New Progress in the Carbon Black Reinforcement of Rubber: (Part 2): The Interface between Carbon Particles and Rubber Confirmed through the Newest Observation

Abstract

The newest observation with optical methods showed the clear image of the interface between carbon particles and rubber. Carbon particles in the filled rubber vulcanizate are surrounded by the double layers of uncross-linked bound rubber, GH and SH layers, 10 nm in the total thickness. Fine carbon blacks and their aggregates connect together each other and form the super network by the interconnection of SH layers, thus the co-continuous structure of the super network and matrix cross-linked rubber supports the stress of the system. Under large extension, molecules in the SH layer are finitely extended through sliding and orientating and change to the strands of extended molecules between carbon particles. This behavior generates the stress-upturn and energy dissipation in the system simultaneously, and finally results in Mullins effect together with the buckling of the super network. The stress-strain curve of the filled rubber can be yielded as the incorporated curve of the Gaussian at a smaller extension than a critical strain and the non-Gaussian at the larger extension.