Fully thermoplastic honeycomb sandwich composites produced by fusion bonding

A new method is proposed to create fully thermoplastic sandwich panels by fusing a cellular Polyetherimide (PEI) core with a polyaryletherketone (PAEK) facing through infrared heating of the skin followed by rapid pressing. The process eliminates the need for adhesives, reducing weight and cycle times while enhancing recyclability. The effects of processing temperature on core erosion, skin-core adhesion, and crystallinity of the PAEK matrix were investigated. Results show that higher temperatures lead to increased core erosion but also improve skin-core adhesion up to a certain point. The optimal processing temperature range was found to be around 310–320°C, where a balance between minimal core erosion and maximal adhesion strength is achieved. Flatwise tensile testing demonstrated that samples processed at 310–320°C exhibit both adhesive and core tensile failure modes, with higher strengths achieved at these temperatures. The method requires optimal tuning of the processing parameters and core geometry to achieve reliable and strong bonds between the core and skin. This research contributes to the development of sustainable manufacturing methods for thermoplastic sandwich structures, offering potential applications in aerospace and other industries where lightweight, high-performance materials are critical. Future work will focus on scaling up this technology and exploring its applicability to more complex geometries and material combinations.