【摘要】 将聚丙烯(PP)试样经过室内温差老化、紫外光340 nm和313 nm老化,并对老化前后试样进行力学性能测试、毛细管流变、扫描电镜等分析判断不同老化方法对PP试样老化程度的影响。结果表明,温差20℃时PP试样断裂伸长率保持率为58.7%,温差为100℃时的断裂伸长率保持率降为6.7%;紫外光340 nm老化3 d和20 d的断裂伸长保持率为48.8%和15.3%;紫外光313 nm老化3 d和20 d的断裂伸长保持率为44.6%和3.1%。毛细管流变10min时紫外光340 nm老化3 d和20 d的PP试样与未老化PP试样对比,扭矩由0.188 N·m降为0.168 N·m和0.112N·m;紫外光313 nm则降为0.164 N·m和0.084 N·m。基于此,不同老化方法对PP老化程度不同,其中紫外光313 nm由于其更高的能量使得PP试样的老化程度最大。更多还原

【Abstract】 Polypropylene was aged respectively under different temperatures in doors,or by ultraviolet irradiation of 340 nm and 313 nm. The effects of different aging methods on the aging degree of PP samples were studied by means of mechanical properties,capillary rheology and scanning electron microscopy. The results show that the retention of elongation at break was 58. 7% at 20 ℃ and 6. 7% at 100 ℃,respectively.The elongation at break under ultraviolet irradiation of 340 nm for 3 and 20 d was 48. 8% and 15. 3%,respectively,which was 44. 6% and 3. 1% under ultraviolet irradiation of 313 nm. Compared with the PP samples before aging,when 10 min in capillary rheological experiment,the torque of PP samples aged under ultraviolet irradiation of 340 nm decreased from 0. 188 N·m to 0. 168 N·m for 3 d and to 0. 112 N·m for20 d,while under ultraviolet irradiation of 313 nm,the torque decreased to 0. 164 N·m and 0. 084 N·m,respectively. Based on this,different aging methods make different aging degrees for PP and the ultraviolet irradiation of 313 nm makes more serious aging for PP samples because of higher energy.更多还原