Biodegradable Hyperbranched Epoxy from Castor Oil-Based Hyperbranched Polyester Polyol

Abstract

An outstanding tough, highly elastic, biodegradable, and thermostable hyperbranched epoxy was synthesized by a simple polycondensation reaction between a castor oil-based hyperbranched polyester polyol (HBPP) of monoglyceride of oil and bis(hydroxy methyl)propionic acid (Bis-MPA) and in situ-generated diglycidal ether of bisphenol A (DGEBA). The structure of HBPP was confirmed from FTIR, NMR, and different analytical studies. The formation of hyperbranched epoxy along with its structure was analyzed by different spectroscopic and analytical techniques. The poly(amido amine)-cured hyperbranched epoxy exhibited high tensile strength (42 MPa), extensibility (88% elongation), toughness (3144), scratch hardness (>10.0 kg), impact resistance (>100 cm), flexibility (bent up to 180° without damage), and biodegradation. The results indicate the strong influence of the amount of polyester polyol and bisphenol A on the performance of the thermosets. The study showed the superiority of the studied hyperbranched epoxy over the standard commercial bisphenol A-based epoxy (SBE) as well as the physically modified SBE with 10 wt % of HBPP. This biodegradable, elastic, and tough epoxy thermoset can be used as a sustainable advanced material.