有机小分子接枝炭黑填充PP复合材料的结晶行为与力学性能研究

Crystal Behavior and Mechanical Properties of PP Composites Filled with Carbon Black Grafted by Organic Small Molecules

将炭黑与有机小分子在Haake转矩流变仪中进行混合,通过高剪切力的作用,实现了有机小分子在炭黑表面的接枝改性。通过对比接枝改性后的炭黑(GCB)与接枝改性前的炭黑(CB)对聚丙烯(PP)性能的影响,发现GCB能更有效地促使PP基体发生异相成核,提高基体的结晶温度,使聚丙烯的韧性和强度都有明显提高。TEM结果表明,炭黑表面经过接枝有机小分子后粒径变小,在聚丙烯中能更好地分散。DSC结果表明CB和GCB对PP基体的结晶行为都会产生影响,但GCB的影响更加显著。添加1%GCB后,PP的结晶峰值温度提高了11.6℃。添加量仅为1%时,材料的缺口冲击强度,屈服强度和弯曲强度都有明显提高。

Carbon black and organic small molecules were mixed in a Haake Rheomix Mixer. The aggregated carbon black was broken apart by the powerful shear force and then grafted by the organic small molecules. The effect of grafted carbon black （GCB） on the properties of PP composites was studied and compared with that of carbon black without any treatment （CB）. It was found that GCB had more evident effect on providing nucleation sites and increasing the crystallization temperature of PP composite, and the toughness and stiffness of PP composites were also greatly improved. TEM results showed that the agglomerations of GCB particles into the PP matrix decreased in average size and the dispersion degree was greatly improved. DSC curves showed that both CB and GCB had influence on the crystal behavior of PP matrix, but the latter had more evident effect on providing nucleation sites and increasing the crystallization temperature. The addition of 1 wt% of GCB could increase the crystallization peak temperature by 11.6 ℃ at the cooling rate of 10 ℃/min in comparison with pure PP. With the addition of 1 wt% of GCB as filler, the charpy impact strength was greatly enhanced simultaneously with yield strength and flexural strength.