将聚碳硅烷(PCS)纤维在1-己炔气氛中进行化学气相交联不熔化处理,与空气不熔化相比,能大大降低纤维的氧含量.PCS纤维在1-己炔气氛中反应,其组成和结构都发生了变化.结果表明,在1-己炔气氛中,PCS分子的Si-H键的反应程度和纤维的凝胶含量随温度的升高而逐渐增加.反应机制为1-己炔受热引发PCS分子中的Si-H和Si-CH3键断裂生成Si自由基和Si-CH2自由基,促进PCS分子间形成Si-CH2-Si交联结构,最终实现不熔化.反应中有少量己基引入到PCS分子结构中.制得的SiC纤维拉伸强度达到2.79 GPa,氧含量降低到5 wt%～6 wt%,并且纤维的耐高温性能明显优于Nicalon纤维.在Ar气中处理至1300℃,纤维强度保留率约为80%,处理至1400℃,纤维的强度保留率为60%,并且在1300～1600 ℃的处理过程中,纤维中β-SiC微晶的晶粒尺寸变化只有2.18 nm.
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