Process for preparing polycarbosilanes and new polycarbosilanes

Claim 2

A process for preparing a polycarbosilane based on structural units corresponding to the formula I ##STR13## wherein R 1 represents hydrogen, alkyl, cycloalkyl, aryl or arylalkyl, whereby R 1 may also have different meanings in different units of one and the same polycarbosilane, R 2 represents alkyl, cycloalkyl, aryl or arylalkyl, whereby R 2 may also have different meanings in different units of one and the same polycarbosilane, and A represents a straight-chain or branched alkylene radical or a cycloalkylene radical, whereby A may also have different meanings in different units of one and the same polycarbosilane, comprising reacting at least one dihalosilane corresponding to the formula II ##STR14## wherein R 1 and R 2 have the meanings given above, and X represents halogen, with at least one dihalo-hydrocarbon corresponding to the formula III Y--A--Y (III) wherein A has the meaning given above and Y represents chlorine, bromine or iodine, in the presence of an alkali metal.

Claim 3

A process according to claim 1, wherein X and Y are each individually selected from the group consisting of chlorine and bromine.

Claim 4

A polycarbosilane based on structural units corresponding to the formula Ia ##STR15## wherein R 1a represents hydrogen, alkyl, cycloalkyl or arylalkyl, whereby R 1a may also have different meanings in different units of one and the same polycarbosilane, R 2a represents alkyl, cycloalkyl or arylalkyl, whereby R 2 ° may also have different meanings in different units of one and the same polycarbosilane, and A represents a straight-chain or branched alkylene radical or a cycloalkylene radical, whereby A may also have different meanings in different units of one and the same polycarbosilane, prepared according to the process of claim 1.

Claim 5

A polycarbosilane based on structural units corresponding to the formula I'. wherein R 1' represents aryl, whereby R 1' may also have different meanings in different units of one and the same polycarbosilane, R 2 represents alkyl, cycloalkyl, aryl or arylalkyl, whereby R 2 may also have different meanings in different units of one and the same polycarbosilane, and A represents a straight-chain or branched alkylene radical or a cycloalkylene radical, whereby A may also have different meanings in different units of one and the same polycarbosilane.

Claim 6

A polycarbosilane based on structural units corresponding to the formula I'. wherein R 1' represents aryl, whereby R 1' may also have different meanings in different units of one and the same polycarbosilane, R 2 represents alkyl, cycloalkyl, aryl or arylalkyl, whereby R 2 may also have different meanings in different units of one and the same polycarbosilane, and A represents a straight-chain or branched alkylene radical or a cycloalkylene radical, whereby A may also have different meanings in different units of one and the same polycarbosilane.

Claim 7

A modified polycarbosilane according to claim 4, wherein up to 50% of the structural units of formula I' are replaced by structural units corresponding to the formula Ib ##STR16## wherein R 1b represents alkyl, cycloalkyl or arylalkyl, whereby R 1b may also have different meanings in different units of one and the same polycarbosilane, R 2b represents alkyl, cycloalkyl or arylalkyl, whereby R 2b may also have different meanings in different units of one and the same polycarbosilane, and A has the meanings given in claim 4.

Claim 8

A polycarbosilane according to claim 4, wherein A is the same in all the structural units of the polycarbosilane.

Claim 9

A polycarbosilane according to claim 5, wherein A is the same in all the structural units of the polycarbosilane.

Claim 10

A polycarbosilane according to claim 4, wherein the substituent R 2 is the same in all structural units of the polycarbosilane, and the substituent R 1' is the same in all structural units of the polycarbosilane.

Claim 11

A polycarbosilane according to claim 6, wherein the substituent R 2 is the same in all structural units of the polycarbosilane, and the substituent R 1' . is the same in all structural units of the polycarbosilane.

Claim 12

A polycarbosilane according to claim 5, wherein the substituents R 2 and R 1' each have only a single meaning in all structural units of the polycarbosilane corresponding to formula I', and the substituents R 2b and R 1b each have only a single meaning in all structural units of the polycarbosilane corresponding to formula Ib.

