Preparation and properties of castor oil-based photothermal dual-responsive DCPNs containing azophenyl groups

Abstract

A novel castor oil-based reactive monomer containing carboxyl and azobenzene groups named ECODABMNA was prepared. Then, a series of dynamic covalent polymer networks (DCPNs) containing photothermal responsive groups with good mechanical properties were designed and fabricated by curing different epoxy resins (E51, E44 and EBA30) with ECODABMNA as the curing agent. The successful fabrication of the epoxy networks was demonstrated by Fourier transform infrared spectrometry and ¹H nuclear magnetic resonance spectroscopy. The thermal stability and thermomechanical, self-healing, and photothermal shape memory properties were investigated. The epoxy network prepared from E51 had superior thermal stability, the highest initial thermal decomposition temperature of above 280 °C, and the highest glass transition temperature of 72.04 °C. All castor oil-based DCPNs exhibit good thermal stability with a minimal weight loss of below 200 °C. Mechanical property tests showed that the DCPNs can achieve a tensile strength of 13.06 MPa and an elongation at break of 94.38% simultaneously. The DCPNs exhibit not only excellent photothermal shape memory properties, but also certain self-healing functions.