Synthesis of polymers containing isocyanate groups and use of polymers as paper dry and wet strength additives

Abstract

Results of the preparation and characterization of homopolymers of 2-methacryloyloxyethyl isocyanate (MOI) and co-polymers of MOI with styrene synthesized by radical polymerization are shown. The polymers were significantly effective as additives for paper dry and wet strength. Dry strength can be increased by 75% and wet strength retention of sheets can reach 30% based on the increased dry strength and about 50% based on the dry strength of untreated sheet. In terms of sheet wet strength improvement, based on isocyanate group consumption, copolymers containing less isocyanate obtain a better effect than homopolymers. Furthermore, base paper containing a small amount of polyallylamine hydrochloride was used for polymer treatment and produced more wet strength improvement.