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采用TA-Q800动态热机械分析仪(DMA)研究了聚乙烯基对苯二甲酸二(对丁氧基苯)酯(PBPCS)纤维的形变回复性能,发现PBPCS纤维具有非常好的形状记忆效应,在145℃及以上温度,形状回复速率最好,9min左右可以从400%的伸长回复到原来的尺寸,于145℃,重复实验5次,结果说明形变回复重复性好.二维X衍射(2DX-Ray)研究显示形变前后PBPCS柱状分子直径d由2.54nm变为2.42nm,表明拉伸后PBPCS螺旋状的大分子主链处于更为伸直的构象,因此分子主链产生一定的内应力,即形变回复应力.由此可见,PBPCS相对柔性的聚乙烯主链使纤维具有良好的形变回复性能,而侧基的甲壳效应使得纤维能够保持初始尺寸,即PBPCS所具有的类似弹簧的特殊螺旋状分子结构是其纤维具有形状记忆效应的内在原因.
The deformation recovery of poly (ethylene terephthalate) (PBPCS) fiber was studied by TA-Q800 dynamic mechanical analyzer (DMA). It was found that PBPCS fiber has a very good shape memory effect, At the temperature of 145 ℃ and above, the shape recovery rate is the best, and it can be recovered from 400% elongation to its original size in about 9min. The experiment is repeated at 145 ℃ for 5 times, which shows that the deformation recovery is good. 2DX-Ray) showed that the diameter d of PBPCS columnar molecules changed from 2.54 nm to 2.42 nm before and after deformation, indicating that the PBPCS helical macromolecule backbone is in a more straight conformation after stretching, so that the molecular backbone generates some internal stress , That is, the strain recovery stress. It can be seen that the relatively flexible polyethylene backbone of PBPCS gives the fiber a good strain recovery performance, while the pendant effect of the pendant group enables the fiber to maintain its original size, ie, a special spring-like spiral The molecular structure is the inherent reason that the fiber has shape memory effect.