Surface Modification of Nano-Sized Silicon Nitride with HFMA-MMA-VTMS Tercopolymer and their disperstion in FKM Composites

Abstract

In this work, a new macromolecular coupling agent HFMA-MMA-VTMS tercopolymer was synthesized using solution polymerization. The terpolymer's molecular structure was confirmed by FTIR and ¹H NMR and GPC. The HFMA-MMA-VTMS tercopolymer was used for surface modification of silicon nitride (Si₃N₄) nanopowder. The structure surface properties and thermal stability of modified nano-Si₃N₄ were systematically investigated by FTIR, size distribution analyzer, TGA, TEM and nano-Si₃N₄/FKM composite was investigated by SEM. The results show that the macromolecular coupling agent bonds covalently on the surface of nano-sized Si₃N₄ particles and an organic coating layer was formed. The optimum loading of this macromolecular coupling agent HFMA-MMA-VTMS tercopolymer was 12 % (wt %) of nano-sized Si₃N₄. TEM also reveals that modified nano-Si₃N₄ possesses good dispersibility. SEM reveals that modified nano-Si₃N₄ dispersed more finely and homogeneously in the FKM matrix.