Water and gas barrier properties of polyvinyl alcohol (PVA)/starch (ST)/glycerol (GL)/halloysite nanotube (HNT) bionanocomposite films: Experimental characterisation and modelling approach

摘要

In this study, ecofriendly polyvinyl alcohol (PVA)/starch (ST)/glycerol (GL)/halloysite nanotube (HNT) bionanocomposite at HNT contents of 0.25, 0.5, 1, 3 and 5 wt% were prepared in a solution casting process. Barrier properties against water vapour and gases of such bionanocomposite films were detected to consistently improve with increasing the HNT content when compared with those of PVA/ST/GL blends owing to tortuous paths generated at different HNT dispersion levels. Water vapour permeabilities of such blends and corresponding bionanocomposites increased in a linear manner when the temperature and relative humidity gradient increased from 25 to 55 degrees C and 10%-70%, respectively. Nonetheless, such permeabilities of bionanocomposites appeared to be less dependent of temperature and relative humidity gradient with increasing the HNT content. An accurate measurement of HNT aspect ratios with the aid of atomic force microscopy (AFM) yielded better agreement between experimental data and Nielsen model with respect to relative permeability of bionanocomposites. Overall, our fabricated bionanocomposites demonstrated good water and gas barrier properties to prolong the shelf life of avocados and peaches with great potential of being used as effective food packaging materials.