Studies on Diels-Alder thermoresponsive networks based on ether-urethane bismaleimide functionalized poly(vinyl alcohol)

Thermoreversible networks obtained by the Diels-Alder cycloaddition reaction of poly(vinyl furfural) with urethane bismaleimides containing polyether chain were synthesized. The formation of the networks was confirmed by attenuated total reflectance in conjunction with Fourier transform infrared spectroscopy (ATR-FTIR). The materials thermal properties were investigated using differential scanning calorimetry (DSC) and a coupling of dynamic thermogravimetry with Fourier transform infrared spectroscopy and mass spectrometry (TG-FTIR-MS) for pyrolysis behaviour under nitrogen atmosphere. A thermal decomposition mechanism of the networks and poly(vinyl furfural) was discussed via evolved gas analysis. The thermoreversibility of the networks was demonstrated by the presence of the endothermic peak characteristic to the retrodienic process on the DSC heating curves and also the appearance of the exothermic peak, due to the dienic process, on the DSC cooling curve. The dynamic contact angle and free surface energy values of the networks were determined. Measures of the heterogeneity and roughness of the surfaces suggested that the surfaces of the networks' films are more homogenous than the initial poly(vinyl furfural) surface. Dynamic water vapour sorption studies were conducted.