Exploiting β-amino ester chemistry to obtain methacrylate-based covalent adaptable networks

Abstract

In this study, β-amino ester-based covalent adaptable networks (CANs) were synthesised through aza-Michael addition of amines to methacrylates, with the aim of developing industrial products. Typically, CANs based on β-amino esters employ acrylate moieties, which are known to be toxic and hazardous to human health and the environment. Therefore, methacrylate-based networks were explored as a safer alternative to the chemistry currently in use. Network formation was monitored by following the evolution of the glass transition temperature over time and conducting soluble fraction tests. Subsequently, industrial methacrylic monomers were employed to develop an industrially relevant material, utilizing previously established curing conditions for methacrylate systems. The dynamic behaviour of the network was assessed through rheological characterisation. The material demonstrated the ability to relax applied stress at various temperatures displaying typical viscoelastic fluid behaviour, indicative of exchangeable linkages within the macromolecular architecture. Shape memory and reprocessing capability were successfully tested under appropriate thermo-mechanical stimulation. Both thermal analyses and FT-IR spectra confirmed the retention of chemical composition and material properties throughout recycling process.