Study On Dispersion Technology Of Nanoscale Powder In Silicone Rubber Matrix

The properties of the silicone rubber-based nanocomposites are closely related to the dispersion of nanoscale powder in the silicone rubber matrix,so it is of great significance to find the way to improve the dispersion of nanoscale powder.This paper is divided into two parts.In the first part,we utilized a"wet" treatment method to modify nano-CaCO₃ with four kinds of fatty acids?stearic acid,oleic acid,palmitic acid,lauric acid?,and blended the surface modified nano-CaCO₃ with RTV silicone rubber matrix to prepare RTV silicone rubber nanocomposites.We investigated the effect of surface treatment by fatty acids of different kinds and different dosages on the dispersion state,rheological and mechanical properties of silicone rubber-based nanocomposites,and discussed the mechanism of surface modification.The results of experiments reveal that the four kinds of fatty acids,stearic acid,oleic acid,palmitic acid and lauric acid,can cover the surface of nano-CaCO₃ particles,change the surface properties of nano-CaCO₃ powder,thus reduce the agglomeration of nano-CaCO₃ particles in the silicone rubber matrix,improve the dispersion uniformity of nano-CaCO₃ particles,and then improve the rheological properties and mechanical properties of silicone rubber-based nano-CaCO₃ composites.On the other hand,by comparing the properties of modified nano-CaCO₃ powder,we found that the more surface modifier is used,the better the surface modification effect of nano-CaCO₃,the better the surface hydrophobicity of nano-CaCO₃,the better the dispersion of nano-CaCO₃ in the silicone rubber matrix,the better the rheological and mechanical properties of the silicone rubber-based nano-CaCO₃ composite.Therefore,the best dosage of four fatty acids to modify nano-CaCO₃ is 2%.And the best kind of fatty acid to modify nano-CaCO₃ is stearic acid,so in this study,2.0%SA-CaCO₃?nano-CaCO₃ powder modified by 2%stearic acid?is the modified nano-CaCO₃ powder with the best comprehensive performance.In the second part,we compared the properties of 2.0%SA-CaCO₃ with three kinds of marketed nano-CaCO₃ powder modified by stearic acid,which can be used to evaluate the technical level of the surface modified nano-CaCO₃ powder prepared in this study.The experimental results show that the dispersion of 2.0%SA-CaCO₃ in the silicone rubber matrix and the improvement of the rheological properties and mechanical properties of the silicone rubber-based nano-CaCO₃ composites have exceeded the domestic marketed nano-CaCO₃ powder modified by stearic acid in the case of using relatively less surface modifier.