对不同类型炭黑补强SBR拉伸强度的研究表明,炭黑补强SBR中存在着类似于橡胶增韧塑料的逾渗现象,由此提出橡胶补强临界间距的新概念,并讨论其影响因素.对于炭黑补强SBR体系,存在的一个最大临界粒径(原生粒子直径)为80 nm左右.提出了界面相互作用和最小补强粒子尺寸等橡胶补强设计上的新观点.通过计算机模拟,在分子水平上对橡胶和纳米颗粒间的界面相互作用进行了深入研究,结果表明即使在很强的界面作用(氢键范围)情况下,靠近颗粒表面的分子链仍然具有一定的活动性,在界面处能发生吸附脱附的过程.从热力学和动力学的角度阐述了在颗粒的表面不太可能形成橡胶玻璃化壳层.%By studying the tensile strength of SBR reinforced by various types of carbon black, percolation phenomenon in the rubber nano-reinforcement was demonstrated, which was similar to the percolation behavior occurred in the rubber toughened plastics. The concept of critical particle-particle distance was hereby put forward for rubber reinforcement, and the factors which govern this critical particle-particle distance were discussed. Moreover, the concept of critical maximum particle diameter for reinforcement was also introduced (around 80 nm). Based on the percolation theory, some new viewpoints for reinforcement design of rubbery materials were put forward,including the interfacial interaction between rubber and nanoparticles and the smallest particle diameter for reinforcement. Meanwhile,this work also gained insight into the interfacial interaction between rubbery chains and nanoparticles at the molecular level through computer simulation, which indicated that the polymer chains in the vicinity of nanoparticles still possessed some mobility and underwent the adsorptiondesorption process, even for strongly attractive polymer-filler interaction(in the range of hydrogen bond). From the kinetics and thermodynamics points of view, the results clarified that it was impossible for polymer chains to be fully anchored on the nanoparticles surface to form the so-called “glassy layer” surrounding the nanoparticles.
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