Evaluation of Out-of-Autoclave (OOA) epoxy system

Abstract

Epoxy resins (EP) usually cure in autoclave to minimize resin voids and to achieve the desired resin/fiber ratio. Cure parameters such as temperature, vacuum and pressure levels are controlled and monitored. Aiming time and cost optimization, new out-of-autoclave (OOA) cure processes have been developed lately. This study evaluated the cure cycle and the effect of non-programmed interruptions in an OOA process. Fourier Transform Infrared spectroscopy (FT-IR) results show similarities between the resin used and diglycidyl ether of bisphenol A (DGEBA) and also that the curing system is composed of cyan and sulfur hardeners, codified in industry, as Components of #2511 Resin System. The cure cycle and its interruptions were simulated by dynamic-mechanical analysis (DMA). The samples obtained were evaluated by FT-IR and differential scanning calorimetry (DSC), whose results show that the degree of cure varying between 0.8 to 0.85 was achieved at 120 °C.