物理老化对非晶态聚醚砜共聚物力学性能和形态结构的影响

采用示差扫描量热法（DSC）、 应力 应变测量、 荧光光谱和透射电镜等方法研究了物理老化对非晶态聚醚砜共聚物膜的拉伸屈服行为及微观结构的影响. 研究结果表明， 聚醚砜共聚物经物理老化后， DSC升温曲线上出现吸热峰，T_g升高， 初始模量和屈服应力增加， 断裂伸长率下降. 物理老化后的聚醚砜共聚物在拉伸过程中出现应力屈服峰， 实质上是逐步打开凝聚缠结的过程. 荧光光谱的研究证明， 非晶态聚醚砜共聚物由于主链苯环密度较高， 苯环受激处于激发态时易与周围激态苯环相互作用形成激基缔合物， 缔合物发射峰的强度随老化时间增加而增强. 电镜对形态结构的分析进一步表明， 聚醚砜共聚物经物理老化后其聚集态形成了某种局部有序结构.

Effects of Physical Aging on Mechanical Properties and Morphological Structure of Amorphous PES Copolymer

Effects of physical aging on the tensile properties,stress yielding mechanism and submicroscopic structure of amorphous PES copolymer film were studied by DSC,stress-strain curve and fluorescence spectrum measurements.It was shown that an endothermic peak appeared on the DSC curve and the T_g increased, its initial modulus and yield stress increased while the elongation decreased.The viewpoint of cohensional entanglement (CE) was employed to interpret the experimental results,which indicated that the stress yielding of aged PES copolymer was the destruction of the CE formed during aging.The study of fluorescencespectrum proved that the excited phenylene-rings of amorphous PES copolymer with high density phenylene-rings in its main chain could form an excimer with the surrounding unexcited phenylene-rings,and the emission peak intensity of excimer was strengthened with the increase of aging time.The result of electron-microscopy investigation indicates that PES copolymer has formed a local order structure during the physical aging.