Cationic and Nonionic Starch Graft Polymers for Filler Retention

Graft co‐ and terpolymers were prepared by free radical polymerizations of vinyl monomers onto ω‐irradiated starch by a prototype commercial process. Products with graft contents of up to 46%, by weight, were obtained by grafting acrylamide and quaternary amine‐containing esters of methacrylic acid to starch. The graft polymers were evaluated on a pilot fourdrinier paper machine as filler retention aids and compared with several commercial flocculants. Drainage rate increased markedly with one of the starch graft terpolymers that was cationic. Since the number of starch graft polymers prepared was limited, the results reported, although excellent, are not necessarily optimal. Further studies are needed to establish the relationships of graft content and terpolymer compositions to retention and drainage.