Reinforcement and migration of nanoclay in polychloroprene/ethylene-propylene-diene-monomer rubber blends

This communication demonstrates, an approach of compatibilization between polychloroprene (CR) and ethylene propylene diene monomer rubber (EPDM) by using nanoclay as a compatibilizer and, simultaneously, as a very strong reinforcing nano-filler. With the incorporation of less than 9 wt.% nanoclay, the dynamic storage modulus above the glass transition region of such a blend increases from ∼2 MPa to ∼54 MPa. This tremendous reinforcing as well as the compatibilization effect of the nanoclay was understood by thermodynamically driven preferential framework-like accumulation of exfoliated nanoclay platelets in the phase border of CR and EPDM, as observed i.e. from transmission electron microscopy. The extra-ordinary improvement of dynamic modulus can also be understood by a very strong filler-filler networking that we observed in strain sweep experiments. Moreover, we found that the compatibilized blends exhibit an extra dynamic-mechanical relaxation process at higher temperatures (∼T_g + 130 K). The suggested method for compatibilization of incompatible rubber blends offers routes to the design of new rubber based technical products for diversified applications.