聚碳硅烷强化辐射交联的研究

STUDY ON THE ENHANCED IRRADIATION CROSSLINKING OF POLYCARBOSILANE

合成了不同乙烯基含量的聚碳硅烷 ,研究了其 He气氛条件下的电子束辐射交联不熔化处理 ,分析了含乙烯基聚碳硅烷纤维在辐照过程中的结构变化。结果表明 ,乙烯基起到强化聚碳硅烷辐射交联的作用 。

To synthesize polycarbosilane(PCS) derived low oxygen SiC fibers(Hi Nicalon), a 10~15 MGy irradiation is required for PCS′s curing. It is necessary to lower the irradiation doses in view of efficiency and costs. In the paper, various vinyl containing PCS(Vi PCS) were prepared by a thermal co polymerization of PCS and ammonolysis product of ViMeSiCl 2. They were crosslinked with electron beam(EB) irradiation in helium atmosphere. Effects of EB irradiation and vinyl content on the structure properties of Vi PCS precursors were analyzed. It shows that the more vinyl contained in Vi PCS increases rapidly its melting point and decreases its gel dose. The Vi PCS with a vinyl content of 2.33 mass percent is cured at just 5 MGy, much lower than that of the pure PCS. Vinyl can enhance PCS′s irradiation crosslinking by stimulating its Si-H bonds′ rearrangements through a free radical reaction. Little oxygen is contained in the irradiated Vi PCS precursors.