GRAFTING ACRYLIC ACID TO STARCH BY PREIRRADIATION.

The grafting of acrylic acid (AAc) to starch was investigated with gamma-pre-irradiated starch and aqueous solutions of AAc. The rate of grafting increased initially with time, then decreased, and approached zero when the percentage grafting reached a maximum value. At a given radiation dose the rate of grafting was proportional to the first power of the concentration of irradiated starch and to the 1.5 power of the initial concentration of AAc. Solvent effects on degree of grafting, molecular weight, and number of grafted branches were evaluated. Higher degrees of grafting were achieved with electron-irradiated starch at radiation doses lower than those used with gamma rays.