Poly(L‐Lactide‐Co‐ ε ‐Caprolactone)/glass Fiber Composites: Toward Improved Mechanical Properties of Polylactide‐Based Composites

ABSTRACT Inherent brittleness and limited toughness of polylactide (PLA) restrict its use in high‐performance applications. To overcome these limitations, poly(L‐lactide) (PLLA) is often blended with more ductile thermoplastics or chemically modified through copolymerization with other cyclic esters such as ε ‐caprolactone ( ε ‐CL). This article reports the study of the mechanical properties of poly(L‐lactide‐co‐ ε ‐caprolactone)/glass fiber composites produced by thermoplastic resin transfer molding (TP‐RTM) in one‐step synthesis via in situ copolymerization of L‐lactide (L‐LA) and ε ‐CL into the mold with pre‐disposed glass fibers. The influence of ε ‐CL content in the PLLA‐based copolymer matrix on the resulting mechanical properties of these composites, compared to pure PLLA/glass fiber analogues, was evaluated. Mechanical testing, including tensile, three‐point bending, and impact tests, was conducted. Composites achieved Young's modulus above 6.5 GPa and bending modulus over 10.3 GPa. An increase of 90% in the absorbed energy was observed for composites containing 30% of ε ‐CL in the matrix compared to pure PLLA‐based composites. Finally, the morphology and fracture of the composites were observed by optical microscopy, revealing a good impregnation of fibers by the matrix.