| 摘要 |
The invention provides branched copolymers as precursors for preparing silicon carbide (SiC) ceramics represented by the general formulae: [Si(~)RC(~)H]xn[SiR1R2CH2]yn,Formula Type-I wherein n is the degree of polymerization, 0.1@x<0.8, 0.2@y<0.9 and x+y=1; and R=methyl or H, R1 and R2 are randomly composed of hydrogen (H), allyl, methyl (Me), phenyl (Ph), propargyl or vinyl. Another branched copolymer is represented by the general formula: [Si(~)RC(~)H]xn[SiR1R2CH2]yn[SiR3R4CH2]znFormula Type-II wherein n is the degree of polymerization, 0.1@x<0.8, 0@y<0.8, 0.2@z<0.8 and x+y+z=1; and R=methyl or H, R1 and R2 are randomly composed of hydrogen (H), methyl (Me) and phenyl; R3 and R4 are randomly composed of H, allyl, methyl, phenyl (Ph), propargyl, and vinyl. The invention also provides methods for the preparation of such branched copolymers. |
