汽车用材料——PA66及其玻璃纤维复合材料在不同介质中的老化行为研究

在三种介质（二次水，汽油，乙二醇，50℃温度）条件下对PA66及PA66／GF进行95天左右的人工模拟材料在汽车使用环境下的加速试验，对不同老化时间的PA66及PA66／GF试样进行了宏观力学测试及吸湿性测试，并进一步利用示差扫描量热法（DSC），红外光谱及扫描电镜等手段分析老化前后试样的微观结构及组织差异。结合老化前后试样的力学性能变化，揭示了PA66及复合材料的老化规律和机理。实验表明，PA66及PA66／GF在三种介质中拉伸强度呈现下降趋势。其主要机理是介质溶液对试样渗入的结果影响，降低了分子间的相互作用力（范德华力）从而使材料机械性能下降；同时未发现化学作用对材料的力学性能有明显的变化。

Study on Aging Property of Automotive Materials-PA66 and Glass Fiber Composite Materials in Different Solution

The accelerated aging experiments of the conditions of automobile for PA66 and PA66/GF specimens were conducted for 95d at 50℃ in three different solutions(water,petrol and ethanediol).The macro-mecha-nical characteristics and hygroscopicity of PA66 and PA66/GF were tested at different time during the experiments,and the structure and composition difference of the samples before and after aging were analyzed by means of DSC,FTIR and SEM.Combined with the mechanical data,the aging mechanisms of PA66 and PA66/GF in different solutions were clarified qualitatively.The results showed the tensile strength tended to degrade after the aging of the three solutions.The aging mechanism was mainly the impact of the permeation of the solutions molecule.Owing to this reason,the intermolecular force of PA66 and PA66/GF decreased,which made the mechanical properties of PA66 and PA66/GF degraded;the chemical action on PA66 and PA66/GF in different solutions did not change the mechanical properties.