超声波处理对对位芳纶纤维侵蚀性能的影响

Erosion of para-aramid fiber caused by ultrasonic treatment

利用超声波对蒸馏水和自配海水中的国产对位芳纶和美国杜邦Kevlar49纤维分别进行不同时间段的处理,进行红外光谱和黏度检测并计算其处理前后的分子质量及聚合度。结果表明,2种纤维均由聚对苯二甲酰对苯二胺构成,但国产对位芳纶纤维分子质量和聚合度均小于Kevlar49纤维。通过扫描电镜观察和力学性能测试发现,经过超声波处理后的纤维表面出现裂缝并存在微细原纤维,呈分丝帚化及细纤维化现象,强力弱环增加,纤维断裂强度与断裂伸长率均下降,并在24～48 h时发生的变化速率达到最大。同时利用分子运动理论对纤维的力学损失进行分析。

The home made para-aramid fibers and Kevlar49 fibers made by DuPont were subjected to ultrasonic treatment in distilled water and seawater, respectively, varying the treatment durations. The infrared spectrum and viscosity testing were conducted and molecular weight and degree of polymerization of the fibers before and after treatment were calculated. The results showed that both the two kinds of fibers consist of polyphenylene terephthalamide, however, the molecular weight and degree of polymerization of home made para-aramid fibers are lower than those of Kevlar49 fibers. SEM observation and mechanical strength testing found that cracks and fibrillation appeared on the surface of the fibers after ultrasonic treatment, their breaking strength and elongation at break lowered, and the change rate reached the peak values within 24 to 48 hours. Molecular kinetic theory was used to study the loss of fibers＇ mechanical strength.