热氧老化时间对HDPE/Na_(2)SO_(4)复合材料性能的影响

Effect of thermal oxygen aging time on the properties of HDPE/Na_(2)SO_(4)composites

探究了120℃温度下不同热氧老化时间对高密度聚乙烯(HDPE)/硫酸钠(Na_(2)SO_(4))复合材料性能的影响,通过扫描电镜(SEM)、力学性能测试、热失重分析(TG)、差示热量热分析(DSC)、非等温结晶动力学模型(Jeziorny方程)以及热降解动力学模型(Kissinger方程、Flynn-Wall-Ozawa方程、Coats-Redfern方程)等表征方式分析了添加抗氧化剂1010前、后不同热氧老化时间对HDPE/Na_(2)SO_(4)复合材料力学性能、结晶性能、热稳定性能以及降解动力学、结晶动力学的综合影响。结果表明:随着热氧老化时间的增加,HDPE/Na_(2)SO_(4)复合材料的力学性能、结晶性能、热稳定性均下降(复合体系失效方式是HDPE/Na_(2)SO_(4)复合材料内部开裂所致),添加抗氧化剂1010后,同一老化时间下,HDPE/Na_(2)SO_(4)复合材料的热稳定性、力学性能以及结晶速率和结晶度得到提升;基体HDPE的晶体生长方式发生改变;HDPE/Na_(2)SO_(4)复合材料结晶机理呈单一的二维片晶生长;复合体系热降解机理在添加抗氧化剂后并未发生变化。

The effects of different thermal-oxidative aging times on the properties of high-density polyethylene(HDPE)/sodium sulfate(Na_(2)SO_(4))composites at 120℃were investigated.Scanning electron microscopy(SEM),mechanical property tests,thermal weight loss analysis(TG),differential calorimetric thermal analysis(DSC),non-isothermal crystallization kinetic model(Jeziorny equation),and thermal degradation kinetic model(Kissinger equation,Flynn-Wall-Ozawa equation and Coats-Redfern equation)were used to analyze the combined effects of different thermal and oxygen aging times on the mechanical properties,crystallization properties,thermal stability properties,degradation kinetics and crystallization kinetics of the polymer composites before and after the addition of antioxidant 1010.The results showed that the mechanical properties,crystallization properties and thermal stability of HDPE/Na_(2)SO_(4)composites decreased with the increase of thermal-oxidative aging time(the failure mode of the composite system was due to the internal cracking of HDPE/Na_(2)SO_(4)composites),and after the addition of antioxidant 1010,the thermal stability,mechanical properties and the crystallization rate and crystallinity of HDPE/Na_(2)SO_(4)composites were improved;The crystal growth of matrix HDPE was changed;The crystallization mechanism of HDPE/Na_(2)SO_(4)composites showed a single two-dimensional sheet crystal growth;The thermal degradation mechanism of the composite system did not change after the addition of antioxidant.