ABSTRACT Cross-linking is favourable for increasing ceramic yield and avoiding melting or deformation of SiC ceramic precursor polycarbosilane (PCS) during pyrolysis. In order to achieve hollow SiC fibre, PCS fibre with a limited cross-linking depth was prepared by chlorinating the Si–H group in the outer layer of PCS fibre followed by hydrolysis and condensation of the formed Si–Cl group. The chlorination was implemented through a gas–solid reaction between Cl2 and PCS fibre. Based on the results of energy-dispersive spectrometer and attenuated total reflectance–Fourier transform infrared spectroscopy, the diffusion-controlled chlorination reaction was confirmed. During hydrolysis, the catalysis of ammonia gas was necessary. According to the results of dissolution and degradation experiments, cross-linked PCS outer layer formed after chlorination, hydrolysis and condensation, and the outer layer had higher ceramic yield than the core part. After pyrolysis, SiC fibre with hollow morphology was formed. By adjusting the chlorination degree, the morphology of resulting hollow SiC fibre could be modified.

中文翻译：

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扩散控制交联法制备聚碳硅烷纤维中空碳化硅陶瓷纤维

摘要 交联有利于提高陶瓷产量，避免 SiC 陶瓷前驱体聚碳硅烷 (PCS) 在热解过程中熔化或变形。为了获得中空 SiC 纤维，通过氯化 PCS 纤维外层的 Si-H 基团，然后水解和缩合形成的 Si-Cl 基团来制备具有有限交联深度的 PCS 纤维。氯化是通过 Cl2 和 PCS 纤维之间的气固反应实现的。基于能量色散光谱仪和衰减全反射-傅立叶变换红外光谱的结果，证实了扩散控制的氯化反应。在水解过程中，需要氨气的催化作用。根据溶解降解实验结果，氯化后形成交联的PCS外层，水解和缩合，外层的陶瓷产率高于核心部分。热解后形成具有中空形态的碳化硅纤维。通过调节氯化度，可以改变所得中空碳化硅纤维的形貌。