Study on SiO₂/epoxy nano-composites preparation method based on under-expanding jet

In order to obtain suspended dispersion of nano-particles in liquid without the help of adding any dispersant, an under-expanded jet dispersion method for dispersing nano-particles in liquid was presented. In this method the nano-particles are distributed into the liquid in terms of gas-particles diminutive bubbles with the help of under-expanded jet, and then dispersed into particles with nano-scale in the liquid. The process is supported by the energy released from the diminutive bubbles explosion under high frequency extrusion, the high stretching field and ultrasonic effect generated in the bubble inflation. Corresponding dispersion system was designed and non-dispersant dispersion experiment for SiO₂ particles in epoxy resin was performed. The TEM image illustrates that the SiO₂ particles disperse in epoxy resin in a homogenous fashion with SiO₂ particles in the scale of 15-30 nm. T_g testing result indicates the T_g temperature of the SiO₂/epoxy nano-composites prepared by this method is about 18°C higher than that of prepared by conventional high speed mechanical agitation. The proposed method solves the problem of SiO₂ nano-particles aggregation in epoxy resin.