All-thermoplastic poly(L-lactide) / polyethylene terephtalate biocomposites in one step production by TP-RTM: manufacturing, characterization and mechanical recycling

To address environmental concerns, replacing thermoset matrices by thermoplastic ones has become a major focus in composite development. Biobased and industrially compostable polylactide, displaying good mechanical performances, is a matrix of choice to design biocomposites. This work reports the manufacturing of fully thermoplastic biocomposites combining poly(L-lactide) (PLLA) matrix and polyethylene terephthalate (PET) fabrics via thermoplastic resin transfer molding (TP-RTM) process through in-situ L-lactide polymerization catalyzed by tin (II) octoate. PLLA matrices, with L-LA conversions up to 97%, displayed weight-average molar masses over 140,000 g/mol. The resulting biocomposites exhibited an impact strength up to 99 kJ/m², flexural strength of 115.6 MPa, and modulus of 4.3 GPa. Mechanically recycled plates with 5 wt% compatibilizer reached a Charpy impact strength of 14.7 kJ/m². To date, all-thermoplastic composites have never been produced by 2 TP-RTM process. These new biocomposites represent an unprecedented way to promote the development of eco-friendly recyclable composite materials.