【摘要】 对加入有效成核剂 (加入量为 0 .1%～ 2 .0 % )的聚丙烯材料进行了缺口冲击实验 ,发现其冲击强度在成核剂加入量 0 .4 %处出现极大值 ,通过测定其结晶度和球晶尺寸的变化发现 ,当有效成核剂加入量小于 0 .4 %时 ,随加入量增大 ,球晶尺寸呈下降趋势 ,结晶度呈上升趋势 ;当有效成核剂加入量大于0 .4 %时 ,随加入量增大 ,球晶尺寸的下降趋势变小且逐渐趋于稳定 ,而结晶度仍呈上升趋势。另一方面 ,通过断口观察和分析发现 ,其断面形态特征参量——扩展区的断面分形维数随成核剂加入量的变化与结晶形态和冲击强度的变化相对应 ,即在成核剂 0 .4 %加入量处出现极大值。实验结果分析表明 ,通过加入某种有效成核剂与 PP共混 ,其结晶形态的变化与其冲击强度的变化相对应 ,并且这种对应关系通过断面特征形态尺寸的变化反映出来更多还原

【Abstract】 A series of notched impact tests were made to PP materials with certain an effective nucleating agent filled( 0.1 mass%~2 mass%). A maximum of impact strength exists in at the 0.4 mass% filled quantity of the nucleating agent. It was showed that while the filled quantity of the nucleating agent is below 0.4 mass%, the spherulite size decreases, the crystallinity increases, the impact strength is controlled mainly by the spherulite size, but when it is beyond 0.4 mass%,the decline tendency of the spherulite size decreases and tends towards stabilization progressively, the crystallinity still increases, the crystallinity is the decisive factor to strength property. This illustrates that appearance of the maximum of impact strength is due to the comprehensive result of the spherulite size and the crystallinity. The fracture surface are composed of the expand zone,the arc stripe zone and the last fracture zone. The fractal dimension of the expand zone exists a maximum at the 0.4 mass% filled quantity of the nucleating agent, the size of arc stripe has nothing to do with the quantity of nucleating agent.更多还原