新型碳纤维用原丝——高强高模Lyocell纤维纺丝工艺研究

采用天然高相对分子质量纤维素脱脂棉为原料 ,制备了高强高模纤维素纤维 ( L yocell纤维 ) ,并用此作为碳纤维原丝 ,成功制得了强度优于粘胶基碳纤维的 L yocell基碳纤维。考察了高相对分子质量纤维素的溶解特点 ,纺丝工艺对 L yocell纤维聚集态及性能的影响 ,比较了 L yocell纤维和粘胶原丝的表面及截面形态。实验表明 :高相对分子质量纤维素溶解的静溶胀时间和温度对其溶解有明显的影响 ;纺丝过程中 ,大的气隙长度对提高纤维的性能有利 ;随着凝固浴中 N -甲基吗啉 N -氧化物( NMMO )的浓度增加 ,纤维的强度和模量增加 ,当其在凝固浴中的质量分数达到 10 %时 ,强度模量最大 ,浓度继续增加 ,纤维的力学性能开始下降 ;拉伸比增加 ,L yocell纤维的强度模量增加 ,当拉伸比大于 3.0时 ,纤维的性能略有下降

Study on the process of high strength high modulus Lyocell fiber--a novel precursor for carbon fiber

High strength and high modulus Lyocell fibers have been produced by using high molecular weight (HMW) cellulose, degrease cotton, as raw material. The dissolving peculiarities of HMW cellulose in NMMO/H 2O solution and the effect of spinning process on the crystal structure and properties of Lyocell fiber were investigated. The surface and cross-section morphologies of Lyocell fiber and rayon precursor for carbon fiber were compared. The carbon fibers with high strength and modulus Lyocell fibers as the precursor could be produced with better mechanical properties as compared with those from rayon fibers. It was found that the swelling time and temperature of cellulose had profound influence on the dissolution of HMW cellulose; The properties of Lyocell fiber could be improved by increasing gap length during spinning; the tenacity and initial modulus of Lyocell fiber increased with increasing NMMO concentration in coagulation bath and draw ratio; however, in this system, the fiber's mechanical properties slightly decreased when NMMO concentration and draw ratio exceeded 10% and 3 0, respectively.