Benzylated waste pulps (PBzs) were synthesized from treated waste pulp (Pulp), and benzyl chloride with phase transfer catalyst (PTC), and graft copolymers (PBz-g-LA) were synthesized from PBzs and L-lactic acid (LA). Thermal properties, solubility, crystallinity, and biodegradability of the obtained PBzs and graft copolymers were investigated. PBzs with the degree of substitution (DS) higher than 1.5 showed T-g and T-m in DSC measurement. All PBz-g-LA exhibited no T-m. However, the graft copolymers obtained from lower DS PBzs having no T-g, exhibited T-g. The solubility of PBzs enhanced with increasing DS, and the crystallinity of PBzs reduced with increasing DS because of hydrophobicity and steric effect of benzyl groups. The solubility of graft copolymers was similar to that of original PBzs. Biodegradation tests for PBzs, Pulp, and graft copolymers were performed using cellulase in 0.1 M acetate buffer solution (pH 5.5) at 37 degreesC. All samples showed biodegradability though the biodegradation rate decreased with increasing DS of PBz. In PBz-g-LA, the initial biodegradation rate was faster than that of original PBz because of hydrolysis of LA units. (C) 2004 Wiley Periodicals, Inc.