Recyclable, self-healing itaconic acid-based polyurethane networks with dynamic boronic ester bonds for recoverable adhesion application

Abstract

Currently, synthesis of biobased polyurethane (PU) networks with recyclability, self-healing, as well as robust mechanical and adhesion properties still remain a challenge. Herein, a series of robust itaconic acid-based polyurethane networks (IAPU) with dynamic boronic ester bonds are fabricated and fully characterized by FTIR and DMA. All the obtained IAPU networks display high thermostability with an initial decomposition temperature around ∼270 °C. The activation energy and typology transition temperature of the IAPU-80 are 71.9 kJ mol−1 and -25.8 °C, respectively. The IAPU-80 shows low relaxation times from 169 to 125 s at moderate temperature from 60 to 65 °C, respectively, as well as excellent mechanical properties (tensile strength = 15.6 MPa, elongation at break = 70.4%, toughness = 12.6 MJ m−3). The IAPU-80 possess outstanding scratch self-healing ability (scratch disappear after heating at 120 °C for 10 min) and reprocessability (without distinct decrement of the tensile strength after twice recycling). Remarkably, the IAPU-80 bonded wood sample exhibits a high recoverable adhesion strength (∼8.2 MPa), after reused for three times. Therefore, the self-healing and malleable IAPUs with recoverable adhesion performance are obtained by incorporating dynamic boronic ester bonds into itaconic acid-based polyurethane networks. Present work describes a green and facile way to prepare sustainable PU networks with multiple functionalities for wide applications.