtained.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00307880
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  • 13
    Digitale Medien
    Digitale Medien
    Synthesis, characterization and diels-alder extension of cyclopentadiene telechelic polyisobutylene (1983)
    Springer
    Polymer bulletin 9 (1983), S. 268-275 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Abstract The use of 1-chlorodicyclopentadiene (DCp-Cl) as a minifer for the polymerization of isobutylene leading to asymmetric telechelic polymers having dicyclopentadienyl head groups and t-chloro tail groups, has been investigated. BCl3 is ineffective, however, diethylaluminum chloride was found to be a suitable coinitiator for the polymerization. According to kinetic investigations chain transfer to monomer is absent and DCp-Cl is an efficient minifer. Polymer characterization indicated a DCp functionality close to 1.0. The t-chloro functionality was 0.27, probably due to side reactions of the t-chloro group with the strong Lewis acids formed during the polymerization.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00262718
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  • 14
    Digitale Medien
    Digitale Medien
    Silica grafted polyisobutylene and butyl rubber (1982)
    Springer
    Polymer bulletin 6 (1982), S. 401-407 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Silica surfaces have been modified by reaction with Cl-Si(CH3)2-CH2-CH2-C6H4-CH2Cl and the modified solids were subsequently used in conjunction with Et2AlCl or AlMe3 coinitiators to initiate the surface graft copolymerization of isobutylene-isoprene mixtures. The experimental conditions have been chosen such that the composition of the rubbery component of the surface-graft be close to that of commercial butyl rubber. The overall composition of silica-grafted butyl rubbers have been characterized.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00959850
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  • 15
    Digitale Medien
    Digitale Medien
    Polyisobutylene model elastomers prepared using demonstrably complete end-linking reactions (1983)
    Springer
    Polymer bulletin 9 (1983), S. 375-381 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Linear polyisobutylene (PIB) molecules with either hydroxyl or isopropenyl groups at the chain ends were prepared using cationic polymerizations with bifunctional initiator-chain transfer agents. Extensive spectroscopic analyses confirmed the essentially perfect difunctionality of the two types of polymers. The former polymers were end-linked using an aromatic triisocyanate, and the latter by means of a tetrafunctional silane. The resulting trifunctional and tetrafunctional model PIB networks were found to have absolutely negligible sol fractions, which demonstrates that the end-linking reactions used to prepare them were essentially complete. The networks were studied with regard to their equilibrium stress-strain isotherms in uniaxial extension at 25 °C. The results thus obtained are in satisfactory agreement with theory and yield no evidence whatever for significant elastic contributions from inter-chain entanglements.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00265316
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  • 16
    Digitale Medien
    Digitale Medien
    Preparation of poly(vinyl chloride-g-isobutylene) by BCl3 (1979)
    Springer
    Polymer bulletin 1 (1979), S. 253-258 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Poly(vinyl chloride-g-isobutylene) has been synthesized using mildly dehydrochlorinated (NaOH treated) PVC in conjunction with BCl3 coinitiator. Treatment of PVC with NaOH increases initial thermal dehydrochlorination rate and renders the polymer suitable for efficient grafting. Untreated PVC produces negligible grafting.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00254333
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  • 17
    Digitale Medien
    Digitale Medien
    New telechelic polymers and sequential copolymers by polyfunctional initiator transfer agents (inifers) (1985)
    Springer
    Polymer bulletin 13 (1985), S. 97-102 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Three-arm star polyisobutylenes carrying tert.-chlorine end groups and a phenyl ring at the center of the star (see formula II in the Introduction) have been prepared by a continuous polymerization process. Thus into a stirred glass reactor were fed continuously a mixed feed of monomer plus trinifer (TCC) and a separate feed of BCl3 coinitiator in methyl chloride solvent at −40°C, and the product plus unreacted ingredients were removed continuously. Stationary conditions were maintained by keeping the rates of input and output (i.e., volumes) equal and constant. After a short induction phase (∼2–3 residence times) telechelic polymers of essentially theoretical number average end functionalities (¯Fn=3.0+0.1), close to theoretical molecular weights (¯Mn) and molecular weight distributions were obtained. The polymerization kinetics are discussed and compared to that of an earlier semicontinuous process used for the routine synthesis of telechelic polyisobutylenes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00254216
