Effect of N, N′-m-phenylene bismaleimide on mechanical performance of waste rubber powder sintered by high-pressure high-temperature method

Waste rubber with three-dimensional structure is insoluble and non-melting, which creates recycling problem. The technique called “high-pressure high-temperature sintering” (HPHTS) can convert vulcanized rubber powder into usable rubber products. However, reversion occurs when vulcanizates are exposed to a prolonged treatment at high temperature. This reversion results in the decrease of mechanical properties of sintered waste rubber powder (WRP) samples. To address this problem, a method of enhancing the mechanical properties of sintered WRP by incorporating different content of maleic anhydride (MA) and N , N ′- m -phenylene bismaleimide (BMI) is discussed in this paper. The results show that BMI and MA can slow down the formation of the conjugated double bonds. Through Diels–Alder reaction, BMI inhibits conjugated double bonds formation and improves the adhesion between particles and particles, which is beneficial to improvement of final properties. Therefore, BMI improves the mechanical properties of sintered WRP greatly.