In this work, the nano-SiO2 was firstly modified by silane coupling agent (3-aminopropyltriethoxysilane), meanwhile the dispersion of nanoparticles was studied with transmission electron microscope (TEM). Then urea-formaldehyde (UF) resins were synthesized and modified with the compound modifier made of different ratio of modified nano-SiO2 and oxidized starch. All the products were characterized with Fourier transform infrared spectroscopy (FTIR). Free formaldehyde content and bonding strength were measured as the main standard of the performance of the resin. The other performances of modified UF resins were also analysized by X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The results showed that the modification could effectively reduce the free formaldehyde content, from 0.49 to 0.19%, and enhance the bonding strength, from 0.90 to 2.06 MPa.

Keywords: urea-formaldehyde resin; silane coupling agent; oxidized starch; free formaldehyde content; nano-SiO2