Molecular Rearrangements of Organosilicon Compounds

Molecular rearrangements of organosilicon compounds

MUCH work has been done on preparing heat-resistant silicon carbide materials in fibrous form, since plastics or metals can be reinforced with them to obtain very heat-resistant material of great mechanical strength. SiC whiskers1 are, however, impractical because of their shortness (several mm), their non-uniform diameter and high cost of production. SiC-on-W (ref. 2) and SiC-on-C (ref. 3) filaments have been produced by chemical vapour methods. These coated filaments are more expensive, and the treatment for making such composite materials requires careful control. We report here on the synthesis of continuous β-SiC fibres by a new process: the conversion of organometallic polymers to inorganic substances. We have studied the transformation process and the structure and mechanical properties of these fibres.

Development of a silicon carbide fibre with high tensile strength

Chemistry of organosilicon compounds

Polycarbosilanes which were synthesized by three methods were melt-spun and cured by heating at low temperatures in air The curing mechanism and the structure of these cured fibres were studied and the relationship between the structure and the pyrolysis process is discussed The structure of the cured fibre is represented by means of five structural elements and the rate of oxidation of the methyl group The pyrolysis process of the cured fibre is discussed in five stages, and the effect of oxygen introduced into polycarbosilane fibre by curing on the pyrolysis process is clarified The structure of the fibre obtained during the pyrolysis process strongly depends on the molecular weight of polycarbosilane

Synthesis of continuous silicon carbide fibre

Siloxanes and/or silcarbanes are emulsion polymerized or copolymerized in the presence of a surface-active sulphonic acid catalyst other than those used in the process of the parent Specification. Sulphonic acids specified are aliphatically substituted naphthalene-, aliphatic-, silylalkyl- and aliphatically substituted diphenyl ether-sulphonic acids, in which the aliphatic substituents contain from 6 to 18 C atoms. If desired, conventional emulsifying agents may be added. Uses.-The emulsions can be used as release agents; pigments and fillers, e.g. silica sol, silica or diatomaceous earth may be added to the emulsions to be used as coating compositions, such as latex paints, or polishes.

Donald R Weyenberg

Papers

Method of polymerizing siloxanes and silcarbanes in emulsion by using a surface active sulfonic acid catalyst

Platinum-Catalyzed Reactions of Silacyclobutanes and 1,3-Disilacyclobutanes

Method of making one component room temperature curing siloxane rubbers

Polyfunctional siloxanes containing terminal alkoxyl groups

Silylene chemistry. I. The thermolysis of methoxypolysilanes