均聚聚丙烯在干热环境中耐候性能及结构表征

Weathering Performance and Structure Characterization of Homopolymer PP in Dry Environment

以吐鲁番户外暴晒场为聚丙烯(PP)及耐候性PP的自然老化试验点,连续暴晒12个月。在室外暴晒过程中,研究了材料的断裂伸长率和冲击强度、表面微观形态和元素组成、相对分子质量及其分布的变化,分析了防老化助剂对聚丙烯耐老化性能的影响。结果表明,试样PP-0暴晒90 d后断裂伸长率和冲击强度保持率分别降至6.4%和5.6%,氧元素增加了23.21%,重均相对分子质量从24.2万降至8.07万,表面出现大量宽度为3.05μm的裂纹。而耐候改性的PP-3试样中防老化助剂能够起到协同后补作用,抑制热氧光对PP的降解老化速度,从而提高聚丙烯的使用寿命。

Turpan was chosen as outdoor exposure field for natural ageing test of PP and weather-resistance PP, continuous exposure for 12 months. The elongation at break and impact strength, surface microscopic morphology and elemental composition, molecular weight and molecular weight distribution of samples were studied in process of outdoor exposure. The results show that elongation at break and impact strength retention rate of sample PP-0 after 90 d exposure fall to 6.4% and 5.6%, respectively, an increase of 23.21% for oxygen content, the average molecular weight of sample is reduced from 242000 to 80700, a large number of surface cracks with the width of 3.05μm. While the anti-aging aids of weathering modified PP-3 samples can play a synergistic effect, inhibiting degradation rate of PP, thereby increasing life of polypropylene.