PVA作纺丝助剂制备莫来石-氧化铝长纤维

Preparation of long mullite-alumina fibers with PVA as spinning additive

用氯化铝和铝粉为原料制备了铝溶胶,再向铝溶胶加入硅溶胶、封端剂和聚乙烯醇(PVA)纺丝助剂,制得莫来石-氧化铝溶胶,研究了纺丝助剂加入量对溶胶纺丝性能的影响。研究发现,溶胶在浓缩时,胶粒间发生缩合反应,形成线性或非线性的分子链,生成可纺的黏性溶胶;在溶胶中加入纺丝助剂,铝/硅离子或胶粒与纺丝助剂的活性基团发生缩聚反应,生成有机-无机的杂化分子链,提高了溶胶的纺丝性能;在加入封端剂的同时,加入质量分数为1%的PVA,凝胶纤维的最大长度可达100 cm。凝胶纤维在1 200℃下烧结1 h后,得到的陶瓷纤维的物相为γ-Al2O3和莫来石相,纤维表面光滑、直径均匀。

Abstract： Alumina sol was synthesized from dissolution of aluminum powder in aluminum chloride hexahydrate solution.The mullite-alumina sol was obtained by mixing alumina sol ,silica sol blocking agent, and spinning additive polyvinyl alcohol （PVA）.Effect of addition content of spinning additive on sol spin-abilty was studied.Results showed that viscous sol with spin-ability was obtained and linear or nonlinear molecular chains were produced by reacting between colloidal particles in sol when the sol was concentrated ; organic-inorganic hybrid molecular chains were generated and spinning performance of sol was improved by adding spinning assistant when the active groups of A1/Si ions or particles reacted with spinning assistant in sol;the maximum length of the gel fibers achieved about 100 cm when the blocking agent and 1% （mass fraction） spinning additive were added at the same time.The fibers with a smooth surface and uniform diameter were obtained by sintering at 1 200℃ for 1 h, and their main phase was identified as γ-Al2O3 and mullite.