UV-234对PC／ABS合金耐热氧老化性能的影响

Influence of UV-234 on the Thermal Oxidative Aging Resistance of PC / ABS Alloys

采用熔融共混工艺方法,UV-234为耐热氧老化改性助剂,选用合适的聚碳酸酯(PC)和丙烯腈-丁二烯-苯乙烯共聚物(ABS)为合金基材,制备了耐老化PC/ABS合金。通过机械性能测试、色差测试及扫描电镜(SEM),对所得合金老化前后的性能、外观及微观结构进行了表征,并探讨了UV-234对合金耐热氧老化性能影响的机理。结果表明,在热老化初期,UV-234起到了类似酚类抗氧剂的作用,合金老化过程中自由基的生成得到了更好地抑制,从而有效阻止了合金的老化断链及极性发色基团的生成,改善了合金的耐热氧老化性能;而在热氧老化后期,由于UV-234的分子结构变化,逐渐失去了对合金老化过程中自由基的抑制作用,合金热氧老化速度加快,其力学性能急剧下降,黄变程度增大。

An aging resistant polycarbonate （PC）/acrylonitrile-butadiene-styrene （ABS） alloy was prepared with PC and ABS as the matrix materials, UV-234 as the modifying agent by melt blending. The properties, appearance and microstructure of the alloy before and after ageing were characterized through mechanical properties test, color difference test and scanning electron microscope （SEM）. And the mechanism of UV-234 improving the aging resistance of the alloy was discussed. The results show that ： in the early stage of thermal oxidative aging, UV-234 plays a similar role of phenolic antioxidant, so the generation of free radicals is suppressed more effectively. And furthermore, the chain scission and the polar chromophore are also inhibited so that the thermal oxidative aging resistance of the alloy is improved. In the late stage of thermal oxidative aging, UV-234 loses the inhibition of free radicals due to its structural transformation, and the thermal oxidative aging speed and the degree of yellowing increase while the mechanical properties are of a sharp decline.