纳米碳酸钙表面改性及其对聚丙烯复合材料增韧的研究

将纳米碳酸钙通过湿法改性后,加入PP/SBS体系中,以实现无机纳米粒子增韧.结果表明,经表面改性的纳米碳酸钙可以很好地提高PP/SBS体系的韧性,使其冲击强度在常温和低温下分别增加42.58%和112.5%.实验发现改性纳米碳酸钙表面所包覆改性剂的分子结构,对其增韧效果有决定作用,而改性剂包覆的多少只起次要作用.

Surface modification of nano-CaCO3 and toughness of polypropylene composite materials

The nano sized CaCO₃ particles (30 nm in mean size) were modified with different chemicals and then filled into PP/SBS polymer system in order to increase the toughness of PP. The results show that the surface treated nano CaCO₃ is able to increase the toughness of PP/SBS system very well, with an increase of 112 .5% at low temperature (-10℃) and 42.58% at room temperature , respectively. Moreover , it is found that the key factor to increase the toughness with inorganic particles is to select the modifiers , which have a decisive effect on the surface property of particles. For instance , nano2CaCO3 t reated with titanium coupling agent and stearic acid was respectively put in cyclohexane (non2polar solvent) and chloroform (polar solvent) to test sedimentation volume. The result s are quite different . The nano2CaCO3 with big sedimentation volume in cyclohexane increases the toughness of PP well , which molecular has non-polar property either. By comparison , the nano-CaCO₃ with the highest activity content and big sedimentation volume in chloroform does not increase PPpstoughness well. So it is clear that the selection of modifiers , having similar molecular st ructure as PPps molecule aCH(CH₃) CH₂ e , has decisive effect on the toughness of PP and the adsorption amount of the modifier only plays a minor role.