Thermally recyclable polylactic acid/cellulose nanocrystal films through reactive extrusion process. (22nd March 2016)

• Record Type: Journal Article
• Authors: Dhar, Prodyut; Tarafder, Debashis; Kumar, Amit; Katiyar, Vimal
• Is Part Of: Polymer. Volume 87(2016)
• Page Start: 268
• Page End: 282
• Publication Date: 2016-03-22
• Subjects: Cellulose nanocrystal -- Polylactic acid -- Nanocomposites; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2016.02.004
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: This paper reports a single step reactive extrusion process for fabrication of thermally stable, polylactic acid grafted cellulose nanocrystal(PLA- g -CNC) nanocomposite films using dicumyl peroxide as crosslinking agent. PLA- g -CNC nanocomposites were recycled without significant breakage in the molecular structure of PLA. The grafted PLA chains shields the sulfate and hydroxyl groups of CNCs, thereby enhancing the compatibilization with PLA matrix and preventing thermal degradation during extrusion. NMR and FTIR spectroscopy studies showed that amorphous PLA chains grafted on CNC surface through C–C bonds formation. Presence of such chemical crosslinks led to efficient transfer of modulus of CNCs to PLA matrix, thereby improving the tensile strength and young's modulus by∼40% and∼490%, respectively. Recycling of PLA- g -CNC doesn't alter the molecular weight, thermal, crystallization and mechanical properties of the nanocomposites significantly. Therefore, the current study provides a novel approach for fabricating CNC-reinforced-PLA nanocomposites which can be easily recycled and reused for multiple cycles. Graphical abstract: Highlights: PLA chains grafted onto CNC surface (PLA- g -CNC) through C–C bond formation in presence of dicumyl peroxide radical. PLA- g -CNC nanocomposite films were found to be thermally stable and could be recycled. PLA- g -CNC films shows uniform dispersion of CNC due to the efficient grafting, results in improvement in tensile strength. Crystalline behavior and elastic properties of resulting composites improved with increase in the CNC loadings.