Preparation of stable biopolymer composite suspension with metal/metal-oxide nanoparticles

Hydroxypropyl methylcellulose (HPMC) is a kind of biopolymer that is biodegradable, environmentally friendly and possesses exceptional mechanical and tribological properties. Therefore, it could be used as a suitable alternative to plastic. However, HPMC deforms easily when subjected to loads, causing higher real contact area and adhesive force between HPMC and grinding counter. Therefore, HPMC films are easily damaged because of adhesive wear, which negatively affects wear resistance. Hence, nanoparticles (NPs) of Al, Cu, Al2O3 and CuO have been used as fillers to increase the wear resistance of the HPMC composite films. The uniform dispersion of NPs in the suspension is the most important factor, which is greatly related to the wear resistance after film formation. Nanosuspensions with various dispersant concentrations were prepared, and mixed with the HPMC solution to prepare composite solutions and composite films. The results showed that Span 80 could provide steric stabilization, and that it dispersed the NPs effectively in suspension. After mixing the suspension with the HPMC solution, the solution became more stable.