基于乙二醇链段构象变化的涤纶工业丝聚集态结构研究

Research on aggregate structure of polyester industrial filament based on conformational changes of ethylene glycol segments

在150℃烘箱中对3种不同纺丝工艺即常规工艺(A)、提高喷丝头拉伸倍数(B)、提高喷丝头拉伸倍数并降低第二级拉伸倍数(C)制备的涤纶工业丝试样F-A、F-B、F-C进行30~120 d热处理,研究纺丝工艺及热处理时间对涤纶工业丝乙二醇链段构象的影响,以此考察涤纶工业丝的聚集态结构变化。结果表明:提高喷丝头拉伸倍数促使纤维中乙二醇链段的旁式构象向反式构象转变,降低第二级拉伸倍数不足以破坏纤维的原有结构;喷丝头拉伸倍数从109.62提高到120.00,试样的乙二醇链段反式构象相对含量(X_(t))从23.37%增加至29.00%,结晶度(X_(c))从43.04%降至42.57%;第二级拉伸倍数从3.389降至3.200,试样的X_(t)从29.00%增加至41.73%,X_(c)从42.57%提高至45.44%;对于F-A与F-C试样,随着热处理时间的延长,试样的X_(t)及X_(c)均先增加后下降,均在热处理90 d时出现最大值;而对于F-B试样,随着热处理时间的延长,试样的X_(t)及X_(c)均逐渐增大,在热处理120 d时分别达到64.90%与63.36%。

Three different spinning processes,namely traditional process(A),raising spinneret draw ratio(B)and reducing the second draw ratio based on the elevation of spinneret draw ratio(C),were applied to prepare polyester industrial yarn samples(F-A,F-B,F-C)which were exposed to 30-120 days of heat treatment in a 150℃oven.The effects of spinning process and heat treatment time on the ethylene glycol chain conformation of polyester industrial yarn were studied to investigate the changes in the aggregate structure of polyester industrial yarn.The results showed that increasing the spinneret draw ratio promoted the transformation of the side conformation of ethylene glycol chain segment in the fiber to the trans conformation,and reducing the second draw ratio was not enough to damage the original structure of the fiber;the relative content(X_(t))of the trans conformation of ethylene glycol chain segment in the sample increased from 23.37%to 29.00%,and the crystallinity(X_(c))decreased from 43.04%to 42.57%when the spinneret draw ratio increased from 109.62 to 120.00;the X_(t)of the sample increased from 29.00%to 41.73%and the X_(c)increased from 42.57%to 45.44%when the second draw ratio decreased from 3.389 to 3.200;for samples F-A and F-C,as the heat treatment time was prolonged,the X_(t)and X_(c)of the samples both first increased and then decreased,reaching their maximum values after 90 days of heat treatment;and for sample F-B,as the heat treatment time was prolonged,the X_(t)and X_(c)of the sample gradually increased,reaching 64.90%and 63.36%respectively after 120 days of heat treatment.