Strong and Tough Polylactic Acid Based Composites Enabled by Simultaneous Reinforcement and Interfacial Compatibilization of Microfibrillated Cellulose

As one of the most important biobased and biodegradable polymers with a promising commercial prospect, polylactic acid (PLA) has gained increasing interest. Nevertheless, its high mechanical strength is generally sacrificed when using tough matters to overcome its inherent brittleness. Concerning to develop strong and tough PLA-based materials, herein, polybutylene succinate (PBS) is blended with PLA, and epoxidized microfibrillated cellulose (MFC-EPI) is employed as an interfacial compatibilizer as well as a reinforcement filler. Effects of the amounts of PBS and MFC-EPI on crystallization behavior, thermal stability, and mechanical properties of the PLA-based materials are investigated. Notably, tensile strength and elongation at break of the resultant composite containing 2% MFC-EPI are up to 71.4 MPa and 273.6%, respectively. The "bridge" effect of the filler contributes to energy transfer and dissipation during deformation, accounting for the toughening mechanism that is confirmed by microscopy. Such a "two-in-one" modification strategy ensures the high strength and toughness, which can be used to develop more materials with high mechanical performances.