Microgels versus linear polymers for paper wet strength - Size does matter

Polyvinylamine (PVAm) microgels (∼1.5 μm diameter) were compared with the corresponding linear polymer (∼40 nm) as wet strength resins for paper. Handsheet studies showed that microgels gave substantially higher wet tensile strength than the same dosage of linear polymer. By contrast, impregnation of filter paper with polymer or gel solution gave the opposite effects - wet paper impregnated with linear polymer was stronger than the microgel …