A comparative study on the mechanical, thermal, and water barrier properties of PLA nanocomposite films prepared with bacterial nanocellulose and cellulose nanofibrils

Abstract

Mechanical, thermal, and water barrier properties of poly(lactic acid) (PLA) film reinforced with cellulose nanofibrils (CNF) and bacterial nanocellulose (BNC) were studied and compared. The in-situ formation of sodium carbonate (Na2CO3) on the BNC surface may aid in reducing the interchain hydrogen bonding and agglomeration of BNC fibers. At optimum loading, both CNF/PLA and BNC/PLA nanocomposite films exhibited higher tensile strength and Young’s modulus than the neat PLA without sacrificing its toughness. The BNC/PLA nanocomposite films displayed lower water vapor transmission rate (WVTR) as compared to neat PLA and CNF/PLA films at 0.5 and 1.0 wt%. BNC was found to induce imperfect crystal structures and exhibited higher overall crystallinity than neat PLA and CNF/PLA composites at 0.5 wt%. The BNC/PLA showed higher mechanical properties than CNF/PLA nanocomposites. Nanocellulose derived from plants and bacteria could provide promising solutions to develop high performance biobased-nanocomposites film for packaging application.