Preparing process on toughening and strengthening cyanate ester with Nano-SiO₂

SiO₂/cyanate ester (CE) nano-composites were prepared in situ polymerization, and three different methods of dispersing nano-SiO₂ (attrition treatment, coupling agent surface treatment, highspeed homogeneous shearing) were investigated. Nano-particle dispersion, mechanical and thermal properties of nano-composites under three dispersing methods were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The characterization results showed that attrition treatment produced nano-composites with more excellent nano-particle dispersion than high-speed homogeneous shearing, however, coupling agent surface treatment couldn't disperse SiO₂ in nanometer size range. High-speed homogeneous shearing better improved mechanical and thermal properties of composites, and when nano-SiO₂ was 1phr (per hundred resin),the impact strength and the flexural strength of composites were respectively 35.0% and 12.1% higher than pure CE; and when the mass loss of composites was 5%, its degradation temperature improved 23.8°C compared with pure CE. Coupling agent surface treatment decreased the flexural strength and degradation temperature of composites.