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  • 1
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 1431-1442 
    ISSN: 0887-624X
    Keywords: poly(silmethylene) ; in situ polymerization ; polymer blend ; thermal stability ; dynamic mechanical properties ; graft copolymers ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(diphenylsilmethylene) (PDPSM)/poly(methylphenylsilmethylene) (PMPSM) binary polymer blends were synthesized by in situ ring-opening polymerization of 1,1,3,3-tetraphenyl-1,3-disilacyclobutane in PMPSM. Three catalytic methods as well as a noncatalytic method were employed. Radical initiators such as an organic peroxide or azo-compound proved to be the effective catalysts in addition to copper compounds. Blend samples were characterized in detail by DSC, dynamic mechanical analysis, solvent extraction, and microscopic observation to clarify the relationship between the preparative method and the properties of these polymer blends. It is strongly suggested that a part of PMPSM is converted into an insoluble form via formation of PDPSM-PMPSM block or graft copolymers in the case of the in situ copper-catalyzed polymerization in xylene. The formation of block or graft copolymers is also suggested for samples prepared by the in situ bulk polymerization in the presence of a radical initiator. However, PMPSMs simultaneously underwent molecular weight decrease and insolubilization probably due to polymer chain scission and crosslinking, respectively, when the latter method was employed using PMPSM with very high molecular weight. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1431-1442, 1997
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 399-405 
    ISSN: 0887-624X
    Keywords: poly(diphenylsilmethylene) ; in situ polymerization ; polymer blends ; ring-opening polymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The in situ polymerization of 1,1,3,3-tetraphenyl-1,3-disilacyclobutane with or without a catalyst in flexible organo-silicon polymers was demonstrated to provide poly(silmethylene)-based polymer blends. An alternative route, which implies preparation of blends via synthesis of a flexible polymer in the presence of a rigid polymer, was also promising. The resulting polymer blends were characterized by DSC, dynamic mechanical analysis, and solvent extraction. No chemical interaction is observed between component polymers of blends prepared by the in situ bulk polymerization method while formation of block or graft copolymers comprising poly(diphenylsilmethylene) and flexible polymers is suggested when in situ copper-catalyzed polymerization was employed. A morphological difference between samples synthesized by the different methods was suggested by microscopic observation. © 1997 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 36 (1998), S. 755-761 
    ISSN: 0887-6266
    Keywords: positron annihilation lifetime spectroscopy ; free volume ; transition temperatures ; poly(silylenemethylene)s ; dynamic mechanical analysis ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Amorphous and crystalline poly(silylenemethylene)s with the repeating PhRSiCH2 (R : Me or Ph) units were characterized by positron annihilation lifetime spectroscopy (PALS) to gain insights into the molecular motions of these polymers. The temperature dependence of the ortho-positronium lifetime (τ3) and intensity (I3) was examined from 50 to 470 K for each sample. The glass transition temperature of each polymer was easily distinguished by a change in the slope of τ3 spectrum. Both polymers exhibited a steep drop of I3 at 130-140 K being probably assignable to the transition arising from the motions of phenyl groups, which was almost undetectable by means of differential scanning calorimetry or dynamic mechanical analysis. Several other transitions of these polymers detected by PALS are also discussed. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 755-761, 1998
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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