Plasma-induced craft polymerization of acrylic acid onto poly(ethylene terephthalate) films

The graft polymerization of acrylic acid was carried out onto poly(ethylene terephthalate) films that had been pretreated with argon plasma and subseq uently exposed to oxygen to create peroxides. The influence of synthesis co nditions, such as plasma treatment time, plasma power, monomer concentratio n, temperature, and the presence of Mohr's salt, on the degree of grafting was investigated. The observed initial increase in grafting with monomer co ncentration accelerated at about 20% monomer. The grafting reached a maximu m at 40% monomer and subsequently decreased with further increases in monom er concentration. The reaction temperature had a pronounced effect on the d egree of grafting. The initial rate of grafting increased with increasing t emperature, but the degree of grafting showed a maximum at 50 degreesC. The activation energy of the grafting obtained from an Arrhenius plot was 29.1 kJ/mol. The addition of Mohr's salt to the reaction medium not only led to a homopolymer-free grafting reaction but also diminished the degree of gra fting. The degree of grafting increased with increasing plasma power and pl asma treatment time. (C) 2001 John Wiley & Sons, Inc.