Synchronously Enhancing Crystallization Ability and Mechanical Properties of the Polylactide Film via Incorporating Stereocomplex Crystallite Fibers

Poly(L-lactic acid) (PLLA) has been widely concerned because of its excellent biodegradability and biocompatibility. However, the poor crystallization ability of PLLA during the molding process not only leads to weak mechanical properties but also reduces the processing efficiency, which limits the application of PLLA greatly. Enhancing crystallization ability of PLLA via introducing inorganic nanoparticles usually sacrifices biodegradability or transparency. Here, the microfine fibers with stereocomplex (SC) crystallites were incorporated into PLLA film to tailor the crystallization ability of PLLA as well as the mechanical properties. The results confirmed that the crystallization ability of PLLA matrix under different circumstances could be greatly enhanced by a few amounts of SC crystalline fibers, and synchronously enhanced tensile strength and ductility were also achieved, especially at relatively high temperature. Due to the relatively homogeneous dispersion of SC crystalline fibers and the similar refractive index between components, the PLLA-based film also exhibited high transparency, up to 85%-90% depending on the content of SC crystalline fibers. This work provides guidance for manufacturing transparent PLLA-based packaging materials with good crystallization capability and mechanical properties.