以一种塑料水杯为研究对象,通过设定不同熔体温度、模具温度、注射时间及保压压力作变量,对不同条件下聚合物熔体剪切速率分布情况及其对结晶度的影响机制进行研究.结果表明,在充模流动方向上剪切速率随着距离浇口位置越远而逐渐减小,厚度方向上剪切速率呈现对称的"V"状分布,分别在中心层和距模具0.1 mm处达到最小和最大值;不同熔体温度与模具温度下熔体剪切速率分布规律相似,影响制品结晶性能的关键因素是二者的温度差;在成型过程中缩短注射时间或增加注射速率将有利于分子链发生结晶,而保压压力则对制品结晶度影响不大.%Taking a plastic water cup as the research object,by setting different melt temperature,mold temperature, injection time and packing pressure as variables,the influence of polymer melt shear rate distribution under different conditions on its crystallinity mechanism was researched. The results show that the shear rate along flow direction gradually decreases with the increase of distance from the gate. While along thickness direction,the shear rate shows a symmetrical "V" shape distribution and reaches the minimum at the core and maximum at 0.1 mm from the surface. The shear rate distribution of melt at different melt temperatures is similar to the distribution under different mold temperatures. The key factor affecting the crystallization performance of products is the temperature difference between them. During the injection process,the polymer chain is more likely to fold and crystallize when shorten injection time or increase injection rate,while packing pressure has little effect on the crystallinity.
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