Claim 13

A polycarbosilane according to claim 7, wherein the substituents R 2 and R 1' each have only a single meaning in all structural units of the polycarbosilane corresponding to formula I', and the substituents R 2b and R 1b each have only a single meaning in all structural units of the polycarbosilane corresponding to formula Ib.

Claim 14

A polycarbosilane according to claim 4, wherein R 2 represents an aryl group.

Claim 15

A polycarbosilane according to claim 12, wherein R 2 represents a phenyl group.

Claim 16

A polycarbosilane according to claim 12, wherein the substituents R 2 and R 1' are identical.

Claim 17

A polycarbosilane according to claim 14, wherein the substituents R 2 and R' are each phenyl.

Claim 18

A polycarbosilane according to claim 5, wherein at least one of R 1b and R 2b represents a lower alkyl group.

Claim 19

A polycarbosilane according to claim 16, wherein said lower alkyl group is selected from the group consisting of methyl, ethyl, propyl and butyl.

Claim 20

A polycarbosilane according to claim 4, wherein A represents a straight-chain or branched C1- to C6-alkylene group or a C4- to C7-cycloalkylene group.

Claim 21

A polycarbosilane according to claim 5, wherein A represents a straight-chain or branched C1- to C6-alkylene group or a C4- to C7-cycloalkylene group.

Claim 22

A polycarbosilane according to claim 18, wherein A represents a C1- to C3-alkylene group selected from the group consisting of methylene, ethylene, and linear or branched propylene.

Claim 23

A polycarbosilane according to claim 19, wherein A represents a C1- to C3-alkylene group selected from the group consisting of methylene, ethylene, and linear or branched propylene.

Claim 24

A polycarbosilane according to claim 18, wherein A represents a cycloalkylene group selected from the group consisting of cyclopentylene and cyclohexylene.

Claim 25

A polycarbosilane according to claim 19, wherein A represents a cycloalkylene group selected from the group consisting of cyclopentylene and cyclohexylene.

Claim 26

A polycarbosilane according to claim 4, wherein said polycarbosilane has a proportion of Si--Si bonds of at most 5%.

Claim 27

A polycarbosilane according to claim 5, wherein said polycarbosilane has a proportion of Si--Si bonds of at most 5%.

Claim 28

A polycarbosilane according to claim 4, wherein said polycarbosilane is formed of molecules containing an average number of structural units between 10 and 500.

Claim 29

A polycarbosilane according to claim 5, wherein said polycarbosilane is formed of molecules containing an average number of structural units between 10 and 500.

Claim 30

A polycarbosilane according to claim 26, wherein the molecules of said polycarbosilane contain an average number of structural units between 30 and 150.

Claim 31

A polycarbosilane according to claim 27, wherein the molecules of said polycarbosilane contain an average number of structural units between 30 and 150.

Claim 32

A polycarbosilane according to claim 4, wherein said polycarbosilane has an average molecular weight in the range from 580 to 300,000 g/mol.

Claim 33

A polycarbosilane according to claim 5, wherein said polycarbosilane has an average molecular weight in the range from 580 to 300,000 g/mol.

Claim 34

A polycarbosilane according to claim 4, further comprising up to 50% branched structural units corresponding to at least one of the formulae IV or V ##STR17## wherein A has the meaning given in claim 4, and R represents hydrogen, alkyl, cycloalkyl, aryl or arylalkyl.

Claim 35

A polycarbosilane according to claim 5, further comprising up to 50% branched structural units corresponding to at least one of the formulae IV or V ##STR18## wherein A represents a straight-chain or branched alkylene radical or a cycloalkylene radical, whereby A may also have different meanings in different units of one and the same polycarbosilane, and R represents hydrogen, alkyl, cycloalkyl, aryl or arylalkyl.

