Synthesis and Characterization of Homogeneous Epoxy Networks: Development of a Sustainable Material Platform Using Epoxy-Alcohol Polyaddition

Abstract

The development of bio-based epoxy resins from aliphatic biomass and lignin has rapidly increased over the past few decades. While thermal curing of such monomers with polyfunctional amines and anhydrides has been intensively discussed in literature, surprisingly, their polymerization behavior using alcohols as co-curing agents and the resulting mechanical properties have not been investigated in detail up to now. Herein, the polymerization mode of bio-based epoxides with alcohols using imidazoles as catalysts was studied via1H-NMR analysis, revealing a controlled alternating co-polymerization between difunctional epoxy and alcohol monomers. Furthermore, differential scanning calorimetry analysis was used to obtain the theoretical heat of polymerization (∼100 kJ mol−1) of multifunctional monomers and the formulations exhibited high storage stabilities of up to 28 days. By varying the core structure and functionality of the epoxy monomers, high-performance thermosets with a tunable TG (0−110 °C) and high tensile toughness of up to 18 MJ m−3 were obtained. These performances show potential for the application of bio-based epoxy networks as coatings for key industrial sections such as automotive technologies.