Amylography and scanning electron microscopy (SEM) studies on grafted copolymers of starch with methacrylic acid and methyl methacrylate demonstrated significant changes in the viscosity and granule disintegration characteristics, depending on the extent of grafting and the nature of the monomer. Marked viscosity changes were observed when the carboxyl groups of the starch-graft-poly(methacrylic acid) (SPMAA) were neutralized with sodium hydroxide. The viscosity modification was found to be dependent on the extent of neutralization, and a maximum was observed at 10-25% neutralization. With an increase in extent of neutralization, there was a decrease in gelatinization temperature. For a sample of SPMAA with a percentage grafting of 14.1, the gelatinization temperature decreased from 64degreesC for the acid form to 42degreesC for the fully neutralized form. The gelatinization temperature of the fully neutralized samples of SPMAA showed a linear relationship with the percentage grafting. SEM was used to elucidate the effect of grafting on the granule swelling characteristics of starch at various temperatures. In the case of starch-graft-polymethyl methacrylate (SPMMA), granule disruption on heating with water was observed. However, this did not lead to the build-up of viscosity on gelatinization. This was explained to be caused by the hydrophobic nature of SPMMA.