公开(公告)号：DE3852238T2

公开(公告)日：1995-06-14

申请号：DE3852238

申请日：1988-08-04

Applicant: DOW CORNING

Inventor： BURNS GARY THOMAS ,  PU-YUAN LU PAUL ,  ZANK GREGG ALAN

IPC: C04B35/571 ,  C08G77/48 ,  C08G77/60 ,  C04B35/00

Abstract: Halogenated polycarbosilanes are prepared by reacting a polycarbosilane containing at least 0.1 weight percent Si-H groups with a halogenating reagent selected from the group consisting of chlorine, bromine, phosphorous pentachloride, phosphorous pentabromide, antimony pentachloride, N-chlorosuccinimide, N-bromosuccinimide, sulfonyl chloride, and mixtures of CHeXf and a free radical initiator where e is 0 or 1, f is 3 or 4, the sum (e + f) is 4, and X is chlorine or bromine. The halogenated polycarbosilanes can be further treated to produce other derivatized polycarbosilanes. The halogenated and derivatized polycarbosilanes can be converted to silicon carbide containing ceramic materials by pyrolysis at elevated temperatures under an inert atmosphere.

公开(公告)号：FR2656869B1

公开(公告)日：1994-02-25

申请号：FR8909249

申请日：1989-07-10

Applicant: DOW CORNING CORP

Inventor： BURNS GARY THOMAS

IPC: C04B35/571 ,  C08G77/48 ,  C08G77/60 ,  C08G77/18 ,  C08G77/385 ,  C08G77/388 ,  C04B35/64

Abstract: A process for the preparation of a methylpolysilane having a controlled carbon content is provided which includes the steps of heating together to form a reaction mixture at least one alkoxy-functional disilane selected from the group consisting of disilanes having two, three, and four alkoxy groups bonded to the silicon atoms, and mixtures thereof, with either an alkoxy-functional silane having at least one unsaturated substituent or an unsaturated hydrocarbon compound in an amount effective to increase the carbon content of the resulting polymer. The reaction is carried out in the presence of a catalyst which is a source of alkoxide ions. The methylpolysilane polymers produced may be pyrolyzed to form ceramic compositions having increased carbon contents. The ceramics may find use as films, fibers, and coatings, as well as the many other uses to which silicon carbide ceramics have heretofore been put.

公开(公告)号：DE68904877T2

公开(公告)日：1993-08-26

申请号：DE68904877

申请日：1989-10-31

Applicant: DOW CORNING

Inventor： BURNS GARY THOMAS ,  KELLER RONALD JAMES ,  SAHA CHANDAN KUMAR

IPC: C04B35/571 ,  C04B35/575 ,  C04B35/56

Abstract: The preparation of highly densified ceramic bodies by the sintering of certain preceramic polysilazanes filled with silicon carbide powders, metal-containing sintering aids and, optionally, polysilazane curing agents is described. Such highly densified ceramic bodies can be prepared by either a pressureless sintering process or a hot press sintering process. The compositions of this invention can be formed into desired shapes and then sintered to form ceramic, shaped bodies with high densities. One advantage of the present invention is that the green bodies have relative high strengths and thus can be easily handled and, if desired, machined before sintering. The preceramic polysilazanes useful in this invention must yield ceramic chars which contains free or excess carbon in addition to carbon in the form of silicon carbide upon pyrolysis to elevated temperatures.

公开(公告)号：DE3882446D1

公开(公告)日：1993-08-26

申请号：DE3882446

申请日：1988-06-08

Applicant: DOW CORNING

Inventor： BURNS GARY THOMAS

IPC: C04B35/56 ,  C04B35/571 ,  C04B35/589 ,  C08G77/48 ,  C08G77/60 ,  C04B35/00

公开(公告)号：DE3876304D1

公开(公告)日：1993-01-14

申请号：DE3876304

申请日：1988-06-08

Applicant: DOW CORNING

Inventor： BURNS GARY THOMAS

IPC: C01B21/068 ,  C04B35/571 ,  C04B35/589 ,  C08G77/48 ,  C08G77/62 ,  C04B35/56 ,  C04B35/58

Abstract: The reaction of 1,1-dichlorosilacyclobutanes with nitrogen-containing difunctional nucleophiles gives polysilacyclobutasilazanes which can be crosslinked and also converted to ceramic materials.

