摘要
在25℃下研究了应力、退火处理、紫外辐照等外界因素对聚丙烯(PP)蠕变行为的影响。发现PP在蠕变过程中存在临界失效现象,而且外界因素只对临界失效现象出现的时间产生影响,而不会影响临界失效应变值(εcr)的大小。PP在蠕变过程中内部微观结构发生着复杂的变化:在25 MPa下,蠕变初期随着形变的增加,分子链取向排列诱导二次结晶,导致材料的取向度和结晶度增加;自由体积尺寸增大,当自由体积尺寸达到最大值时,分子链的活动能力最强,出现临界失效现象。
The effects of stresses,heat treatment and UV light on the creep behavior of polypropylene at 25 ℃ were studied.Critical failure behavior was observed in all creep tests of PP.The stresses,heat treatment and UV light did not affect the value of the critical failure strain but the time when critical failure behavior occurring.As to the changes of microstructure in polypropylene,they were more complex.With the increase of the deformation during creep,the orientation and rearrangement of molecular chains made the degree of orientation and crystallinity increase in the beginning at 25 MPa.The molecular chain had a strongest activity when the free volume size reached the maximum,where the critical failure behavior was exhibited.
出处
《塑料工业》
CAS
CSCD
北大核心
2014年第8期85-88,共4页
China Plastics Industry
基金
高等学校博士学科点专项科研基金(20120181130013)
关键词
聚丙烯
蠕变
微观结构
临界失效
Polypropylene
Creep
Microstructure
Critical Failure
