Simple but efficient preparation of high-strength, heat-resistant, and high-barrier PLA/TOBC plastic packaging containers via pickering emulsion

Bio-based polylactic acid (PLA) with degradable, environmentally friendly and bio-friendly properties has become important sustainable material. However, the inherent disadvantages of PLA, such as weak crystallization ability, poor thermal stability, and poor barrier properties, limit its application in areas such as Plastic packaging-Containers. In this paper, a simple but efficient method was established to decrease effect of inherent disadvantages of PLA and expand its application, is by pickering emulsion. Food sources bacterial cellulose blocks were oxidized and followed high-pressure homogenization to prepare nano-bacterial cellulose (TOBC) as amphiphilic emulsifier, then TOBC nanofibers coated/stabilized PLA microspheres were prepared via pickering emulsion method, that avoiding the problem of interface separation between nanocellulose and PLA. As a result, TOBC served as a heterogeneous nucleating agent to greatly improve the crystallization behavior of PLA, boosting the crystallinity of the composite from 21.8 % to 49.6 %. After hot-pressing or injection processing to a shaped material, the prepared PLA/TOBC composites exhibited the excellent combined properties with tensile strength of 66.2 MPa, flexural strength of 81.22 MPa, impact strength of 2.72 kJ/m² and Vicat softening temperature of 167.3 °C. Meanwhile, TOBC addition also greatly improved the oxygen barrier ability of the composite, and the oxygen transmission rate was reduced from 143.77 cm³/(cm²-24h-0.1 MPa) for PLA to 16.01 cm³/(cm²-24h-0.1 MPa) for PLA/TOBC-3. This means that PLA/TOBC composites are expected to be used as environmentally friendly Plastic packaging-containers with high barrier capacity, providing new ideas for the development of Plastic packaging products.