Surface properties of modified acrylates

Surface evaluation has been used to follow modification progress when acrylic copolymers were reacted with ethylenediamine. Among studied materials copolymer of trimethylolopropane triacrylates (TMPA), butyl acrylate (BA) and vinyl acetate (VA) was the most susceptible to aminolysis. Evaluation of surface polarity showed that modification was completed after 150 s. However, surface titration, e.g. registration of contact angle for aqueous solutions of HCl and NaOH with pH ranging from 2 to 12, indicated appearance of acidic and basic groups on modified surface. Moreover, surface basic groups were slowly replaced by carboxylic functionalities when the modification time was increased. The paper shows the usefulness of contact angle evaluation to monitor of polymer modification process.