Preparation of Ureido-palygorskite and its effect on the properties of urea-formaldehyde resin

An Ureido-palygorskite (Ureido-PA) was developed by grafting γ-ureidopropyltriethoxysilane (UPTES) to PA to improve the performance of urea-formaldehyde resins (UF). The Ureido-PA was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and thermogravimetric-differential thermal (TG-DTA). UPTES was grafted onto the surface of palygorskite (PA) by chemical bonding. The effect of PA on the free formaldehyde content, the shear strength, and the water-resistance of UF resins was investigated. The free formaldehyde content of the composites was less than 1% and the shear strength was double of that of the pure UF resins when the dosage of Ureido-PA was 9% of net formaldehyde and urea (in total mass). The influences of PA on the thermal stability and the morphologies of the composites were also studied by derivative thermogravimetric (DTG) and transmission electron microscopy (TEM).