Constructing Phenyl Propargyl Ether-Functionalized Biobased Epoxy Resins with Outstanding Heat Resistance for Triboelectric Nanogenerators under Extreme Conditions

Triboelectric nanogenerators (TENGs) hold great promise as a novel clean energy source, yet the poor heat resistance of existing polymer triboelectric layers restricts their application in extreme environments, while their petrochemical origins also raise sustainability concerns. Herein, two biobased epoxy monomers (OMPB and OBPB) with varying propargyl ether functionalities were designed and synthesized from lignin derivatives and combined with the liquid curing agent methyl nadic anhydride (MNA) to form biobased epoxy resin systems with good processability and high heat resistance. Specifically, the cured OBPB/MNA resin exhibits a remarkable glass transition temperature (Tg) of 375 °C, which is 180 °C higher than that of the commercial DGEBA resin and represents the highest values among reported lignin-derived epoxy resins. Additionally, it maintains a storage modulus of 1.46 GPa at 350 °C, indicating its potential for high-temperature applications. By systematically investigating the structure–property relationships, the mechanism underlying this high performance was revealed. Benefiting from the exceptional processability, an OM-TENG was fabricated via integrated molding using OBPB/MNA resin as the triboelectric layer, and it exhibited stable electrical output even at 315 °C. This research provides a new class of high-performance, processable epoxy resins, facilitating the scalable fabrication of TENGs for extreme-environment applications.