Effect of plasma treatment on the AAc grafting percentage of high-density polyethylene

Argon (Ar) plasma pretreated high-density polyethylene (PHDPE) was grafted with acrylic acid (AAc-g-PHDPE) using benzoyl peroxide (BPO) as an initiator and alcohol as a solvent. Effects of plasma treatment time, plasma power, and storage time on CO/CO ratio of PHDPE were studied. Effects of initiator concentration and reaction time on percent grafting were also studied. In this study, the authors used electron spectroscopy for chemical analysis (XPS) to measure the maximum CO/CO ratio of PHDPE, except that the maximum peroxide concentration of PHDPE was measured by 1,1-diphenyl-2-picryhydrazyl measurement method. Furthermore, the PHDPE was susceptible to further surface modification by thermal-induced graft copolymerization with a vinyl monomer, such as AAc and used BPO as initiator. The grafting percentage of AAc-g-PHDPE was from 10% without BPO initiator to 25% with BPO 1×10−4 M. The plasma power and plasma treatment time affected not only the surface composition of treated film but also the grafting percentage. As AAc was grafting in alcohol solution, the carboxylic acid will be formed and an overlapped carboxylate ion.