成核剂CDBS和纳米碳酸钙对聚丙烯结晶行为和力学性能的影响

Effects of Nucleating Agent and Nano-Calcium Carbonate on Crystallization Behavior and Mechanical Properties of Polypropylene

研究了聚丙烯(PP)中同时加入成核剂1,3;2,4-对氯二苄叉山梨糖醇(CDBS)和纳米碳酸钙(nm-CaCO3)后的等温结晶和非等温结晶过程的结果表明,加入纳米碳酸钙可有效提高PP的结晶温度和结晶速度,对结晶度没有明显的影响。成核剂的加入,使PP的结晶温度提高了约20℃,结晶速度明显加快,结晶度明显提高(达38%)。XRD和PLM观察表明,PP中加入成核剂后,成核密度增加十分显著,晶型没有明显变化,只是α晶型的晶面生长出现择优取向。加入成核剂的PP雾度由56%降低到12%,成核剂CDBS对PP具有很好的增透效果。力学性能测试显示,纳米碳酸钙和成核剂的加入使PP的抗冲击强度从33 J/m增加到约44 J/m,但CDBS的加入使PP的断裂伸长率由153%降低至127%。

The nucleating agent 1, 3; 2, 4-di-p-chlorinbenzylidene sorbitol （CDBS） and nano-calcium carbonate（nano-CaCO3） were added in polypropylene（PP）. The results of DSC indicate that the crystallization rate and the crystallization temperature of PP increased with the addition of nano-calcium carbonate particles, while the crystallinity of PP did not change obviously. The crystallization temperature of PP with nucleating agent CDBS was higher than that of non-nucleated PP by about 20 ℃. The crystallization rate and the crystallinity of PP increased with the addition of CDBS, with the crystallinity of PP reaching 38%. The results of XRD and PLM show that the nucleating density increased obviously when CDBS was added into the samples. But the crystal structure of the a-form of polypropylene was essentially unaffected by the nucleating agent. CDBS was an effective nucleating agent for PP. The haziness of tile sample decreased from 56% to 12% with the addition of CDBS and CDBS was a good transparent agent for PP. The nucleating agent and the nanoparticles could increase the tensile strength and impact strength of PP. The impact strength of PP increased from 33 J/m to about 44 J/m. But CDBS reduced the ultimate strain of the sample by about 26%.