High-temperature pyrolysis of ceramic fibers derived from polycarbosilane-polymethylhydrosiloxane polymer blends with porous structures
High-temperature pyrolysis of ceramic fibers derived from polycarbosilane-polymethylhydrosiloxane polymer blends with porous structures
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DOI：
10.1007/s10853-009-3905-x
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发表时间：
2010-01-01
影响因子：
4.5
通讯作者：
Yoshikawa, Masahito
中科院分区：
文献类型：
--
作者：
Kita, Ken'ichiro;Narisawa, Masaki;Yoshikawa, Masahito
采用混合苯溶液冷冻干燥法制备了聚碳硅烷(PCS)与高分子量聚羟甲基硅氧烷(PMHS-h)的聚合物共混物。分析了制备的聚合物共混物的熔体粘度、质量损失和气体析出。将HSah15(PMHS-h与PCS的质量分数为15%)共混物熔融纺丝成纤维，经热氧化固化后在1773K以下进行不同温度的热分解，通过拉伸测试、场发射扫描电子显微镜(FE-SEM)观察和X射线衍射仪(X射线衍射仪)分析对所得纤维进行了表征。在1273K下热解后，纯PCS纤维的横截面上没有气孔，而HSah15纤维的横截面上有大量的气孔。在1773K热解后，纯PCS纤维的外表面形成了粗大的β-碳化硅晶体，而HSah15纤维的外表面没有形成明显的β-碳化硅晶体。
The polymer blends of PCS (polycarbosilane) and PMHS-h (polymethylohydrosiloxane with high molecular weight) were prepared by freeze-drying process of mixed benzene solution. Melt viscosity, mass loss, and gas evolution from prepared polymer blends were analyzed. A polymer blend of HSah15 (15 mass% PMHS-h to PCS) was melt-spun to fiber form, curing by thermal oxidation and pyrolyzed at various temperatures up to 1773 K. The obtained fibers were investigated by tensile tests, FE-SEM (field emission scanning electron microscope) observation, and XRD (X-ray diffraction) analysis. After pyrolysis at 1273 K, there were no pores in the cross section of the fiber derived from pure PCS; however, there were amounts of pores in the cross sections of the fiber derived from HSah15. After pyrolysis at 1773 K, the coarse beta-SiC (silicon carbide) crystals were formed on the outside surface of the fiber derived from pure PCS; however, no remarkable beta-SiC crystal were formed on the outside surface of the fiber derived from HSah15.