Ordered long polyvinyl alcohol fiber-reinforced thermoplastic starch composite having comparable mechanical...

A novel strategy is proposed to fabricate ordered long polyvinyl alcohol fiber (PVAF)-reinforced thermoplastic starch (TPS) composites with significantly improved mechanical properties. The PVAFs were uniformly fixed on two rods first; then sandwich-like TPS/fibers/TPS composite films were prepared by hot pressing, and PVAFs (0-4.08 wt%) with the same orientation were added to the composite films. The tensile test demonstrated that the tensile strength of the PVAF/TPS composite film improved from 2.13 MPa for TPS to 20.98 MPa with 4.08 wt% PVAFs, which is higher than the tensile strength of polyethylene (PE) (11.88 MPa) and polypropylene (PP) (19.29 MPa) and ten times higher than that of TPS. The sandwich-like cross-section of the composite film was observed by scanning electron microscopy to prove the better compatibility between PVAF and TPS. The nanoindentation test revealed that the addition of fibers improved the elastic modulus and hardness of the surface of the material. The strengthening mechanism for different PVAF contents was simulated by finite element analysis and attributed to the reduced maximum von Mises stress at the interface between the fiber and the TPS matrix, avoiding the stress concentration and corresponding fracture. This study provides a new way to prepare degradable composite films with suitable mechanical properties to replace PE or PP.