Sizing performance of alkenyl succinic anhydride (ASA) emulsion stabilized by polyvinylamine macromolecules

It is well known that alkenyl succinic anhydride (ASA), an alkaline sizing agent, when applied to cellulosic fibers will impart a resistance to the absorption of water. High reactivity of ASA to cellulosic fiber compared to that of alkyl ketene dimer (AKD) is the main advantage of ASA sizing. However, there are some drawbacks associated with the ASA sizing viz. poor stability of ASA emulsion and formation of stickies and deposits as a result of hydrolyzed ASA. Present study deals with the stability of ASA emulsions prepared by using synthetic vinylamine polymers of different colloidal charge as alternate to conventionally used cationic starch and sizing performance using mixed hardwood kraft pulp furnish. The better colloidal stability and sizing performance with polyvinylamines compared to cationic starch was due to the coverage of the ASA droplets with polyvinylamines which extends in to the continuous phase of ASA emulsion. Emulsion stability was achieved even with low dosage of vinylamine polymer.