中文摘要：

采用一步三阶段式控制法制备了一系列结构及环化率不同的芳香族聚噁二唑纤维,并研究了紫外光老化前后纤维结构和力学性能的变化,初步探讨了其光老化机理。结果表明,光老化24h,纤维强度保持30%,特性黏度保留60%;X射线衍射谱图显示老化后纤维晶粒尺寸发生变化;红外图谱表明老化后1710cm^-1附近产生新的羰基吸收峰,可能生成羰基化合物;从扫描电镜观察到老化后试样表面变得粗糙,出现沟槽等现象。

英文摘要：

A series of poly（phenylene-1,3,4-oxadiazoles） （PODs） were synthesized by the three-step method of poly-condensation and spun to fiber via wet spinning procedure. Based on artificial accelerated aging test,the structures and mechanical properties of samples before and after ultraviolet （UV） irradiation were characterized and measured. The aging mechanism of POD fibers was discussed. Mechanical properties test results showed that after 24 hours UV irradiation,strength retention of fibers was about 30% and the retention of the intrinsic viscosities of the corresponding specimens was 60%. There were no obvious changes in X-ray diffraction pattern of samples before and after aging. The result of FT-IR indicated that new absorption peak which attributed to the carbonyl group was present. Scanning electron microscope showed that the sample surface became crude. All the characterization results indicate that UV -degradation of PODs leads to the decrease of the molecular weight and the formation of carbonyl compounds.