Organopolyarylsilanes, process for manufacturing the same and fi

Details Organopolyarylsilanes, process for manufacturing the same and fi Organopolyarylsilanes, process for manufacturing the same and fi

1987-11-06

1989-11-07

Marquis, Melvyn I.

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Mixing of two or more solid polymers; mixing of solid...

501 88, 501 90, 501 95, 264 292, 264 59, 528 10, 524 66, C08F28300

Patent

active

048793345

DESCRIPTION:

BRIEF SUMMARY
DESCRIPTION

[Technical field]
The present invention relates to organopolyarylsilanes comprising aromatic rings in the main chain, particularly, co-pyrolytic condensates of a polysilane and a pitch; a process for manufacturing the same; and novel SiC--C based continuous inorganic fibers produced by spinning such an organopolyarylsilane into fibers and then after infusibilizing, heat-treating the fibers under a non-reactive atmosphere.
[Background art]
Polysilanes are compounds having a skeleton composed of Si--Si linkages. As the polysilanes having organic groups are converted by pyrolysis into polymers having SiC--C linkages in the skelton which are further converted into SiC, that is, an inorganic compound, they have been used as a starting material for SiC, while pitches have been used as a starting material for various carbon articles.
In hitherto known processes for synthesizing SiC from an organosilicon compound such as organopolysilanes or the like, there is a so-called precursor process wherein a polymer is synthesized and then heat-treated. This process is very advantageous in the case where an organosilicon compound is utilized as a starting material for fibers, binders for various ceramics, films, paints and impregnating agents. Therefore, polysilanes or polycarbosilanes produced therefrom by pyrolytic condensation, have been synthesized. The polysilanes are described, for example, in Ceram. Bull. 62, p. 899, (1983), and the polycarbosilanes obtained by pyrolytic condensation of polysilanes are in the Gazettes of Japanese Patent Application Laid-open Nos. 51-126,300, 52-74,000, 52-112,700, 54-61,299, 57-16,029 and 58-136,626. These organosilicon polymers, i.e., organopolysilanes are used as a precursor for inorganic compounds mainly comprising SiC and, in that case, an excess of carbon always exists in the resulting inorganic compounds. In the case where these polymers are used, notwithstanding this carbon seriously affects the characteristics of the resulting inorganic compounds, yet it has heretofore been impossible to arbitrarily control the carbon content to any desired values. In the meantime, carbon materials obtained by using pitches as a precursor, have excellent characteristics, as represented by carbon fibers, and they are however poor in air-oxidation resistivity. In order to obviate this drawback, extensive researches have been conducted on compounding of carbon and ceramics.
In spite of such circumstances, the reason why there have not so far been any precursors that can provide, by heat treatment, an SiC-carbon composite material having a controlled carbon content is because the polysilanes or polycarbosilanes are poor in compatibility with pitches, so that syntheses of such a composite material have had to depend on a process wherein powder of an inorganic substance is employed.
Further, as hitherto known fibers, there have been continuous fibers whose starting materials are polymers obtained by pyrolytic polymerization of an organosilicon compound, as disclosed in the Gazettes of Japanese Patent Application Laid-open Nos. 51-139,929, 51-130,324, 51-130,325, 51-149,925, 51-149,926, 51-147,623, 51-147,624, 52-1,136, 52-5,321, 52-31,126, 52-103,529, 52-59,724, 52-63,427, 52-70,122, 52-96,237, 52-103,529, 53-103,025 and 54-82,435. In the meantime, carbon fibers are obtainable by using rayons, polyacrylonitriles, pitches or the like, as a starting material. A great many of these fibers, and manufacturing processes and applications thereof have been applied for a patent, and some of them have been industrially under mass-production. However, though the formers are excellent in heat resistance, oxidation resistance and compounding properties with metals, they have had various drawbacks, such as low electroconductivities, that is, a volume resistivity of about 10.sup.2 .OMEGA..multidot.cm, and difficulties in control thereof. Also, in the aspect of mechanical properties, the quality control by changing composition is almost impossible, for example, the control of the tensile modulus of e

REFERENCES:
patent: 4324901 (1982-04-01), West et al.
patent: 4544729 (1985-10-01), Nate et al.
patent: 4618591 (1986-10-01), Okamura et al.
Chemical Dictionary, pp. 300, 301, and 398, Netherlands University Press, V. Amsterdam, 1961.
West et al., Polysilastyrene: Phenylmethylsilane-Dimethylsilane Copolymers as Precursors to Silicon Carbide, Ceramic Bulletin, 62, pp 899-903, (1983).
Hasegawa et al., Synthesis of Precursors for Si-C Fibers by Copyrolysis of Polysilane and Pitch, J. Ceram. Jpn. Inter. Ed., vol 95, (92-96),(1987).

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