Acrylic ABA triblock copolymer bearing pendant reactive bicycloalkenyl functionality via ATRP and tuning its properties using thiol-ene chemistry

This investigation reports the preparation of tailor-made ABA triblock copolymers (BCP) of 2-ethylhexyl acrylate (PEHA) and dicyclopentenyloxyethyl methacrylate (PDCPMA) bearing pendant reactive cycloalkenyl functionality via atom transfer radical polymerization (ATRP) and thiol-ene modification of the pendant reactive bicycloalkenyl functionality. The chemical structure and molar composition of the polymers were determined by 1H NMR spectroscopy and molecular weights of the polymers were determined by gel permeation chromatography. AFM as well as DSC analysis showed nanophase-separated morphology in the block copolymers. The pendant reactive bicycloalkenyl group of PDCPMA in the BCPs was successfully modified by thiol-ene reaction and the mechanical properties of the modified BCPs were studied. The thiol modified BCP showed much greater adhesion strength compared to pristine BCP as determined by lap shear test using a UTM. Hardness of the BCP film and UV-cured thiolated BCP film was studied and compared by using a nanoindenter.