| 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 adsorption-desorption 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. |
