剪切均匀性对流动诱导等规聚丙烯结晶的影响

发布时间：2018-07-01 10:46

本文选题：均匀剪切 + 速率上升时间　；参考：《高分子学报》2017年09期

【摘要】：固定应变和最终应变速率,采用瞬时和缓慢2种电机加速方式对样品施加剪切,研究了流场加载模式对样品流变和结晶行为的影响.实验结果显示缓慢加速能够消除剪切过程中流场的非均匀性,使样品取向度增加,提高流场对聚合物熔体的作用效果.同时,流动诱导结晶对于加速时间有依赖性.对于速率为17.7 s-1的剪切,加速时间为1 s时,熔体流动均匀且流动诱导的晶体取向最强,短加速时间(0.5 s)和长加速时间(1.5 s)样品的流动诱导结晶效果都弱于加速时间为1 s的样品.但是,对于不同剪切速率,其对应的最优加速时间不同.对于流动诱导结晶来说,加速时间应当作为一个重要参数来考虑,其背后的真实物理含义还需要进一步研究来说明.
[Abstract]:The effect of flow field loading mode on the rheology and crystallization behavior of the sample was studied by using instantaneous and slow acceleration mode of motor to shear the samples at fixed strain and final strain rate. The experimental results show that slow acceleration can eliminate the inhomogeneity of the flow field in the shear process, increase the orientation of the sample, and improve the effect of the flow field on the polymer melt. At the same time, fluid-induced crystallization is dependent on acceleration time. For shear at a rate of 17.7 s ~ (-1), when the acceleration time is 1 s, the melt flow is uniform and the crystal orientation induced by flow is the strongest. Both short acceleration time (0.5 s) and long acceleration time (1.5 s) showed that the fluid-induced crystallization of the samples was weaker than that of the samples with acceleration time of 1 s. However, for different shear rates, the corresponding optimal acceleration time is different. For fluid-induced crystallization, acceleration time should be considered as an important parameter.
【作者单位】：国家同步辐射实验室中国科学技术大学;
【基金】：国家自然科学基金(基金号51325301,51227801)资助项目
【分类号】：O632.12

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