Characterization of Phase Separated Structure and Interface In Rubber Blends by AFM

Rubber products consisted of polymer blends and inorganic additives have two kinds of interface, such as the interface between different polymers and between polymers and inorganic additives. In this study, the interface of phase separated structure of rubber blends, IR/BR and NBR/SBR, prepared by solvent casting, was characterized by AFM, SAXS and DSC. The thickness and the concentration profile of the interfaces were evaluated by the line analysis of AFM phase images and the mass fraction of the interfaces was determined by DSC. The phase image of IR/BR blends indicated that the interface had a continuous concentration change between IR and BR phases. The thickness and mass fraction of the interface between IR and BR phases depended on BR content. However, the morphology of phase separated structure and the thickness of interface were influenced by casting solvents for NBR/SBR. The concentration profile of the interface in NBR/SBR was more complex than that in IR/BR. The interface thickness of NBR/SBR depended on the size of phase separated domains and the solvents. The interface difference between IR/BR and NBR/SBR was discussed from the view point of the phase separation mechanism.