Mussel-inspired polydopamine-modified cellulose nanocrystal fillers for the preparation of reinforced and UV-shielding poly (lactic acid) films

To improve the inherent properties of polylactic acid (PLA), cellulose nanocrystals (CNCs) have been picked up as the nanofillers. However, the hydrophilic CNCs show poor compatibility with hydrophobic PLA, which usually fails to improve the performance of PLA. Inspired by mussel, polydopamine (PDA) decorated CNCs (PDA@CNCs) were utilized as nanofillers for PLA modification. With the introduction of PDA grafting on the surface of CNCs, the compatibility of CNCs in the PLA matrix was improved. The PDA acts as the bridge to enhance the interfacial adhesion between CNCs and PLA, improving the mechanical properties of the composite. At low addition level (1 wt%), the obtained composites (PDA@CNCs/PLA) showed enhanced mechanical properties 17.31% and 33.01% increases for tensile strength and elongation at break, respectively. In addition, the existence of PDA with UV radiation absorption performance induces PDA@CNCs/PLA UV-shielding property, which could undoubtedly extend the cycle time of the product and has the potential to be used in packaging for light-sensitive foods, pharmaceuticals, etc. The mussel-inspired PDA decoration of CNCs by this work provided a new strategy for the enhancement of the inherent properties of PLA.

Automated summary

Mussel-inspired polydopamine decorated cellulose nanocrystals were used as nanofillers to improve the compatibility and mechanical properties of polylactic acid. The introduction of polydopamine enhanced the interfacial adhesion between the nanocrystals and polylactic acid, resulting in improved tensile strength and elongation at break. The polydopamine also provided UV-shielding properties, making it suitable for light-sensitive packaging applications.