Development of a Cure Model for Unsaturated Polyester Resin Systems Based on Processing Conditions

Polymers (Basel). 2024 Aug 23;16(17):2391. doi: 10.3390/polym16172391.

Abstract

Unsaturated polyester resin (UPR) systems are extensively used in composite materials for applications in the transportation, marine, and infrastructure sectors. There are continually evolving formulations of UPRs that need to be evaluated and optimized for processing. Differential Scanning Calorimetry (DSC) provides valuable insight into the non-isothermal and isothermal behavior of UPRs within a prescribed temperature range. In the present work, non-isothermal DSC tests were carried out between temperatures of 0.0 °C and 250 °C, through different heating and cooling ramp rates. The isothermal DSC tests were carried out between 0.0 and 170 °C. The instantaneous rate of cure of the tested temperatures were measured. The application of an autocatalytic model in a calculator was used to simulate curing behaviors under different processing conditions. As the temperature increased from 10 °C up to 170 °C, the rate of cure reduced, and the heat of reaction increased. The simulated cure behavior from the DSC data showed that the degree of cure (α) maximum value of 71.25% was achieved at the highest heating temperature of 85 °C. For the low heating temperature, i.e., 5 °C, the maximum degree of cure (α) did not exceed 12% because there was not enough heat to activate the catalyst to crosslink further.

Keywords: DSC; autocatalytic model; cure behavior; cure kinetics; cure simulation; unsaturated polyester resin.

Grants and funding

The authors would like to acknowledge Wabash National Corporation, 3550 Veterans Memorial Pkwy S, Lafayette, IN 47909, USA, for the financial support of this work. This material is based upon work supported by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) under the Advanced Materials and Manufacturing Technologies Office (AMMTO), Award Number [DE-EE0010659], through IACMI-The Composites Institute, Knoxville, Tennessee. Funding for open access to this research was provided by University of Tennessee’s Open Publishing Support Fund under funding number [006301].