Strikingly Improved Toughness of Nonpolar Rubber by Incorporating Sacrificial Network at Small Fraction

It poses a huge challenge to create nonpolar rubber with high fracture toughness. In the present letter, inspired by the concept of sacrificial bonding associated with many biological materials, we propose that a small fraction of additional sacrificial network can strikingly improve the fracture toughness of nonpolar rubbers. As a proof of concept, we created the additional fragile epoxidized natural rubber (ENR) network in commercially available SBR rubber in a facile process. With addition of only 10 phr ENR, the SBR/ENR double network (DN) exhibits a fracture energy nearly fourfold higher than that for the neat SBR. The formation of DN formation and the correlation between the high toughness and presence of the second brittle network have been fully discussed. This is the first time sacrificial networks are created in diene-based rubber towards high toughness elastomers in a facile and efficient way. (C) 2015 Wiley Periodicals, Inc.