PVA作纺丝助剂制备莫来石-氧化铝长纤维

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。

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

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 Al/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 at1 200 ℃ for 1 h，and their main phase was identified as γ-Al₂O₃ and mullite.