SynopsisThe scope of graft reactions to produce starch-based latexes was extended by graft polymerization of acrylonitrile (AN) onto gelatinized cationic starch possessing quaternary amine functionality and by graft terpolymerization of AN and t-butylaminoethyl methacrylate (TBAEM) onto gelatinized starch by cerium(1V) initiation a t 25OC. Grafting onto starches containing highly basic quaternary amines gave polyacrylonitrile [poly(AN)] grafts having about one fourth the number-average molecular weight (Hn) (178,000-232,000) of those produced by grafting AN onto starches containing the less basic tertiary m i n e groups. Sonification a t 20 KHz of graft polymerization reaction mixtures having up to 8% solids reduced viscosities from 400-3000 cP to 10-40 cP. Diameters of dried particles measured about 300-1500 A. Shaker-type agitation during grafting onto starch having quaternary amine groups produced poly(AN) chains with lower A?,, values than those produced during blade stirrer-type agitation. M,, values of grafted poly(AN) decreased with increasing reaction time, degree of substitution of amine in the starch, gelation time of cationic starch a t 95OC, and cerium(1V) concentration. AN was copolymerized with TBAEM at molar ratios of 14-85:l in grafting onto gelatinized starch to yield copolymer side-chain grafts analyzing 8-52:l of polymerized AN to TBAEM moieties.

Starch‐polyacrylonitrile (S‐PAN) graft copolymer consisting of one part starch and one part polyacrylonitrile (M. W. 794,000) was hydrolyzed with aqueous KOH at 80 and 100°C to polyelectrolytes containing carboxyl and amide functionality but void of infrared‐detectable amounts of nitrile. Viscosities of potassium salts of the polyelectrolytes in water were pH dependent with peak viscosities at 8.5. These dispersions were characterized by unusually high viscosities, 15,000 to 26,500 cp at 1% concentration, and by the ability to retain significant viscosities, 300 to 950 cp, upon dilution to 0.03% concentrations. A 1% dispersion of hydrolyzed S‐PAN had a viscosity of 5,000 cp in the presence of 8% KCl; however, the depressing effect of added salts on viscosity of aqueous dispersions of hydrolyzed S‐PAN increases as the valence of the cation increases.

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