High-strength and high-modulus polyvinyl alcohol fiber reinforced polylactide composites based on needlepunched nonwovens

High-strength and high-modulus polyvinyl alcohol fiber (PVAF) reinforced polylactide (PLA) composites (PVAF/PLA-FRPs) with different fiber content were prepared by needlepunching nonwoven process, followed by hot pressing using PVAFs and PLA fibers as raw materials.The obtained PVAF/PLA-FRPs had excellent mechanical properties and isotropic characteristics.The tensile strength and initial modulus of machine and cross-machine direction of PVAF/PLA-FRP with 50% PVAF reached 154 MPa and 5.1 GPa, and 152 MPa and 5.2 GPa, respectively.The corresponding strain at break was 15.0 and 13.9%, respectively.PVAF/PLA-FRP with 50% PVAF presented higher tensile strength and strain at break than short fiber-reinforced PLA composites reported by other groups.The tensile destruction of PVAF/PLA-FRPs was attributed to both the pulling out of PVAF from the PLA matrix and the break of PVAF.In PVAF/PLA-FRPs, PVAF acted as an effective nucleating agent to promote the crystallization of PLA.