Design of Vulcanization Intermediates with Low Steric Hindrance Contributing to Vulcanization Network Formation

Abstract

Sulfur cross-linking, known as vulcanization, is an extraordinarily important process to endow rubbers with practical performances in the rubber industry. However, the steric hindrance of vulcanization intermediates hinders the formation of vulcanization networks, limiting the property enhancement of vulcanized rubbers. To promote the formation of vulcanization networks, our group lowers the steric hindrance of vulcanization intermediates through decreasing the length of alkyl chain. Temperature-dependent Fourier transform infrared spectroscopy suggests the formation of bridging bidentate zinc/fatty acid salt complex (vulcanization intermediates) with different steric hindrances. The reduction in steric hindrance of vulcanization intermediates increases the coordination interactions between sulfur and vulcanization intermediates, promoting the ring-opening of sulfur and formation of vulcanization networks. As a result, with the reduction in steric hindrance of vulcanization intermediates, the properties of vulcanized rubbers improve greatly. This work promotes the formation of vulcanization network through lowering the steric hindrance of vulcanization intermediates, which provides a simple generic strategy for the development of high-performance rubbers.