【摘要】 以聚对苯二甲酰对苯二胺(PPTA)为原料，以稀硫酸溶液为凝固浴，采用干喷湿纺制备对位芳纶，重点研究了凝固浴浓度、温度对对位芳纶结晶度、晶区取向度、微观形貌及力学性能的影响。结果表明：凝固浴硫酸质量分数为3%时，对位芳纶的结晶度、晶区取向度均最高，分别达57.0%、88.6%;凝固浴温度相对较低时，对位芳纶的晶区取向度均较高且差异不大，凝固浴温度为15℃时对位芳纶的结晶度最高，达58.5%;凝固浴浓度过低时对位芳纶皮-芯差异显著，凝固浴浓度过高时纤维间易发生黏连；凝固浴温度过低时对位芳纶结构疏松，凝固浴温度过高时纤维易产生微孔缺陷；凝固浴硫酸质量分数为3%、凝固浴温度为10℃时，对位芳纶成形好，结构均匀致密，且具有较好的力学性能，其断裂强度为26.2 cN/dtex,弹性模量为476.8 cN/dtex,断裂伸长率为4.7%。更多还原

【Abstract】 P-aramid fibers were prepared from poly(p-phenylene terephthalamide)(PPTA) with dilute sulfuric acid solution as coagulation bath by dry-jet wet spinning. The effects of coagulation bath concentration and temperature on the crystallinity, crystalline orientation, microstructure, and mechanical properties of p-aramid fibers were systematically investigated. The results showed that when the coagulation bath concentration was 3% by mass fraction, the crystallinity and crystal orientation of p-aramid fibers reached their highest values at 57.0% and 88.6%, respectively; the crystalline orientation of p-aramid fibers remained high with minimal variation at relatively low coagulation bath temperatures, while the crystallinity peaked at 58.5% when the coagulation bath temperature was 15 ℃; excessively low coagulation bath concentrations resulted in significant skin-core differences in fibers, whereas excessively high concentrations led to fiber-fiber adhesion; excessively low coagulation bath temperatures resulted in loose structures, whereas excessively high temperatures induced microporous defects; when the sulfuric acid mass fraction in the coagulation bath was 3% and the coagulation bath temperature was 10 ℃, the p-aramid fibers exhibited good formability, a uniform and compact structure, and favorable mechanical properties, with a tensile strength of 26.2 cN/dtex, an elastic modulus of 476.8 cN/dtex, and an elongation at break of 4.7%.更多还原