Mechanical Properties of Nanocomposites from Ball Milling Grafted Nano-Silica/Polypropylene Block Copolymer
Mechanical Properties of Nanocomposites from Ball Milling Grafted Nano-Silica/Polypropylene Block Copolymer
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DOI：
10.1177/096739110401200401
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发表时间：
2004-05
影响因子：
2.1
通讯作者：
W. Ruan;M. Zhang;M. Rong;K. Friedrich
中科院分区：
文献类型：
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作者：
W. Ruan;M. Zhang;M. Rong;K. Friedrich
采用传统的复合技术制备了纳米二氧化硅填充乙烯-丙烯嵌段共聚物的纳米复合材料。研究了纳米复合材料的力学性能和纳米粒子的加入引起的形态变化。证实了在球磨机中的机械化学接枝过程中，共聚物链化学键合到二氧化硅颗粒上。形态学观察揭示了接枝聚合物之间的强界面相互作用（即，聚（丙烯酸丁酯））和基质（即，乙烯-丙烯嵌段共聚物）对于发挥纳米颗粒的增强作用是关键的。由于界面相互作用的增强，接枝纳米粒子表现出成核效应，提高了聚合物基体的结晶度。此外，由于接枝聚合物与基体之间的缠结，粒子对无定形聚丙烯相也有增韧作用。纳米颗粒与共聚物基质的乙烯-丙烯橡胶相之间的不充分相互作用实际上引入了限制。因此，通过使用低负载量的经处理的纳米颗粒，可以显著增加纳米复合材料的拉伸强度和模量。与传统的微米级无机粒子填充复合材料相比，缺口夏比冲击强度的降低是微不足道的。因此，所提出的技术路线是可行的，制备聚合物复合材料与无机纳米粒子。
Nanocomposites consisting of ethylene-propylene block copolymer filled with nano-silica (pre-treated by ball milling aided graft polymerisation) were prepared by a conventional compounding technique. The mechanical performance of the nanocomposites and the morphological changes induced by the addition of the nanoparticles were investigated. It was confirmed that the copolymer chains were chemically bonded to the silica particles during mechanochemical grafting in the ball mill. Morphology observations revealed that strong interfacial interaction between the grafting polymer (i.e., poly(butyl acrylate)) and the matrix (i.e., ethylene-propylene block copolymer) is critical for bringing the reinforcing effect of the nanoparticles into play. Owing to the enhanced interfacial interaction, the grafted nanoparticles exhibited a nucleating effect and improved the crystallinity of the polymer matrix. In addition, the particles also had a toughening effect on the amorphous polypropylene phase because of entanglements between the grafting polymer and the matrix. Insufficient interaction between the nanoparticles and ethylene-propylene rubber phase of the copolymer matrix actually introduces restraints. As a result, the tensile strength and modulus of the nanocomposites can be significantly increased by using low loadings of the treated nanoparticles. The decrease in the notched Charpy impact strength was insignificant in comparison to that of conventional micron-scale inorganic particles filled composites. The technical route proposed is therefore feasible for fabricating polymer composites with inorganic nanoparticles.