Microwave curing of carbon fiber/bismaleimide composite laminates: Material characterization and hot pressing pretreatment

• Microwave curing uniformity is verified by consistency of mechanical strength.
• Microwave curing with hot-press pretreatment is proposed to improve part quality.
• Microwave manufacturing cycle for composites is 37% of thermal processing cycle.
• Microwave cured panels show superior properties to those cured in thermal oven.
• Microwave panels with hot press have slightly better properties than autoclaving.

Microwave curing is proposed as an alternative cost-effective process to thermal curing for composite materials. Carbon fiber/bismaleimide composite laminates were fabricated by vacuum assisted microwave processing without arcing. The physical and mechanical properties of cured composites were compared to those produced using autoclave and conventional oven curing. To compensate for the lower vacuum pressure and further improve part quality, hot pressing pretreatment and subsequent microwave radiation were studied. The results indicated that microwave cured samples with 37% of the thermal manufacturing cycle time, obtained basically identical molecular structure and exhibited full curing. Uniformity and consistency of microwave curing was verified by assessing the mechanical strength at different positions in a laminate. The microwave processed panel properties showed a noticeable enhancement as compared with those cured in a traditional oven. A slightly superior performance to autoclave laminates was observed for the composites manufactured with the hot-pressing pretreatment followed by microwave processing.

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