Enhancing mechanical properties of poly(lactic acid) through its in-situ crosslinking with maleic anhydride-modified cellulose nanocrystals from cottonseed hulls

Cellulose nanocrystals (CNCs) were extracted from waste cottonseed hulls, The obtained CNCs were grafted with maleic anhydride (MA) and then in-situ crosslinked with Poly(lactic acid) (PLA) using dicumyl peroxide (DCP) as the crosslinking initiator. MA-grafted CNCs (MACNCs) exhibited improved dispersion state than that;of pristine CNCs in the PLA matrix. The in-situ crosslinking reaction further provided a strong bridge for chemical bonding between MACNCs and PLA. The resultant PLA/MACNC composites showed a comprehensive improvement in both tensile and thermomechanical performances. At the 5 wt.% loading rate of MACNCs, the ultimate tensile strength and Young's modulus of crosslinking PLA/MACNC composites reached 56.3 and 1550 MPa, respectively, representing 73.2% and 122.7% increases compared with these of pristine PLA/CNC composite. Dynamic mechanical analysis results indicated that the crosslinking PLA/MACNCs film had the highest storage modulus in both the glassy (30 degrees C) and rubbery (80 degrees C) stages.