Preparation of gallic acid modified waterborne polyurethane made from bio-based polyol

WPU was prepared by a simple and bio-based method using poly(1,3-propylene glycol-adipic acid) (PPA) and isophorone diisocyanate (IPDI) as raw materials. Intriguingly, PPA can be synthesized using 1,3-propanediol which was extracted from plant stalk. Then a non-toxic, environmental-friendly gallic acid modified bio-based waterborne polyurethane (GWPU) was successfully prepared utilizing the prepolymer method with gallic acid (GA) was as a modifier. The structures, morphologies and thermostability of GWPU were confirmed by FTIR, TEM, TG , DSC and AFM . Furthermore. Its mechanical properties and water resistance were evaluated as well. The results demonstrated that self-prepared PPA has no influence on the properties of polyurethane. However, when the content of GA was increased from 0% to 3.3%, the tensile strength of GWPU film increased by 155.3% compared with that of unmodified PU film, the elongation at break decreased by 86%, and the decomposition temperature of the film increased by 23.8 °C, the surface roughness decreased by 41.0%. In addition, through the crosslinking of GA, the water resistance of GWPU is improved.