细旦尼龙6纤维加工过程中的晶型转化行为

通过引入富镧稀土化合物等添加剂，成功实现了细旦尼龙6纤维的熔融纺丝．考察了在纺丝卷绕成型以及牵伸过程中尼龙6纤维的晶型变化．借助XRD和FT－IR等研究手段，发现尼龙6在纺丝过程中可以生成亚稳态的B晶型晶体．这种β晶型经过沸水处理后很容易转化为α晶型，而γ晶型尼龙6经沸水处理后不发生相转变．因此可以通过沸水热处理的方法区分尼龙6的β和γ晶型．在纤维的卷绕过程中，当熔体拉伸倍数较高时，尼龙6可能产生β晶型；当熔体拉伸倍数较低时，则以γ晶型为主．在纤维的牵伸过程中，γ晶型经过β晶型中间态向α晶型相转变．上述结果对于指导改进细旦尼龙6纤维的加工工艺以及提高产品性能有指导意义．

Crystalline behaviors and phase transition during the manufacture of fine denier PA6 fibers

Recently we have successfully produced fine denier PA6 fibers by using additive containing Lanthanide compounds. Meanwhile, crystallization and phase transition of PA6 fibers during spinning and drawing processes were investigated. During the spinning process, β phase crystal could be obtained in as-spun PA6 fibers which were produced with relatively high melt draw ratio, while t, phase crystal predominated when the melt draw ratio was relatively low. β phase crystal, whose behaviors are similarly with γ phase by FT-IR and XRD characterization, could transformed to α form easily when PA6 fibers is immersed in boiling water. However, γ phase crystal of PA6 remains unchanged in boiling water. Thus, β and γ phase crystals of PA6 can be differentiated by the crystalline behaviors of PA6 fiber after treatment by using boiling water. Further experiments demonstrate that the β phase can also be produced during a drawing process where a phase transformation from γ to α occurs. That is to say, β phase may act as an intermediate state during the phase transformation.