In-situ polymerized cellulose nanocrystals (CNC) poly(L-lactide) (PLLA) nanomaterials and applications in nanocomposite processing

CNC-PLLA nanomaterials were synthesized via in-situ ring-opening polymerization of L-lactide in the presence of CNC, resulting in hydrophobic, homogeneous mixture of PLLA-grafted-CNC and free PLLA homopolymer. The free PLLA serves two useful functions: as barrier to further prevent PLLA-g-CNC from forming aggregates, and in creating improved interfacial properties when these nanomaterials are blended with other polymers, hence enhancing their performance. CNC-PLLA nanomaterials can be used for medical or engineering applications as-they-are or by compounding with suitable biopolymers using versatile techniques, such as solution casting, co-extrusion or injection molding, to form hybrid nanocomposites of tunable mechanical properties. When compounded with commercial-grade PLA, the resulting CNC-PLA nanocomposites appear transparent and have tailored (dynamic and static) mechanical and barrier properties, approaching those of poly( ethylene terephthalate), PET. The effect of reaction conditions on the properties of CNC-PLLA nanomaterials have been carefully studied and detailed throughout the paper. (C) 2016 Elsevier Ltd. All rights reserved.