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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 4 (1993), S. 12-16 
    ISSN: 1042-7147
    Keywords: Cationic oxidative polymerization ; MNDO-PM3 ; Phenyltrimethylsilane ; Poly(phenylene sulfide) ; Sulfur chloride ; HOMO ; 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
    Notes: Phenyltrimethylsilane possesses a higher HOMO energy (-9.34 eV) than nonsubstituted benzene (〉0.41 eV). The π electron of the phenyltrimethylsilane localizes on the benzene ring at the ipso position rather than at the para position. Two center energies calculated by the MNDO-PM3 method indicate that the C—Si bond is facilitated to cleave in comparison with the C—H (para position) one of the benzene ring. Phenyltrimethylsilane and phenyl bis(trimethylsilane) were polymerized with sulfur chloride through the cationic oxidative polymerization. The product is isolated as oligo(p-phenylene sulfide), with a melting point of 150-190°C. An electrophile attacks the carbon atom linked to the Si atom in phenyltrimethylsilane. The new synthetic route of PPS can be established on the basis of the computational calculation.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1042-7147
    Keywords: Cationic oxidative polymerization ; Diphenyl disulfide ; AM1 ; π-Frontier electron density ; Poly(phenylene sulfide)s ; 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
    Notes: Substituent groups of the diphenyl disulfides (DPSs) influence the cationic oxidative polymerization in the formation of polyphenylene sulfides (PPSs). A semiempirical MO calculation (AM1) was performed on the model compounds of PPS, such as thioanisoles (TAs) and diphenyl sulfides (PSs), in order to elucidate the reactivity of the cation. Linear PPS is formed on polymerization because of the high electron density of the carbon in the para position. The ratios of the frontier electron density of the carbon in the para position on the disulfide to the sulfur atom are ordered as follows; 3,5-dimethyl-PS〉2,5-dimethyl-PS-3-methyl-PS〉nonsubstituted PS〉2-methyl-PS〉2,6-dimethyl-PS. The formation energies of the σ-complex, which is the intermediate of the reaction, also shows the same order. The theoretical calculation indicates that 3,5-dimethyl disubstituted disulfide and 3-methyl one are most preferable monomers of this cationic oxidative polymerization.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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