Tannic Acid-Based Polycarbonate Networks: A Sustainable Material with High Mechanical Strength, Flame Retardancy, Reprocessability, and Photothermal Self-Healing Properties

Abstract

Polycarbonate (PC) vitrimers can be reprocessed without sacrificing their mechanical properties. However, the usage of petroleum-based raw materials for their preparation makes the process unsustainable. Herein, for the first time, sustainable tannic acid (TA)-based PC vitrimers with integrated high mechanical strength, flame retardancy, reprocessability, and photothermal self-healing capabilities were synthesized via a facile one-step reaction between bio-based TA and bis(6-membered cyclic carbonate) (BCC). The TA content significantly influences the network properties: increasing TA enhanced crosslinking density, leading to superior tensile strength (68.8 MPa), Young’s modulus (2153 MPa), and flame retardancy (UL-94 V-0 rating, LOI 30.0%). Dynamic transcarbonation bonds enabled efficient stress relaxation and reprocessability. Notably, the TA-based PC network exhibited exceptional photothermal conversion efficiency (86.5%), enabling rapid scratch healing (96.9% recovery under NIR irradiation). This work provides a sustainable strategy to replace petroleum-based PC network with biomass alternatives, addressing recyclability and fire safety challenges while maintaining high performance.

Keywords: tannic acid, Polycarbonate vitrimers, Fame retardancy, Photothermal self-healability, Mechanical strength