Dynamic mechanical properties and hysteresis loss of epoxidized natural rubber chemically bonded to the silica surface

High-temperature (180degreesC) molding of epoxidized natural rubber (EN-R) filled with precipitated silica leads to chemical bond formation between epoxy groups of ENR and silanol groups of silica. The extent of chemical bond formation is further enhanced in the presence of the silane coupling agent N-3-N-(vinyl benzyl amino)ethyl-gamma-amino-propyl trimethoxy silane mono hydrogen chloride (trade name Z-6032). The results of hysteresis loss measurements show that hysteresis loss increases with increase in coupling agent loading as a result of the higher modulus of the compounds compared to that of the ENR-silica mix. The dynamic mechanical property measurements show that the addition of coupling agent increases the glass-transition temperature. Whereas strain-dependent dynamic mechanical properties show that filler structure breakdown increases with increasing loading of coupling agent. Sulfur-cured systems show higher filler structure breakdown compared to that of nonsulfur systems. (C) 2002 Wiley Periodicals, Inc.