Novel method of healing the fibre reinforced thermoplastic composite: A potential model for offshore applications

Continuous fibre reinforced thermoplastic composites are increasingly finding their use as engineering materials in many industries due to the excellent fire, smoke and toxicity performance. However, the composite component produced using automated continuous fibre reinforced thermoplastic tapes laying machine are susceptible to sudden failure emanating from microscale cracks. This study demonstrates the healing potential of a layered Glass Fibre Reinforced Polymer (GFRP) composite consisting of alternative layers of GFRP and a magnetic polyamide-6 (PA-6) nanocomposite (PNC) film. The self-healing process is presented in three steps, viz. (i) polymer nanocomposite synthesis, (ii) preparation of the layered GFRP layered composite sample and (iii) self-healing and testing of GFRP layered composite sample. Firstly, the multilayer dog bone sample consisting of a magnetic polymer nanocomposite (PNC) film sandwiched between thermoplastic unidirectional GFRP tapes are prepared. Healing is triggered by exposing the damaged multilayer sample to microwave causing selective heating of nanocomposite film and its subsequent melting. The healing process completes when liquid polymer fills the micro-crack in the multilayer tape through capillary action and solidifies upon cooling. The healing yields 84% of the undamaged tensile strength recovery. Results demonstrate the potential application of an autonomous self-healing method for thermoplastic composite used in the offshore environment.