生胶挤出中的动态结晶及应力振荡行为

DYNAMIC CRYSTALLIZATION AND STRESS-OSCILLATION DURING EXTRUSION OF RUBBER COMPOUNDS

用Instron毛细管流变仪研究了NR、BR和NR/BR并用胶的流动行为,讨论了一定条件下形成不稳定流动的原因及影响因素。发现在较低温度下NR由于动态结晶而产生压力突增现象及不规则应力振荡;在较高温度下BR由于粘滑效应而产生规则应力振荡。这两种振荡都不可能在一般加工温度和剪切速率范围内完全加以避免,因此采用NR/BR并用胶是解决高含胶率胶料稳定挤出的有效途径。

The flow properties of natural rubber ( NR ) , polybutadiene rubber ( BR ) , and their blends ( NR/BR ) were studied by using Instron capillary rheometer, and the reason that causes the unstable flow of these compounds during extrusion was investigated. It is found that for NR, a sharp increase in pressure and irregular stress-oscillation are observed during the extrusion at lower temperatures because of dynamic crystallization of NR; while at higher temperatures a regular stress-oscillation is observed on ...