Waterborne hyperbranched poly(ester amide urethane) thermoset: Mechanical, thermal and biodegradation behaviors

Abstract

Renewable resource based waterborne hyperbranched poly(ester amide urethane)s (WHPEAU) with varying compositions were synthesized by reacting polyamide polyol of diethanol amine, caprolactam and citric acid with dimer acid, phthalic anhydride and isophorone diisocyanate via a catalyst and solvent free facile route. The parent poly(ester amide) was obtained by using the same technique and reactants except isophorone isocyanate. The chemical structures of the prepared polymers were characterized by NMR and FTIR spectral analyses. The thermosets of these polymers were obtained by chemical crosslinking with commercially available epoxy and fatty acid modified poly(amido amine) hardener. These thermosets showed high mechanical properties like tensile strength (7.5 MPa against 3 MPa) and toughness (14.48 MJm−3 against 6 MJm−3) without much losing the elongation at break (174% against 286%) over the poly(ester amide) thermoset. Further, chemical resistance of the thermosets in different chemical media was found to be better than the poly(ester amide) thermoset. Most interestingly, the accelerated bacterial biodegradability using bacterial strain like Pseudomonas Auregonisa (P. Auregonisa) revealed almost comparable biodegradability to the poly(ester amide) thermoset. The WHPEAU thermosets, thus, not only exhibited high performance but they also possess required attributes to be used as environmentally benign polymeric material.