The effect of hot DMSO treatment on the γ-ray-induced grafting of acrylamide onto PET films

Abstract

In the present study, the γ-ray induced grafting of acrylamide (AAm) onto poly(ethylene terephthalate) (PET) films and the resulting changes in properties, including the Hg(II)-capturing functionality, were investigated. No grafting was observed on pristine PET films. Therefore, the films were treated with dimethyl sulfoxide (DMSO) before the γ-ray grafting with the goal of facilitating grafting; some of the samples were pretreated at high temperature (100–160 °C) and showed a considerable increase in the adsorption of AAm from solution. The highest graft yield obtained in the present study was 15.5% for the DMSO specimens pretreated at 140 °C and γ-ray irradiated with a 100-kGy total dose (1-kGy h−1 dose rate) in 50 wt% AAm-monomer solutions in the presence of 1 wt% FeCl3 (polymerization inhibitor). In addition to the promotion of the graft yield, the formation of micropores in the DMSO-pretreated specimens was found during the optical microscopy investigations. This structural change is hypothesized to assist the adsorption and γ-ray grafting of AAm to PET. The AAm-grafted PET films prepared using DMSO pretreatment showed high removal efficiency for Hg(II) ions, whereas the pristine PET film showed no uptake, reflecting these changes. It was found that the γ-ray-induced grafting of AAm on PET film is considerably facilitated by hot DMSO pretreatment. The DMSO pretreated PET films exhibit noticeable surface morphological changes including micropore creation, which is hypothesized to promote the AAm grafting.