Dow Corning Corporation

Roberto Bortolin

Bhukandas Parbhoo

Scott S Brown

A method of making silethynyl polymers having units of the general formula--(R.sub.2 SiC.tbd.C)-- wherein each R independently denotes a hydrogen atom, an alkyl, aryl or alkenyl group or a substituted alkyl, aryl or alkenyl group having up to 18 carbon atoms comprises adding a lithium salt of one or more diethynylsilanes of the general formula R.sub.2 Si(C.tbd.CH).sub.2 to one or more dihalosilanes of the general formula R.sub.2 SiX.sub.2 where X is a halogen atom and allowing the components to react. Copolymers with alternating units can be made. Linear polymers are made preferentially. Limiting the use of solvent increases the percentage of linear polymers produced.

Method of making silethynyl polymers

A method of making silethynyl polymers having units of the general formula --(R.sub.2 SiC.tbd.C)-- wherein each R independently denotes a hydrogen atom, an alkyl, aryl or alkenyl group or a substituted alkyl, aryl or alkenyl group having up to 18 carbon atoms comprises adding a lithium salt of one or more diethynylsilanes of the general formula R.sub.2 Si(C.tbd.CH).sub.2 to one or more dihalosilanes of the general formula R.sub.2 SiX.sub.2 where X is a halogen atom and allowing the components to react. Copolymers with alternating units can be made. Linear polymers are made preferentially. Limiting the use of solvent increases the percentage of linear polymers produced.

A method of making silethynyl-siloxane copolymers having R.sub.2 SiC.tbd.C units and R.sub.2 SiO units wherein each R denotes H or a C.sub.1-16 hydrocarbon or substituted hydrocarbon group, comprises ring-opening copolymerization in the presence of a catalytic amount of a lithium compound, of cyclic siloxanes and cyclic silethynyl polymers. Novel silethynyl-siloxane copolymers of the formula ##STR1## are also disclosed wherein R' denotes --C.tbd.CH or R and a and b are at least 1.

Method of making silethynyl-siloxane copolymers

Organosilbutadiyne polymers having the general formula R'-[(R).sub.2 Si--C.tbd.C--C.tbd.C].sub.n -(R).sub.2 SiR' wherein R is a hydrogen atom, a hydrocarbon group or a substituted hydrocarbon group, R' is hydroxyl, halogen or R and n is an integer, are made by (A) reacting HC.tbd.C--C.dbd.CH--OZ with alkyllithium in a molar ratio of 1:3 wherein Z denotes an alkyl group having up to 6 carbon atoms followed by (B), further reacting the product of (A) with one or more dihalosilanes.

Method of making organosilbutadiyne polymers

Organosilbutadiyne polymers having the general formula R'-[(R).sub.2 Si-C.tbd.C-C.tbd.C].sub.n -(R).sub.2 SiR' wherein R is a hydrogen atom, a hydrocarbon group or a substituted hydrocarbon group, R' is hydroxyl, halogen or R and n is an integer, are made by (A) reacting bis(trialkylsilyl)butadiyne with alkyllithium in a molar ratio of 1:2 followed by (B), further reacting the product of (A) with one or more dihalosilanes.

Polysilanes of the general formula (RSi).sub.n wherein R is an alkyl, aryl, alkaryl or aralkyl group having 4 to 18 carbon atoms and where n has a value of at least 8, are soluble in a liquid organic medium when R is a stearically hindered or large group. Compositions comprising the organic liquid medium and dissolved therein the polysilane are also described.

Polysilanes

Cyclic silethynyl polymers, having at least 4 silicon atoms per polymer, have the average formula ##STR1## Preferably x has a value of 5 or 6, and each R is independently methyl or phenyl. They are prepared by reacting a lithium salt of one or more diehtynylsilanes with one or more dihalosilanes. These polymers are useful for example in semi- or photoconductive applications.

Cyclic silethynyl polymers and a method for making them

A process for preparing polysilanes of the general formula (RSi).sub.n wherein each R denotes independently an alkyl, aryl, alkaryl or aralkyl group having from 1 to 18 carbon atoms and n is at least 8, comprises reacting at least one silane of the general formula RSiX.sub.3 wherein R is as defined above and X denotes a halogen atom with an alkali metal in an organic liquid medium in which the silane is soluble, preferably tetrahydrofuran.

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Barry, United Kingdom

Roberto Bortolin