顺式1,4-聚丁二烯的流变性质——Ⅰ.流动曲线的不连续性

用毛细管流变仪测定了四种不同催化体系高顺式1,4-聚丁二烯的流动曲线。流动曲线由连续变成不连续的临界温度随顺式含量的增加而增高。并发现长链支化也起重要作用,线性程度愈好则临界温度也愈高。挤出物的不同形状可作如下描述:流动不稳定性可独立地发生于口模入口、口模出口及模壁,但滑移本身并不导致外形不规整。

RHEOLOGICAL PROPERTIES OF CIS 1,4-POLYBUTADIENESⅠ. DISCONTINTJITT OF FLOW CUBVES

The flow curves of cis 1,4-polybutadiene prepared by four different catalytic systems have been measured by a capillary rheometer.The critical temperature at which the flow curves change from continuousness to discontinusness increased as the cis content increased. It was also found that the long chain branching plays an important role, the better the linearity the higher the critical temperature. The different shapes of extrudate were well explained in the light of the picture that the flow instability can occurs independently at the die-entrance,die outlet and die wall,but the slippage ltself gives no contribution to the irregu-alrity of the extrudate.