Claim 36

A polycarbosilane according to claim 4, wherein said polycarbosilane carries mono-reacted terminal groups selected from the group consisting of R 1a R 2a Si(X)-- and R 1' R 2 Si(X)--halosilyl groups, Y--A-- halo-hydrocarbon groups, R 1a R 2a Si(OH)-- and R 1' R 2 Si(OH)-- hydroxysilyl groups, R 1a R 2a Si(O-alkyl)-- and R 1' R 2 Si(O-alkyl)- alkoxysilyl groups, and trialkylsilyl and lower alkyl chain-terminating groups, wherein R 1a represents hydrogen, alkyl, cycloalkyl or arylalkyl, whereby R 1a may also have different meanings in different units of one and the same polycarbosilane, R 2a represents alkyl, cycloalkyl or arylalkyl, whereby R 2a may also have different meanings in different units of one and the same polycarbosilane, X represents halogen, Y represents iodine, bromine or chlorine, and R 1' , R 2 and A have the meanings given in claim 4.

Claim 37

A polycarbosilane according to claim 34, wherein said terminal groups are selected from the group consisting of R 1b R 2b Si(X)-- halosilyl groups, Y--A-- halohydrocarbon groups, R 1b R 2b Si(OH)-- hydroxysilyl groups, R 1b R 2b Si(O-alkyl)- alkoxysilyl groups, and trialkylsilyl and lower alkyl chain-terminating groups, wherein R 1b represents alkyl, cycloalkyl or arylalkyl, whereby R 1b may also have different meanings in different units of one and the same polycarbosilane, R 2b represents alkyl, cycloalkyl or arylalkyl, whereby R 2b may also have different meanings in different units of one and the same polycarbosilane, and A represents a straight-chain or branched alkylene radical or a cycloalkylene radical, whereby A may also have different meanings in different units of one and the same polycarbosilane, and X and Y have the meanings given in claim 34.

Claim 38

A polycarbosilane according to claim 5, wherein said polycarbosilane carries mono-reacted terminal groups selected from the group consisting of R 1a R 2a Si(X)-- and R 1' R 2 Si(X)-- halosilyl groups, Y--A-- halo-hydrocarbon groups, R 1a R 2a Si(OH)-- and R 1' R 2 Si(OH)-- hydroxysilyl groups, R 1a R 2a Si(O-alkyl)- and R 1' R 2 Si(O-alkyl)- alkoxysilyl groups, and trialkylsilyl and lower alkyl chain-terminating groups, wherein R 1a represents hydrogen, alkyl, cycloalkyl or arylalkyl, whereby R 1a may also have different meanings in different units of one and the same polycarbosilane, R 2a represents alkyl, cycloalkyl or arylalkyl, whereby R 2a may also have different meanings in different units of one and the same polycarbosilane, X represents halogen, Y represents iodine, bromine or chlorine, and R 1' represents aryl, whereby R 1' may also have different meanings in different units of one and the same polycarbosilane, R 2 represents alkyl, cycloalkyl, aryl or arylalkyl, whereby R 2 may also have different meanings in different units of one and the same polycarbosilane, and A represents a straight-chain or branched alkylene radical or a cycloalkylene radical, whereby A may also have different meanings in different units of one and the same polycarbosilane.

Claim 39

A polycarbosilane according to claim 36, wherein said terminal groups are selected from the group consisting of R 1b R 2b Si(X)- halosilyl groups, Y--A-- halohydrocarbon groups, R 1b R 2b Si(OH)- hydroxysilyl groups, R 1b R 2b (Si(O-alkyl)- alkoxysilyl groups, and trialkylsilyl and lower alkyl chain-terminating groups, wherein R 1b represents alkyl, cycloalkyl or arylalkyl, whereby R 1b may also have different meanings in different units of one and the same polycarbosilane, R 2b represents alkyl, cycloalkyl or arylalkyl, whereby R 2b may also have different meanings in different units of one and the same polycarbosilane, and A represents a straight-chain or branched alkylene radical or a cycloalkylene radical, whereby A may also have different meanings in different units of one and the same polycarbosilane, and X and Y have the meanings given in claim 36.