Study of Surface Modification of Nanosize Si₃N₄with Macromolecular Coupling Agent LMPB-g-GMA in Different Solvents

Abstract

A new macromolecular coupling agent, low-molecular-weight polybutadiene liquid rubber (LMPB)-glycidyl methacrylate (GMA), was synthesized using solution polymerization initiated by benzoyl peroxide (BPO). The molecular structure was confirmed by FTIR and NMR. This macromolecular LMPB-GMA was used for surface modification of silicon nitride (Si 3 N 4 ) nanopowder in n-heptane, chloroform, ethyl acetate, and DMF, respectively. LMPB-GMA and modified nano-Si 3 N 4 were systematically investigated by FTIR, NMR, TGA, and TEM. The results showed that LMPB-GMA bonded and formed an organic coating layer onto the surface of nanosized Si 3 N 4 particles. The polarity of the solvents plays an important role in this process. Strong or weak polar both affect the results. The dosage loading of LMPB-GMA is 12 wt% of nanosized Si 3 N 4 . Nanosized Si 3 N 4 modified in ethyl acetate has better dispersibility and stability than that modified in n-heptane or DMF. TEM pictures also reveal that modified nano-Si 3 N 4 possesses good dispersibility.