| 摘要 |
Novel polysiloxane-silazane preceramic polymer compositions are prepared by the controlled hydrolysis polymerization of a trimer or tetramer of a monomer of the structure <IMAGE> wherein R1, R2, R3, and R4 are independently alkyl groups containing from 1 to 4 carbon atoms, Ra, Rb, Rc, and Rd are independently alkenyl or alkyl groups containing from 2 to 6 carbon atoms with the proviso that at least one of Ra, Rb, Rc, or Rd group is an alkenyl group. The polysiloxane-silazane polymers are cured by heat and optionally free radical initiators such as various peroxides. The cured preceramic polymers so formed can be u sed in the pyrolyzed or non-pyrolyzed state as adhesives, coatings, binders, fibers, matrix resins, and the like.
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