Investigation on Thermal and Structural Integrity of Aramid Fiber‐PEKK Polymer/XLPE Foam Sandwich Composites Under Elevated Temperature and Cryogenic Environments

ABSTRACT This work investigates the development of a sustainable composite material for cryogenic application. The composite plates are made of aramid fibers, which are high‐strength and low‐thermal conductive materials, and poly ether ketone ketone ( PEKK ) of service temperature 280 °C , an ultra‐high performance thermoplastic film. The surface of PEKK films was modified with nitrogen plasma to enhance the adhesive properties between the fiber and the film. The composite plates were fabricated through the film stacking method. The composite was fabricated with PEKK and aramid fiber fabric, and in between, two PEKK ‐aramid fiber composite cross‐linked polyethylene ( XLPE ) foam was sandwiched for thermal insulation by high‐temperature resistant epoxy adhesive. The hybrid composite was tested in exposure to dry ice and impact tests. The composite plates were cut into strips and were also exposed to a cryogenic atmosphere (liquid nitrogen at −196°C) and elevated temperature (heated in an oven at 250°C). Thermal fatigue tests and tensile tests were conducted on the strips. The results of the tests showed significant improvement in the composite material properties and proved to be sustainable in the cryogenic application. Analysis under Ansys Fluent software gave similar results for the composite.