An effective way to stabilize silicon nitride nanoparticles dispersed in rubber matrix by a one-step process

In this work, a new graft copolymerization macromolecular coupling agent (LMPB-g-MAH) of maleic anhydride (MAH) onto low-molecular-weight polybutadiene liquid rubber (LMPB) was synthesized, and it was used to modify silicon nitride nanoparticles (Si3N4). The structure and surface properties of modified nano-Si3N4 were systematically characterized by FTIR, TEM, XPS, size distributions analyzer, TGA, dispersion stabilization in dimethylbenzene and contact angle measurement. It can be found that the optimum graft degree (GD%) and loading of LMPB-g-MAH is 9–11% and 10–12%, respectively. According to the spectra of FTIR and XPS, it can be inferred that LMPB-g-MAH covalently bonds on the surface of nano-Si3N4 particles and an organic coating layer was formed. The contact angle and surface free energy experiments show that the hydrophobic property of modified nano-Si3N4 is improved. TEM reveals that modified nano-Si3N4 possesses good dispersibility and the average diameter in dimethylbenzene is less than 60 nm. TGA indicates that the using efficiency of the macromolecular coupling agent is 44.66%. The oil resistance of SBR-based nanocomposites was also studied, which was improved greatly due to the modified nano-Si3N4.