Dynamic behavior and thermal analysis of PLLA-g-CNC/PLLA bionanocomposites

Cellulose nanocrystals (CNCs) are natural source nanorods extracted from cotton, and have a poor dispersion in biocompatible and biodegradable PLLA matrix, because of their difference in polarity. Long chain surface grafting of L-lactide onto CNCs in Dimethyl formamide (DMF) via ring opening polymerization results in uniform dispersion of CNCs in PLLA matrix produced by solution mixing using chloroform. PLLA has a poor crystallization behavior, and adding surface modified CNCs by L-lactide improves its crystallization and increases its crystallization kinetics. Because of rod-like nature and high aspect ratio of CNCs, induction of β- phase crystals can be observed. Thermal behavior of bionanocomposites of modified and unmodified CNCs has been explored by DSC analysis. Dynamic nature of these bionanocomposites has been studied by temperature sweep mode of DMTA. Induction of β- phase crystals has been explored by XRD analysis. Thermogravimetric analysis showed a reduced thermal stability for nanocomposite of modified CNC and PLLA-g-CNC.