Bio‐based high‐performance waterborne hyperbranched polyurethane thermoset

Abstract

Tannic‐acid‐based low volatile organic compound‐containing waterborne hyperbranched polyurethane was prepared. In order to improve the performance, it was modified in an aqueous medium using a glycerol‐based hyperbranched epoxy and vegetable‐oil‐based poly(amido amine) at different wt%. The combined system was cross‐linked by heating at 100°C for 45 min. Fourier transform infrared spectroscopy and swelling study were used to confirm the curing. A dose‐dependent improvement of properties was witnessed for the thermoset. Thermoset with 30 wt% epoxy showed excellent improvements in mechanical properties like tensile strength (~3.4 fold), scratch hardness (~2 fold), impact resistance (~1.3 fold), and toughness (~1.7 fold). Thermogravimetric analysis revealed enhancement of thermal properties (maximum 70°C increment of degradation temperature and 8°C increment of Tg). The modified system showed better chemical and water resistance compared with the neat polyurethane. Biodegradation study was carried out by broth culture method using Pseudomonas aeruginosa as the test organism. An adequate biodegradation was witnessed, as evidenced by weight loss profile, bacterial growth curve, and scanning electron microscope images. The work showed the way to develop environmentally benign waterborne polyurethane as a high‐performance material by incorporating a reactive modifier into the polymer network. Use of benign solvent and bio‐based materials as well as profound biodegradability justified eco‐friendliness and sustainability of the modified system. Copyright © 2015 John Wiley & Sons, Ltd.