Cellulose nanocrystals (CNCs) are renewable and sustainable filler for polymeric nanocomposites. However, their high hydrophilicity limits their use with hydrophobic polymer for composite materials. In this study, freeze-dried CNCs were modified by transesterification with canola oil fatty acid methyl ester to reduce the hydrophilicity. The transesterified CNCs (CNCFE) were compounded with PLA into nanocomposites. CNCFE with long-chain hydrocarbons plays a role as plasticizer. Increasing CNCFE loadings resulted in clear plasticizing effects. Lower Tg and Tm were achieved for CNCFE-based nanocomposites. Plasticizing nanocomposite melt with CNCFE can mitigate the degradation of CNCs during thermal processing. The elongation at break of nanocomposites containing 5% CNCFE was increased. Dynamic rheological study showed the highest elastic and viscous moduli (G′ and G″) and complex viscosity (G*) of nanocomposites with addition of 2% CNCFE. By tailoring the loadings of the transesterified CNCs, tunable structure and properties of nanocomposites can be obtained.
Wei, Liqing; Luo, Shupin; McDonald, Armando G.; Agarwal, Umesh P.; Hirth, Kolby C.; Matuana, Laurent M.; Sabo, Ronald C.; Stark, Nicole M. 2017. Preparation and characterization of the nanocomposites from chemically modified nanocellulose and poly(lactic acid). Journal of Renewable Materials. 5(5): 410-422.