Study On Characterization Of Si₃N₄/CSM Nano-composites

Rubber nano-composite is a kind of novel composite which is made of rubber as matrix, and nano-particle as dispersed phases with at least one dimension size less than 100nm. In this paper, we prepared nano-SiaN4/CSM composites,and then discussed the effect of nano-Si3N4 modified by macromoiecular coupling agent to properties of the nano-composites.1. Low-molecular-mass CSM(LMCSM)was prepared by degrading CSM in open mill, the number average molecular weight of LMCSM was characterized by mooney viscosity and VPO then was used to modify nano-Si3N4. FT-IR,TGA indicated that LMCSM bonded covalently on the surface of Si3N4 nanoparticles. From TEM observation, it was found that lower the number average molecular weight of LMCSM can improved the dispersibility of nano-Si3N4 particles in chloroform. Contact angle and surface energy measurement showed that the hydrophile and surface energy were decreased. The surface free energy of modified nano-Si3N4 decreased from 319.04J/M2 to 66.89J/M2.TGA indicated that chemical modification was primary, the maximum chemistry and the minimum physics usage efficiencies of the macromolecular coupling agent was 42.49% and 14.64%, respectively.2. LMCSM-Si3N4/CSM composites were prepared by blending techniques, the performance of nanocomposites were analyzed and discussed by stretching apparatus and RPA-8000.The results showed that nano-Si3N4 powder before or after modification by CSM can reduce cure time and plastic burning time of the composites, when nano-Si3N4 powder was modified by LMCSM can increase cure time and plastic burning time of the composites. Nano-Si3N4 can reinforce the mechanical properties of nanocomposites. The results of dynamic mechanical properties examination indicated that low average molecular weight of macromolecular coupling agent can improve dispersion of powders in the CSM matrix more effectively. When the loading of modified nano-Si3N4 was 1.0%, nanocomposites achieved the best performance. 3. The modified powder LMCSM-Si3N4 which dispersed in the plasticizer(TOTM) fully was used to prepare nanocomposites.The results showed that the loading 2.0% of modified nano-Si3N4 had the best dispersion in the CSM matrix, and could improve the performance of nanocomposites, and could reduce the loss tangent of nanocomposites further.