PP及PP/EPDM共混物室内外老化行为的研究

通过中国西部3个地区（新疆尉犁、西藏拉萨和四川成都）室外自然老化和室内加速老化（热氧、紫外老化）的对比，研究了聚丙烯及聚丙烯/三元乙丙橡胶（PP/EPDM）共混物室内外老化前后力学性能的变化和表面微观形态的变化，以及其室内外老化的对应关系。结果表明，室外老化初期PP的拉伸强度提高，老化中后期随着降解程度加剧拉伸强度下降；EPDM的加入提高了PP的耐老化性能，其中成都地区老化试样最为明显，24个月后拉伸强度保持率高达115 %；PP和PP/EPDM共混物室内热氧老化后拉伸强度变化不大，紫外老化后拉伸强度则呈现下降趋势；综合考虑热氧和紫外老化，通过时间等效关系可以更好地联系室内外老化，为预测材料在自然状态下的服役寿命奠定了基础。

Study on Indoor and Outdoor Aging Behavior of PP and PP/EPDM Blends

Outdoor and indoor accelerated aging (thermal-oxidation and ultraviolet aging) of polypropylene (PP) and polypropylene/ethylene-propylene-diene monomer (PP/EPDM) blends were studied to monitor the change in mechanical properties and surface microstructure. The outdoor aging was carried out in three western regions of China: Yuli Xingjiang, Lasa Tibet, and Chengdu Sichuan. During the outdoor aging, the tensile strength of increased at the initial stage and decreased in middle and late stages due to degradation. The addition of EPDM greatly enhanced the anti-aging properties of PP, and the retention of tensile strength was up to 115% after 24 months aging in Chengdu. The tensile strengths of both PP and PP/EPDM were little affected during thermal-oxidation aging, but gradually decreased during UV aging. The accelerated indoor and outdoor aging could be correlated by a time equivalence considering both thermal-oxidation and UV.