材料期刊网

以纳米CaCO3浆料和丁苯胶乳、羧基丁苯胶乳、丁腈胶乳为原料，采用共凝聚法分别制备了三种纳米CaCO3-粉末橡胶复合粒子，并制备了三种纳米CaCO3-粉末橡胶／聚氯乙烯（PVC）复合材料，系统研究了复合粒子含量对PVC力学性能的影响，并探讨了复合粒子的增强增韧机制。结果表明：复合粒子在PVC树脂中分散均匀，复合粒子中的纳米CaCO3粒子以“裸露态”和橡胶“包裹态”两种形式存在于PVC基体中；三种复合粒子均能显著提高PVC的缺口冲击强度，纳米CaCO3-粉末丁腈橡胶（CaCO3-NBR）能同时起到增强增韧的效果，而纳米CaCO3-粉末丁苯橡胶（CaCO3-SBR）在提高缺口冲击强度的同时也损失了PVC原有的刚性，使其弯曲模量和拉伸强度大幅度降低，纳米CaCO3-粉末羧基丁苯橡胶（CaCO3-X—SBR）的改性效果鉴于前两者之间；复合粒子与PVC基体的相容性是影响复合粒子增强增韧改性效果的决定性因素，相容性好的复合粒子能同时起到增强增韧的效果。

Three types of nano-CaCO3 filled powdered rubber composite particles were prepared by coagulation method using nano-CaCO3 and latices as raw materials. The influence of the content of the composite particles on the mechanical properties of polyvinyl chloride (PVC) and their different reinforcing and toughening mechanisms were investigated. TEM micrographs show that the composite particles disperse well in the PVC matrix, where the nano-CaCO3 particles exist either uncovered or embedded in the rubber continuum. It was demonstrated that all three composite particles can dramatically increase the notched impact strength of PVC, among which nano-CaCO3 filled powdered acrylonitrile-butadiene rubber (CaCO3 -NBR) can achieve high stiffness and toughness. While nano-CaCO3 filled powdered styrene-butadiene rubber (CaCO3 -SBR) improves the impact resistance at the cost of decrease in stiffness, resulting in the significantly decreasing of flexural modulus and tensile strength. The modification effect of nano-CaCO3 filled powdered carboxylated styrene-butadiene rubber (CaCO3 -X-SBR) is between CaCO3 - NBR and CaCO3 - SBR. The results also show that the compatibility between the composite particles and PVC is the key point for the reinforcing and toughening effect. The composite particles with good compatibility with PVC matrix demonstrate better synergistic reinforce and toughen effect than the ones with bad compatibility.