Effect of low-cost mussel-inspired poly(catechol/polyamine) modification of waste brick powder followed by grafting of epoxy elastomers on natural rubber composites

The aim of this study is to explore a method for modifying waste brick powder (WBP) in order to reapply it to rubber products for effective resource recycling. Firstly, we use the auto polymerization of catechol/polyamine (CPA) on the surface of WBP to form a poly catechol/polyamine (PCPA) coating as an intermediate reaction platform. And then the macromolecular modifier, epoxy-functionalized elastomer (ethylene vinyl acetate-glycidyl methacrylate terpolymer) (EVMG), is further grafted onto the PCPA coating to prepare the WBP@EVMG hybrid materials. During the preparation of the WBP@EVMG hybrid materials, a ring-opening reaction between the amine group of PCPA and the epoxy group of EVMG occurs. The NR/WBP@EVMG composites are prepared by mechanical blending. The interfacial interactions between WBP@EVMG and NR are analyzed and verified in detail by dynamic mechanical analysis (DMA) and rubber process analyzer (RPA). It is shown that the modified NR/WBP composites show increased vulcanization rate and better mechanical properties, and the tensile strength, abrasion resistance, cracking strength, and wet slip resistance of NR/WBP@EVMG-15 are increased by 29%, 6%, 16%, and 11%, respectively, compared with that of NR/WBP composites, which provides a unique idea for the reuse of waste brick powder in rubber.