Synthesis of a coupling agent containing polyurethane chain and its influence on improving the dispersion of SiO2 nanoparticles in epoxy/amine thermoset

SiO2 nanoparticles (NPs) were modified with as-synthesized coupling agent containing isocyanate-terminated polyurethane (PUCA) to enhance the interaction between SiO2 NPs and DGEBA/DDM matrix in purpose of promoting the dispersion condition of the SiO2 NPs in cured resin. Uniform dispersion of the PUCA-SiO2 NPs was observed in the cured resin which was in obvious contrast with that of the raw SiO2 NPs and the IPTS-SiO2 NPs according to the visible light transmittance and TEM observation. The tensile behaviors of the PUCA-SiO2 composites were found obviously promoted than that of the raw SiO2 and IPTS-SiO2 composites. DMA results showed that the T-g of the PUCA-SiO2 composite was 8.9 degrees C and 5.8 degrees C higher than that of the raw, IPTS-SiO2 composite. SEM observation of the fracture surfaces showed that PUCA-SiO2 composite possessed the densest crack texture. This work showed that grafting the polyurethane chain to the surface of the inorganic NPs is an effective way to obtain uniform dispersion of the inorganic NPs in resin matrix.

Automated summary

Grafting the polyurethane chain onto the surface of SiO2 nanoparticles is an effective method to achieve uniform dispersion of the nanoparticles in the resin matrix, improving both dispersion and mechanical properties of the composite material.