Effect of silica particles on vulcanization performance, viscoelasticity and cell structure of EPDM

Abstract

Four different types of silica particles (A200, H2000, R812S, T36-5) were used as reinforcing fillers for EPDM to prepare microcellar EPDM foams by supercritical CO2. The viscoelasticity, vulcanization and cell structure of different silica were tested and characterized by scanning electron microscope and rubber processing analyzer. The results show that the EPDM matrix has good rheological property with fumed silica (A200, H2000, R812S) as reinforcing filter, which is conducive to the formation of cell structure and the cell density is increased with the increase of the degree of crosslinking. The modulus and viscosity of the EPDM matrix with silica T36-5 matrix as the reinforcing filler by using precipitation method are too high, therefore the cell structure is formed only in narrow pre-vulcanization interval. Among them, the EPDM matrix with silica A200 as the reinforcing filler can obtain a high degree of cross-linking without losing good rheological properties, and A200 can provide better heterogeneous nucleation, and significantly improve cell density and reduce cell size.

Keywords

• silica
• ethylene-propylene-diene-monomer
• rubber foam
• supercritical carbon dioxide