Effect of polymer composition on performance properties of maleate-vinyl ether donor-acceptor UV-curable systems

The effect of unsaturated polyester backbone composition on the properties of donor-acceptor-UV-cured coatings was explored. The polyesters were designed with similar molecular weights and levels of unsaturation, but with otherwise widely varying backbone compositions. UV-curable coatings were formulated with stoichiometric levels of triethylenglycol divinyl ether and a photoinitiator. The resulting coatings had a broad range of properties, which were found to correlate with the properties and compositions of the polyester backbone polymers. A relatively flexible backbone resulted in lower glass transition temperatures (T_g). The polymer T_g was found to influence the conversion of double bonds achieved during UV curing. Reaction kinetics were evaluated for the coating systems and the results confirmed that the T_g of the systems influenced the double bond conversion. Thermal stability and König pendulum hardness were also found to vary with the backbone composition of the constituent polyester.