十氢萘的异构性对UHMWPE凝胶纺丝的影响

Effects of decalin solvent isomerism on UHMWPE gel spinning

超高分子量聚乙烯(UHMWPE)在十氢萘溶剂中的溶胀和溶解状态对UHMWPE冻胶纺丝工艺及纤维性能产生重要的影响。十氢萘具有顺式和反式两种异构体,不同的异构体及其复配对UHMWPE有不同作用。本文基于冻胶丝制备过程中的预溶胀和挤出塑化,围绕十氢萘的顺/反式异构体结构对UHMWPE凝胶纺丝性能的影响进行研究。结果表明:干法纺丝合适的UHMWPE质量分数为6%;UHMWPE较佳的预溶胀条件为95~100℃浸渍3 h;与顺式十氢萘相比,反式十氢萘由于具有立体结构对称和偶极矩较小等特点更易促使UHMWPE溶胀和解缠,从而有利于UHMWPE分子链在多级高倍拉伸过程中形成伸直链结晶;预溶胀体在大于130℃下均能完全塑化,UHMWPE反式十氢萘熔体的扭矩相对更低,有利于改善纺丝工艺,提升纤维性能。

The swelling and dissolution conditions of ultra-high molecular weight polyethylene(UHMWPE)in decalin solvent have an important influence on the jelly spinning process and fiber properties.Decalin has two isomers of cis-and trans-,and different isomers and their complexes have different effects on UHMWPE.In this paper,based on the pre-swelling and extrusion plasticization in the preparation process of jelly fiber,the UHMWPE gel spinning was studied around the cis-/trans-isomer structure of decalin.Results showed that the suitable mass concentration for UHMWPE dry spinning was 6%.The best pre-swelling condition for UHMWPE was 95100℃and immersed for 3 h.Compared with cis-decalin,the trans-decalin was easier to cause the swelling and untangling of UHMWPE due to its three-dimensional structure symmetry and smaller dipole moment,which was conducive to the formation of straight chain crystals in the UHMWPE molecular chain during the multi-stage super stretching process.When the temperature was higer than 130℃,the pre-swelling body could be completely plasticized.But the UHMWPE/trans-decalin fusant had relatively lower torque,which would improve the spinning process and enhance the fiber performances.