UV curable, flame retardant, and pressure-sensitive adhesives with two-way shape memory effect

Abstract

Novel UV curable acrylic pressure-sensitive adhesives (PSAs) with exceptional flame retardancy and promising two-way shape memory effect have been developed using a commercial diethyl phosphoramidate as multifunctional tackifier for the first time. The abundant hydrogen bonds and high viscosity of the resultant networks contribute to the low temperature and repeatable adhesions. The PSA with 5 wt % tackifier exhibited the best overall adhesion at both 25 °C and 0 °C, especially with the relatively high peak adhesive stress and the highest work of adhesion. Owing to the synergistic effect with nitrogen containing acylate monomer, the 15 wt% diethyl phosphoramidate endowed the PSA sample with self-extinguishing ability. Moreover, the higher viscoelasticity makes the tackified PSAs with better two-way shape memory property. In particular, the elongation upon cooling and contraction upon heating are 57.2% and 55.9%, respectively. • A multifunctional tackifier for acrylic pressure-sensitive adhesives is reported. • The PSAs integrate UV curability, flame retardancy, and two-way shape memory effect. • A condensed phase flame retardant mechanism of phosphoramidate is proposed. • The higher viscoelasticity suggests better two-way shape memory property. • Two-way shape memory effect in cyclic freezing and thawing scenario is demonstrated.