Utilization of waste polyethylene terephthalate felt in hybrid polymer composites: A sustainable approach for recycling and mechanical property enhancement

The waste polyethylene terephthalate (PET) as a continuous fiber reinforcement is utilized in hybrid arrangement with flax fiber in thermosetting polymer composites to provide alternative for PET recycling. The flexure properties and Izod impact energy of different hybrid configurations are compared with their virgin counterparts. Moreover, engineering data for Pure PET/VE (Vinyl ester) composite and pure flax/VE composite are generated to perform analytical and numerical analysis as well. The results from the flexural test show that the interlaminar hybridization of flax/PET has no significant contribution to the flexural strength compared with the virgin flax/VE and PET/VE composites but the modulus exhibited an increment of almost 50% in both 8/2 and 5/5 flax/PET hybrids. The absorbed energy during Izod impact was maximum for PET/VE composite and 2/8 flax/PET hybrid. The 5/5 flax/PET hybrid showed a 50% drop in the energy absorbed during the Izod impact test. The engineering data generated from the virgin composites was useful in predicting the modulus of hybrid composites using the classical lamination theory (CLT) with a maximum deviation of 18%, moreover, the flexural strength for the hybrids was closely predicted using the numerical analysis tool with a maximum deviation of 15%. Overall, the waste PET felt showed potential to be used in interlaminar hybrid arrangements with natural fiber to complement each other in mechanical properties in addition to being an alternative for not only recycling but manufacturing sustainable structures.