Modified cellulose nanocrystals based on SI-ATRP for enhancing interfacial compatibility and mechanical performance of biodegradable PLA/PBAT blend

To make up for the brittleness of poly(lactic acid) (PLA), people usually introduce flexible poly(butylene adipate- co -terephthalate) (PBAT) which greatly reduces the strength and limits toughening effect due to unfavorable immiscibility of the blends. Herein, functionalized biodegradable cellulose nanocrystals (CNCs) were used as enhancement to simultaneously improve strength and toughness of PLA/PBAT blend. To improve the interaction between PLA and PBAT, poly(glycidyl methacrylate) (PGMA) was grafted on the surface of CNC via a surface-initiated atom transfer radical polymerization reaction. After the addition of CNC-PGMA30, the phase size of PLA/PBAT (70/30 wt%) reduces dramatically, showing improved interfacial compatibility between PLA and PBAT. Meanwhile, prepared PLA/PBAT/CNC1.0-PGMA30 composite has tensile strength of 49.6 MPa and elongation at break of 268.5%, demonstrating considerably increased strength and toughness in comparison to the pure PLA/PBAT blend.