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  • 18
    Digitale Medien
    Digitale Medien
    New telechelic polymers and sequential copolymers by polyfunctional initiator-transfer agents (inifers) (1983)
    Springer
    Polymer bulletin 10 (1983), S. 31-38 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary α, ω-Di (nitrile)polyisobutylenes (nitrile-telechelic polyisobutylenes) have been synthesized by reacting α, ω-di (hydroxy) polyisobutylenes (hydroxyl-telechelic polyisobutylenes) with acrylonitrile, p-cyanobenzoyl chloride, p-cyanobenzoic acid and p-cyanobenzyl chloride by the use of a variety of catalysts, e.g. N-benzyltrimethylannnonium hydroxide, 4-N,N′-dimethylaminopyridine, dicyclohexylcarbodiimide, tetrabutylammonium hydrogen sulfate and tricaprylymethylammonium chloride. IR and 1H-NMR analyses of models and polymer products suggest quantitative functionalization, except with p-cyanobenzyl chloride where only ∼ 80% functionalization was achieved. Methanesulfonation of the polymer-diol with methanesulfonyl chloride followed by reaction with NaCN in the presence of tricaprylymethylammonium chloride phase transfer catalyst gave quantitatively α, ω-di (nitrile) polyisobutylene.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00263235
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  • 19
    Digitale Medien
    Digitale Medien
    Polyisobutylene model elastomers prepared using demonstrably complete end-linking reactions (1984)
    Springer
    Polymer bulletin 11 (1984), S. 19-24 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Cationic polymerizations with a trifunctional initiator-chain transfer agent were used to prepare three-arm polyisobutylene [C(CH3)2CH2] (PIB) molecules with hydroxyl groups at all three chain ends. Extensive spectroscopic analyses confirmed the essentially perfect trifunctionality of the polymers, which were then end-linked using an aromatic diisocyanate to give trifunctional model networks. The PIB elastomers were found to have negligible sol fractions, which demonstrates that the end-linking reactions used to prepare them were essentially complete. They were studied, swollen, with regard to their equilibrium stressstrain isotherms in uniaxial extension at 25°C. As was found to be the case for trifunctional and tetrafunctional PIB networks prepared from the linear chains, the results were in satisfactory agreement with theory and yielded no evidence that inter-chain entanglements contribute to the modulus at elastic equilibriums.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00401709
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  • 20
    Digitale Medien
    Digitale Medien
    Living carbocationic polymerization (1986)
    Springer
    Polymer bulletin 15 (1986), S. 317-323 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Abstract A new family of initiating systems has been discovered that efficiently induces the truly living polymerization of isobutylene (IB). The initiating systems are complexes of organic tertiary esters e.g., cumyl acetate, 2,4,4-trimethylpentane-2-acetate, with BCl3. Living polymerizations proceed very rapidly in a variety of solvents, i.e., CH3Cl, CH2Cl2, C2H5Cl, and mixtures of chlorinated solvents plus n-hexane, in the range from −10° to −50°C. The living nature of the polymerizations was demonstrated by linear ¯Mn versus WPIB (g of polymer formed) plots starting at the origin and horizontal N (number of PIB chains) versus WPIB plots. The DPn of the products obeys [Mo]/[Io] where [Mo] and [Io] are initial monomer and initiator concentrations, respectively. Conversions and initiator efficiencies are ∼100%. In carefully controlled experiments narrow molecular weight distribution polyisobutylenes (PIB) have been obtained, i.e., Mw/Mn=1.17 − 1.3. A mechanism is outlined that helps rationalize the findings. It is postulated that the living polymerization of IB initiated by organic tertiary ester·BCl3 complexes most likely proceeds by a two-component group transfer polymerization process.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00254850
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