Abstract
The volatiles release is a significant factor in the formation of voids during the autoclave and out-of-autoclave (OoA) curing processes for thermoset composites. However, the impact of curing on volatile release behavior in complex resin systems remains poorly understood. This study investigates the mechanisms by which the cure cycle impacts volatile release in carbon fiber-reinforced bismaleimide composite laminates. Gas chromatography mass spectrometry and thermogravimetric analysis (TGA) were used to determine the volatile composition and mass fraction. The results reveal that m-Aminophenylacetylene 3-Aminooxy-1-propanamine dominates the volatile composition, and its mass fraction increases with temperature, reaching 9.1% at 140°C. However, employing a cure cycle with a low heating rate of 0.5°C/min and a cure temperature of 140°C only yields a 6.1% volatile release. The reduction of volatiles release can be attributed to the temperature-dependent competition between volatile diffusion and curing reactions. Microscopic analysis demonstrates that the porosity of laminates produced via autoclave and OoA processing decreases as laminate thickness, moisture content, and volatile content decrease. The findings indicate that degassing at elevated temperatures can reduce intrinsic volatile content prior to the OoA process, thus reducing void content.
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