Fully bio-based polylactic acid composites based on molecular crosslinking interface engineering

The key to achieving high-performance plant fiber/polylactic acid (PLA) composites lies in solving the interfacial compatibility issue between the two components. However, current mainstream methods for interfacial modulation often come with energy consumption and environmental concerns. To address this, our study proposed the development of fully bio-based bamboo fiber (BF)/PLA composites based on the principles of non-toxicity, low carbon footprint, and environmental friendliness. In this study, we aimed to construct a molecular-scale multiphase crosslinking network structure in BF/PLA composites. To achieve this, we utilized cyclodextrins (CD) to induce a regularized alignment of PLA molecular chains and employed epoxidized soybean oil (ESO) ring opening reaction to form bonds connecting BF, CD, and PLA molecules. This approach ensured that the composite is fully bio-based while still exhibiting remarkable mechanical properties. The resulting BF/PLA@CD-ESO composites demonstrated impressive bending strength, reaching 108.65 MPa, which was 23.11 % higher than that of the BF/PLA composites. Moreover, the tensile strength reached 67.48 MPa, which was 39.06 % higher than that of BF/PLA composites. This study provides a convenient, green and sustainable method for preparing PLA-based composites. The resulting composites are expected to be used in disposable tableware, food packaging and environmentally friendly furniture.