Study of surface modification of nano-SiO2 with macromolecular coupling agent (LMPB-g-MAH)

Commercial silicon dioxide nano-particles were modified by graft copolymerization macromolecular coupling agents (LMPB-g-MAH) of maleic anhydride (MAH) onto low-molecular-weight polybutadiene liquid rubber (LMPB) in dimethylbenzene. The hydroxyl groups on the surface of nano-SiO2 particles can interact with anhydride groups [–(CO)2–O–] of LMPB-g-MAH and an organic coating layer was formed. The covalent bands [–(CO)–O–,–(CO)–NH–] formed was testified by Fourier transform infrared spectra (FT-IR). Through transmission electron micrograph (TEM) observation, it was found that LMPB-g-MAH improved the dispersibility of nano-SiO2 particles in dimethylbenzene. By using the particle size analysis, it was confirmed that the optimum graft degree (GD%) and the optimum loading of LMPB-g-MAH is 9–11%, 10–12%, respectively. The dispersion stabilization of modified SiO2 nano-particles in dimethylbenzene was significantly improved due to the introduction of grafted polymers on the surface of nano-particles. Thermo gravimetric analysis (TGA) and contact angle measurement indicated that LMPB-g-MAH molecules were absorbed or anchored on the surface of nano-SiO2 particle and the using efficiency is 74.66%, which facilitated to hinder the aggregation of nano-SiO2 particles.