Bona fide upcycling strategy of anhydride cured epoxy and reutilization of decomposed dual monomers into multipurpose applications

Abstract

Waste epoxy materials become an enormous problem to society and the environment. The advantages of epoxy resins derive from their rigid and chemically stable networks, but these qualities also make them difficult to dispose of or recycle. Herein, we demonstrated an efficient degradation of anhydride cured epoxy resin by aminolysis in aminoethanol without using any catalysts. The epoxy resin was fully decomposed at 160 °C in 4 h, resulting in two distinct high purity monomers (HHPA-OH and BPA-OH). To fully realize this upcycling approach, The BPA-OH was used to synthesize a polyurethane coating with an excellent glass transition temperature (88.9 °C), scratch hardness (8H), gouge hardness (6H), adhesive strength (5B), and strong solvent resistance. The HHPA-OH with two hydroxyl groups was reacted with methacrylic anhydride to form a dimethacrylate monomer which was then used as a viable crosslinker for photo-curable 3D printing thermosetting polymer with tensile strength as high as 64 MPa and impact strength of 4.86 kJ/m2. This work demonstrates a feasible pathway to convert anhydride cured epoxy waste to new monomeric recyclates for superior polymer products.