Studies On Modified Multi-walled Carbon Nanotubes And Urea-formaldehyde Resin Adhesive

Carbon nanotubes (CNTs) become a hot spot of current reasearch due to its excellent mechanical and electrical properties, but CNTs tend to agglomerate into bundles because of high surface energy, which limits their wide application; Urea-formaldehyde (UF) resin adhesive is a major adhesive in the wood industry, while many studies committed to investigate the methods to overcome its disadvantades, such as lower bonding strength and release of free formaldehyde. In this paper, we used mechanical mixing to prepare multi-walled carbon nanotubes (MWNTs)/UF resin composites, expecting CNTs can improve the properties of composites.1. MWNTs were treated by concentrated sulfuric acid and nitric acid (Volume ratio=3:1) with the aid of ultrasonication. Using the anlysis instructment of FT-IR, XRD, TG, SEM, we found that the structure of MWNTs were not destroyed, carboxylic acid was introduced on the surface of MWNTs, and there was almost no presence of amorphous carbons or catalyst particles.2. The dispersion of modified MWNTs in alkaline aqueous solution assisting with sodium dodecyl sulfate (SDS) and cetyl trimethyl ammonium bromide (CTAB) were analyzed by UV-Vis spectrophotometer. The results shows that, the concentration of MWNTs in SDS aqueous solution had minimal change after centrifugation, so SDS shows good dispersion.3. The shear strength of MWNTs/UF resin composites increased by90%compared to the pure UF; the content of MWNTs had little effect on the release of free formaldehyde. The composites had lower decomposition rate and better thermal stability than UF by using of TG. The dispersion of MWNTs in UF resin was not uniform by SEM.