Functionalization of Poly[Ethylene Terephthalate) by Means of Glow-Discharge-Initiated Polymerization of Acrylic Acid

Glow-discharge-initiated polymerization of acrylic acid incorporated in poly(ethylene terephthalate) (PET) films was investigated. An increase in polymerization yield with plasma treatment duration and power was found. Polymerization was not confined to the film surface. At high power and long treatment time, polymerization in the bulk of the PET also took place. Water regain and contact angle of the PET-treated films were affected by the presence of poly(acrylic acid) (PAA). The carboxyl groups of the PAA chains incorporated in the PET matrix were utilized for further chemical modification of the PET film. Poly(ethylene glycol) (PEG) was grafted onto PAA by esterification. DSC studies showed the presence of both PAA and PEG in the PET matrix and shed light on the morphology of the multicomponent polymeric system. Free isocyanate groups were introduced into the PET matrix by reacting PAA carboxyl groups with hexamethylene diisocyanate.