Synthesis of low cost adhesives from pulp & paper industry waste

This study presents lignin extraction from commercial black liquor and utilizes it as a partial substitute in phenol formaldehyde (PF) resin synthesis. Characteristics of modified resin [non volatile solid content (< 44%), alkalinity (< 5%), pH (< 11.6) and free formaldehyde (< 1%)] were found close to control PF resin with a variable viscosity (418-781 cP). Shear test properties showed that phenol (15%) replacement with black liquor lignin produced comparable physical bond properties and could be used to formulate a low cost modified PF resin for plywood panels.