公开(公告)号：GB2233980B

公开(公告)日：1992-05-06

申请号：GB8820426

申请日：1988-08-26

Applicant: DOW CORNING COPORATION

Inventor： BURNS GARY THOMAS

IPC: C08G77/60

公开(公告)号：DE3777700D1

公开(公告)日：1992-04-30

申请号：DE3777700

申请日：1987-06-24

Applicant: DOW CORNING

Inventor： BANEY RONALD HOWARD ,  BURNS GARY THOMAS

IPC: C08K5/01 ,  C04B35/571 ,  C04B35/622 ,  C08K5/5425 ,  C08L83/02 ,  C08L83/04 ,  C08L83/05 ,  C08L83/07 ,  C08L83/16 ,  D01F9/10 ,  C04B35/56 ,  C08G77/60

Abstract: A method is disclosed for the preparation of ceramic materials with reduced oxygen levels from polycarbosilanes by the pyrolysis of a mixture of a polycarbosilane, a hydrosilylation catalyst, and an unsaturated compound selected from the group consisting of reactive diolefins, reactive alkynes, polyolefins, vinylsilanes, and unsaturated siloxanes where the mixture is rendered infusible prior to pyrolysis by heating to relatively low temperatures in an inert atmosphere. This invention is especially well suited for the production of ceramic fibers from polycarbosilanes.

公开(公告)号：GB2234255A

公开(公告)日：1991-01-30

申请号：GB8913184

申请日：1989-06-08

Applicant: DOW CORNING COPORATION

Inventor： BURNS GARY THOMAS

IPC: C04B35/571 ,  C08G77/48 ,  C08G77/60

Abstract: A process for the preparation of a methylpolysilane having a controlled carbon content is provided which includes the steps of heating together to form a reaction mixture at least one alkoxy-functional disilane selected from the group consisting of disilanes having two, three, and four alkoxy groups bonded to the silicon atoms, and mixtures thereof, with either an alkoxy-functional silane having at least one unsaturated substituent or an unsaturated hydrocarbon compound in an amount effective to increase the carbon content of the resulting polymer. The reaction is carried out in the presence of a catalyst which is a source of alkoxide ions. The methylpolysilane polymers produced may be pyrolyzed to form ceramic compositions having increased carbon contents. The ceramics may find use as films, fibers, and coatings, as well as the many other uses to which silicon carbide ceramics have heretofore been put.

公开(公告)号：GB2233980A

公开(公告)日：1991-01-23

申请号：GB8820426

申请日：1988-08-26

Applicant: DOW CORNING COPORATION

Inventor： BURNS GARY THOMAS

IPC: C08G77/60

公开(公告)号：GB2223231A

公开(公告)日：1990-04-04

申请号：GB8916143

申请日：1989-07-14

Applicant: DOW CORNING

Inventor： BURNS GARY THOMAS

IPC: C04B35/571 ,  C08G77/48 ,  C08G77/60

Abstract: A process for the preparation of a methylpolysilane having a controlled carbon content is provided which includes the steps of heating together to form a reaction mixture at leasdt one alkoxy-functional disilane selected from the group consisting of disilanes having two, three, and four alkoxy groups bonded to the silicon atoms, and mixtures thereof, with either an alkoxy-functional silane having at least one unsaturated substituent or an unsaturated hydrocarbon compound in an amount effective to increase the carbon content of the resulting polymer. The reaction is carried out in the presence of a catalyst which is a source of alkoxide ions. The methylpolysilane polymers produced may be pyrolyzed to form ceramic compositions having increased carbon contents. The ceramics may find use as films, fibers, and coatings, as well as the many other uses to which silicon carbide ceramics have heretofore been put.