Investigation on Seawater Ageing of PET-Epoxy Composites: An Ecological and Sustainable Approach for Marine Applications

The effect of sea water immersion on the durability and performance of the PET fibre reinforced epoxy composites were experimentally investigated. The reinforcing fibres and their respective composite samples were immersed in artificial seawater over a period of 120 days. The extent of degradation post immersion was studied using thermal gravimetric analysis. Water uptake behaviour of the composites and the losses in their mechanical properties were studied by testing them under tensile, flexural and impact loads before and after immersion. Effect of degradation in interfacial region and the fracture morphology in the failed samples were analysed through SEM micrographs. The outcome of these results was compared with the glass fibre reinforced epoxy counterparts, which are often used in today’s marine structures. It was found that the glass–epoxy composites experienced about 8% decrease in their overall mechanical properties while polyester-epoxy composites remain unaffected to seawater ageing. Therefore, PET-epoxy material combinations can be approached to cater the long term structural requirements of maritime applications and further open up new gateways for utilization of recycled hazardous plastics.