研究不同应力和温度条件下聚丙烯材料的蠕变行为。试验结果表明,聚丙烯材料的蠕变行为是非线性的。同一应力水平下不同温度的蠕变柔量曲线满足时间-温度等效原理.通过水平移位可以得到光精的蠕变柔量主曲线,移位因子与温度变化成线性关系.但不同应力水平下的时间-温度移位因子是不同的.从蠕变乘量主曲线和温度移位因子可知,应力为16MPa时14—26℃下的短期(1500s)试验数据可以用于预估14℃时长达3d的蠕变性能.
The creep behavior of polypropylene (PP) was investigated at varius stresses and temperatures. The test duration was only 1500 seconds. The test measurements show that the creep behavior of PP is nonlinear in nature for the stress interval investigated in this paper, the creep compliance curves at a given stress but different temperatures can be shifted along the log time axis to construct a smooth master curve up to 3 days at a reference temperature of 14 ℃, indicating that the time - temperature superposition principle works successfully. Moreover the time - temperature shift factors are linearly proportional to the temperature changes, and depend on the stress levels.