Syntheses of PVA/starch grafted hydrogels by irradiation

A series of excellent polyvinyl alcohol (PVA)/starch blend hydrogels were prepared by gamma and electron beam radiation at room temperature. The influence of dose, the content of starch in blend systems on the properties of the prepared hydrogels was investigated. The gel strength was improved obviously after adding starch into PVA hydrogels, but the swelling properties decreased slightly due to poor hydrophilicity of starch. In order to elucidate the effect of component of starch on the properties of PVA/starch hydrogels as well as the formation mechanism of PVA/starch blend hydrogels under irradiation, the two components of starch, amylose and amylopectin, were chosen to blend with PVA to prepare the hydrogels, respectively. The results indicated that the amylose of starch was a key component that influenced the properties of PVA/starch blend hydrogels. The further analyses of FTIR, DSC and TGA spectra of the prepared gels after extracting sol manifested that there was a grafting reaction between PVA and starch molecules besides the crosslinking of PVA molecules under irradiation, and the amylose of starch was a key reactive component.