Super Toughened PLLA/PBAT Blends with Modified Phase Interface via Constructing Cocontinuous Structure with the Aid of Stereocomplex Crystallites Toward Preparation of a Fully Degradable Material

Presentation investigation was aimed at tailoring the interface of poly(l-lactide) (PLLA) and poly(butylene adipate-co-terephthalate) (PBAT) blend to create a co-continuous morphology of PBAT for preparing high toughness fully degradable material. To achieve this, compatibilizers of glycidyl methacrylate grafted poly(butylene adipate-co-terephthalate) (PBAT-g-GMA) and poly(D-lactide) (PDLA) were added to the PLLA/PBAT blend in the melt processing to reduce the interfacial tension and enhance interfacial strength. The results showed that the spherical PBAT particles uniformly distributed in the PLLA matrix with decreased size (from 0.60 to 0.33 μm) after introducing PBAT-g-GMA, but the stereocomplex (SC) crystallites formed between PDLA and grafted PLLA with PBAT-g-GMA located at the interface to induce the formation of branched co-continuous structure. With the combination of PBAT-g-GMA and PDLA, the super toughness PLLA/PBAT blend presented tensile strength, elongation at break, and notched impact strength above 32 MPa, 200%, and 77 kJ/m2, respectively. The morphology of the impact-fractured surface revealed that the energy was dissipated through plastic deformation together with voids and coarse fibers that occurred by the co-continuous structure. This work provides a facile strategy for the preparation of a ductile PLLA/PBAT blend.