Ge- and Sn-containing poly(p-xylylene): synthesis, structure and thermal behavior

Autor: Valeria I. Rozenberg, Leonid I. Trakhtenberg, E. V. Nikolaeva, Henning Hopf, Genrikh N. Gerasimov, Sergei N. Chvalun, E. I. Grigoriev, Elena L. Popova
Rok vydání: 1998
Předmět:
Zdroj: Macromolecular Chemistry and Physics. 199:2179-2184
ISSN: 1521-3935
1022-1352
Popis: Block copolymers of unsubstituted poly(p-xylylene)(PPX) and Ge- or Sn-organic bridged PPX (GePPX and SnPPX) were prepared by pyrolysis of specially synthesized organometallic p-cyclophane precursors followed by deposition and polymerization of the thus produced p-xylylene monomers. The copolymer structure and thermal behavior were investigated depending on deposition temperature (10 and -196°C). The copolymer PPX-GePPX obtained from solid monomers deposited at -196 C (2a) consists of long quasi-independent PPX and GePPX blocks and has paracrystalline structure. Thermal treatment of 2a near 160°C yields crystalline regions of PPX along with paracrystalline aggregates of GePPX. Pyrolysis of this system near 300°C in an inert atmosphere results in the formation of Ge crystals in PPX matrix. In contrast, the copolymer PPX-GePPX produced by simultaneous deposition and polymerization at 10°C (2a') contains shorter blocks of PPX and GePPX than the copolymer deposited at -196°C, Copolymer 2a' turns to the amorphous state during thermal treatment, and its pyrolysis does not lead to Ge-crystal formation; hence the supramolecular structure of the polymer plays an important role in inorganic phase formation. The copolymer PPX-SnPPX (2b) is formed only at a deposition temperature of-196°C; deposition at 10°C yields oligomeric resins. The structure of 2b is nearly the same as that of 2a; pyrolysis of 2b in air results in SnO 2 -crystal formation in a PPX matrix.
Databáze: OpenAIRE
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