Microstructure and performance of block copolymer modified epoxy coatings

The effects of two diblock copolymers, poly(ethylene-alt-propylene)-b-poly(ethylene oxide) (PEP PEO) and poly(1,2-butadiene)-b-poly(2-vinyl pyridine) (PB P2VP) on the mechanical properties of epoxy coatings were studied. Both modifiers self-assembled into spherical micelles of 10-20nm diameter in cured bulk epoxy. This morphology was preserved in 15 mu m thick coatings; however, micelle segregation to the coating/substrate interface was also observed. The critical strain energy release rate, G(1C), of bulk thermosets was enhanced by up to fivefold with the addition of block copolymers. Likewise, the abrasive wear resistance of thin coatings increased with modifier inclusion. The results showed that at 5 wt.% of loading, block copolymers were able to impart a 40% increase in abrasive wear resistance to modified coatings over neat ones. Block copolymer modifiers did not sacrifice the modulus and glass transition temperature of bulk thermosets and coatings, or the hardness and transparency of coatings, or the hardness and transparency of coatings. (C) 2014 Elsevier B.V. All rights reserved.