加入不同种类成核剂抗冲击共聚PP的非等温结晶动力学

Non-isothermal crystallization kinetics of impact PP copolymer with different nucleating agents

采用差示扫描量热仪研究了加入羧酸盐类成核剂和有机磷酸盐类成核剂的抗冲击共聚聚丙烯2500H的熔融、结晶和非等温结晶行为。结果表明：加入质量分数为0.02%的成核剂后,2500H的结晶度和所有结晶特征温度均提高,其中,结晶度提高0.3%-3.0%,结晶温度提高4.4-11.0℃,结晶起始温度提高4.4-12.2℃,结晶终止温度提高6.3-11.6℃。与加入有机磷酸盐类成核剂的2500H相比,加入羧酸盐类成核剂的2500H具有更低的结晶过冷度,成核能力相对较高;但加入有机磷酸盐类成核剂的2500H表现出更快的结晶速率,而加入羧酸盐类成核剂的2500H虽然在高温条件下能促使2500H较快形成晶核,但并不利于结晶速率的提高。

Melting,crystallization and the non-isothermal crystallization process of copolymerized impact polypropylene（PP）2500H nucleated by carboxylic acid salts nucleating agent and organic phosphate nucleating agent were studied by means of differential scanning calorimeter（DSC）. The results show that the crystallinity and all crystallization characteristic temperatures of 2500 H are improved when the mass content of the nucleating agents was 0.02%,the crystallization degree is increased by 0.3%-3.0%,the crystallization temperature is increased by 4.4-11.0 ℃,the onset crystallization temperature is increased by 4.4-12.2 ℃,and the end crystallization temperature is increased by 6.3-11.6 ℃. The PP nucleated by carboxylic acid salts nucleating agent has lower undercooling than the PP nucleated by organic phosphate nucleating agent,so the former shows a relatively higher nucleation capability. However,the PP with organic phosphate nucleating agent has higher crystallization rate,while the carboxylic acid salts nucleating agent is not beneficial to the improvement of crystallization rate though it can quickly make 2500 H form crystal nucleus at high temperature.