High ceramic yield synthesis of polycarbosilane

The present invention discloses a method for synthesizing a high ceramic yield polycarbosilane, the polycarbosilane molecular weight of 500-1500 with an allyl compound 100: (12 to 4) are mixed, dissolved in xylene, was placed reaction vessel was added an organolithium reagent, under a protective gas shielded heating reaction, controlling the maximum reaction temperature is 100 ~ 150 ℃, and incubated for 2 to 8 hours. after completion of the reaction, insolubles were filtered off, the solvent was evaporated, to give high ceramic yield polycarbosilane. The present invention has the easy control of the reaction conditions, simple method, the product has the characteristics of a self-crosslinking capability, and the Si-H with an allyl content of adjustable, can conveniently be prepared in liquid or solid high ceramic yield polycarbosilane.