Synthesis and characterization of photo-crosslinkable linear segmented polyurethanes based on coumarin

Abstract

Linear segmented polyurethanes with 10% weight of coumarin groups within the soft segment, the hard segment or equally distributed between both segments were successfully prepared. These polyurethanes, based on polycaprolactones, isophorone diisocyanate, butanediol and a dihydroxylated coumarin monomer, were completely amorphous and homogeneous with a single phase morphology. In non-irradiated polyurethanes Tg value varied linearly with hard segment content that in turn was the main factor influencing the mechanical properties. Photodimerization at 354 nm produced crosslinked materials with little change on the Tg and outstanding mechanical properties, as high as 54 MPa, better than that of any other coumarincontaining polymer described.