Investigating the Effect of Temperature on the Curing Kinetics Behavior and Mechanical Properties of Epoxy‐Modified Polysulfide

ABSTRACT Epoxy‐modified polysulfide is widely used in coatings and as an adhesive for rocket insulation. Understanding the curing process is essential for enhancing the properties of the material. This research investigates the curing kinetics of epoxy‐modified polysulfide and examines how curing temperature influences its characteristics. In the study, epoxy, polysulfide, and cycloaliphatic amine curing agents are mixed and cured at 25°C, 40°C, and 60°C. The curing durations are determined based on a kinetics model. The curing kinetics are analyzed using differential scanning calorimetry (DSC), employing the Prout‐Tompkins autocatalytic method for modeling. Changes in molecular structure during the curing process are assessed using second derivative analysis from Fourier Transform Infrared Spectroscopy (FTIR). Additionally, the mechanical properties such as hardness, tensile strength, elongation, elastic modulus, and density are measured using a Shore D durometer, a universal testing machine, and a densitometer. Phase separation is examined with a scanning electron microscope (SEM). The results indicate that higher curing temperatures increase density, hardness, tensile strength, and elastic modulus by factors of 1.013, 2.38, 1.75, and 14.95, respectively, while reducing flexibility by 0.75 times. Although phase separation does not occur, higher temperatures do affect the product's opacity.