Designing Cure Kinetics in Polyester Networks: Tuning Initiator Content to Control Gelation and Glass-Transition Development
Year: 2026
Type: preprint
Abstract: Unsaturated polyester networks remain widely used in composite manufacturing, construction, and infrastructure, and yet the practical relationship between initiator content and cure trajectory is not always reported consistently across industrial formulations. Using a field-representative unsaturated polyester systems, real-time gelation/exotherm were tracked with differential scanning calorimetry (DSC) to map how initiator type and content govern gel time, exotherm behavior, and the thermal state of the cured network. Across the compositions examined, gel time varied roughly four-fold, from approximately 10–12 minutes to 44–45 minutes, and peak exotherm temperature reached approximately 123–137 °C. Across an extended 0.8–4% peroxide range, the first-scan glass transition (Tg1) rose from 46.15 to 56.38 °C and residual cure enthalpy (ΔH) fell from 33.35 to 15.67 J/g, while the fully cured glass transition (Tg2) rose sharply to approximately 100–103 °C at intermediate peroxide content before declining to 84.74–89.20 °C at 3–4%. These results indicate that additional initiator can accelerate cure and reduce measured residual reaction while not necessarily improving the final thermal state of the network.
Source: ChemRxiv
Author: Parastou Kharazmi
Institution: KTH Royal Institute of Technology
Language: English
Topic: Epoxy Resin Curing Processes
Subfield: Polymers and Plastics
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7213886728