ISSN:
0941-1216
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
„One-Pot“ Syntheses, Modifications and Applicabilities of Poly(carbosilanes)The modification of poly(carbosilanes) and the investigation of their application as binding agents and sintering additives in the production of pressurelessly sintered SiC-bulks as well as their effectiveness as precursors for SiC-fibers is of considerable interest. The synthesis of suitable compounds considers the variation of the carbosilane bridge, the following reactions of functional groups, the backbone branching at silicon and carbon atoms, and the insertion of heteroelements, especially boron and titanium. Different synthetic routes were used for the preparation of modified phenyl-containing poly(carbosilanes). The pyrolytic method, developed by YAJIMA and coworkers, transformed the methyl-containing poly(silanes) into poly(carbosilanes). The addition of polyborodiphenylsiloxane gave products with boron in the molecular sceleton. The development of a one step synthesis in analogy to the Wurtz-polycondensation leads to a series of methylene- and phenylethylene-bridged oligomeric compounds. Furthermore, branched and the heteroelements boron- and titanium-containing poly(carbosilanes) were obtained. The substitution of the functional phenyl groups leads to halogenated and alkyl-, alkenyl-, as well as alkynyl-substituted oligomers. Modified poly(carbosilanes) with unsaturated functional groups or SiH were prepared via Grignard-coupling. Beside benzylidene the units diphenylmethylene, p-xylylene and p-phenylene were used as carbosilane bridges. Directly synthesized copolymers were applicable as binding agents and sintering additives for the production of pressurelessly sintered SiC-bulks. Ethynyl-substituted poly(carbosilanes) were used as precursors for the production of oxygen-free SiC-fibers.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/prac.19963380143
