Enhancing environmental performance of formaldehyde-based adhesives in lignocellulosic composites, part III: evaluation of some starch derivatives

Lignocellulosic composites are generally bonded using urea-formaldehyde as adhesive. A major drawback of this system is the continued release of formaldehyde during use. This study focused on evaluating some starch derivatives as scavengers of free formaldehyde. The modification of starch involved the reaction with acrylonitrile using grafting and Michael addition processes. Derivatives of cyanoethylated starch (propionamide ether and amidoximated starch) were also evaluated. The conditions of preparation of the starch derivatives were optimized and presented in multi-regression equations. Properties of the final composites using the new system were determined, including static bending, internal bond strength and water resistance. The ageing behavior of the new composites was also evaluated and compared to the urea-formaldehyde system without the added starch derivatives.