Mechanical and dismantlement adhesion properties of grafted EPDM-silica hybrid

This study was carried out to confirm the effects of functional groups that could derive secondary bonding and silica contents on mechanical properties and thermo-reversible characteristics of grafted EPDM-silica composites, which was produced by blending silica or introducing silica hybrid through ionic bonding after grafting methacrylic acid onto EPDM. The storage modulus of graft copolymer had appeared to be higher than cross-linked EPDM vulcanizate at room temperature, and decreased by a gentle slope as temperature increased, and then began to decrease more sharply as secondary bonding force became weaker at higher temperature. When silica hybrid was introduced through ionic interaction, storage modulus and mechanical properties were found to be higher due to not only hydrogen and ionic bonding, but also nanosized silica particles, which were bonded to the elastomer structure in uniformed distribution. When the graft copolymer had only hydrogen bonding, recycling of the elastomer caused mechanical properties to be reduced by 20–30%. However, the recycling characteristics of elastomers having both hydrogen and ionic bonding were excellent as more than 90% of their initial mechanical properties were maintained even after five times of reprocessing. Graft copolymer composite had better adhesion strength with other rubber due to increased polarity than EPDM, and dismantlement of bonded adherends was possible by applying heat treatment of microwave.