Chemically recyclable glycerol-biobased polyether thermosets

Abstract

Glycerol is a chemical byproduct of biodiesel synthesis that has become an important raw material for use in the food, personal care and pharmaceutical industries. However, even with these applications, there is an imbalance between the growing production of glycerol and the demand for it. In this work we propose the use of glycerol and diglycerol as raw materials for the synthesis of fully recyclable aliphatic polyether thermosets. Fully biobased polyether thermosets are prepared by the acid-catalyzed bulk self-condensation of glycerol and diglycerol with different ratios of 1,6-hexanediol at 170 °C using an acid-base non-eutectic mixture organocatalyst (NEMO). The thermosets are characterized using solid-state 13C NMR, FTIR, DMA and DSC. The mechanical properties of the thermosets can be varied by adjusting the glycerol to diol ratio, leading to rigid or flexible thermoset films with varying Young’s modulus and elongation at break. Finally, we also demonstrate that the glycerol and diglycerol based thermosets can be depolymerized back to the initial monomers by hydrolysis under acidic conditions and subsequently repolymerized to obtain chemically recyclable biobased thermosets.