Composition, preparation of polycarbosilanes and their uses

A method for preparing a carbosilane copolymer having a general formula:

• [Si(˜)RC(˜)H]xn[SiR1R2CH2]yn,
• where
• n is the degree of polymerization,
• ˜ represents branched chain,
• 0.1≦x<0.8, 0.2≦y<0.9 and x+y=1,
• the method comprising:
• a one-step Grignard reaction in an organic solvent between halocarbosilane co-monomers in the presence of magnesium, wherein the co-monomers have a general formula:
• XpSiRqCHrXs
• where X is a halogen, R is a monovalent hydrocarbon, 1≦p≦3, 0≦q≦2, 1≦r≦2 and 1≦s≦2.

A method for preparing a carbosilane copolymer having a general formula:

• ([Si(˜)RC(˜)H]xn[SiR1R2CH2]yn[SiR3R4CH2]zn
• where
• n is the degree of polymerization,
• ˜ represents branched chain,
• 0.1≦x<0.8, 0≦y<0.8, 0.2≦z<0.8 and x+y+z=1,
• the method comprising:
• a one-step Grignard reaction in an organic solvent between halocarbosilane co-monomers in the presence of magnesium, wherein the co-monomers have a general formula:
• XpSiRqCHrXs
• where X is a halogen, R is a monovalent hydrocarbon, 1≦p≦3, 0≦q≦2, 1≦r≦2 and 1≦s≦2.

A method for preparing a copolymer carbosilane having a general formula:

• [Si(˜)RC(˜)H]xn[SiR1R2CH2]yn,
• where n is the degree of polymerization, ˜ represents branched chain, 0.1≦x<0.8, 0.2≦y<0.9 and x+y=1
• the method comprising:
• a Grignard reaction between halocarbosilanes co-monomers and a reduction reaction to replace a functional group in a resulting copolymer, the halocarbosilane co-monomers having a general formula:
• XpSiRqCHrXs
• where X is a halogen, R is a monovalent hydrocarbon, 1≦p≦3, 0≦q≦2, 1≦r≦2 and 1≦s≦2.

A method for preparing a copolymer carbosilane having a general formula as

• [Si(˜)RC(˜)H]xn[SiR1R2CH2]yn[SiR3R4CH2]zn
• where n is the degree of polymerization, ˜ represents branched chain, 0.1≦x<0.8, 0≦y<0.8, 0.2≦z<0.8 and x+y+z=1
• the method comprising:
• a Grignard reaction between halocarbosilanes co-monomers and a reduction reaction to replace a functional group in a resulting copolymer, the halocarbosilane co-monomers having a general formula:
• XpSiRqCHrXs
• where X is a halogen, R is a monovalent hydrocarbon, 1≦p≦3, 0≦q≦2, 1≦r≦2 and 1≦s≦2.

A method for preparing a polycarbosilane having a general formula:

• [Si(˜)RC(˜)H]xn[SiR1R2CH2]yn,
• where
• n is the degree of polymerization,
• ˜ represents branched chain,
• 0.1≦x<0.8, 0.2≦y<0.9 and x+y=1
• the method comprising a partial methoxylation of a trihalocarbosilane, a Grignard reaction of the partially methoxylated trihalocarbosilane and a reduction of the partially methoxylated trihalocarbosilane.

A method for preparing a polycarbosilane having a general formula:

• [Si(˜)RC(˜)H]xn[SiR1R2CH2]yn[SiR3R4CH2]zn
• where
• n is the degree of polymerization,
• ˜ represents branched chain,
• 0.1≦x<0.8, 0≦y<0.8, 0.2≦z<0.8 and x+y+z=1,
• the method comprising a partial methoxylation of a trihalocarbosilane, a Grignard reaction of the partially methoxylated trihalocarbosilane and a reduction of the partially methoxylated trihalocarbosilane.