Curing Kinetics and Process Optimization of Epoxy Vitrimer Insulation Composites Enabled by a Novel Latent Catalyst

Epoxy vitrimers with dynamic covalent bonds enable the recovery and reuse of epoxy resin in dry-type transformers. However, common transesterification catalysts like 1,5,7-triazabicyclo [4.4.0]dec-5-ene (TBD) severely narrow the processing window. To reconcile recyclability and processability, Ji and coworkers develop a novel thermally latent catalyst, PH-TBD. This study systematically investigates the processing window, curing behavior, and process optimization of PH-TBD-catalyzed epoxy vitrimers and composite insulation materials. Rheological analysis quantifies how catalyst loading regulates viscosity, confirming that PH-TBD effectively broadens the casting window. DSC studies analyze the effects of catalysts and fillers on curing kinetics. A curing-heat transfer coupling model is established via numerical simulation to accurately simulate the temperature field and curing degree evolution during the curing of high-filled composites, yielding an optimized step-curing process. Results demonstrate that adjusting curing temperature and time enables uniform network construction and performance optimization. Consequently, an optimized curing process of 110 °C/3 h + 120 °C/3 h + 140 °C/4 h is established, providing critical technical support for the controllable preparation of high-performance, recyclable epoxy composite insulation materials.