Water Resistance and Biodegradability of PVA/HNT Bionanocomposite Films

Abstract

Water resistance is evaluated for polyvinyl alcohol (PVA)/starch (ST)/glycerol (GL)/halloysite nanotube (HNT) bionanocomposite films as one of the fundamental requirements for food packaging materials. The incorporation of HNTs at the HNT contents between 0.25 and 1 wt% reduces the water absorption capacity and water solubility of bionanocomposite films by 42 and 48.05%, respectively, when compared with those of PVA/ST/GL blends. This is because of the moderate hydrophobicity of HNTs, as evidenced by increasing water contact angle of bionanocomposite films linearly by 21.36o with increasing the HNT content from 0 to 5 wt%, while slight improvements in water absorption capacity and water solubility of bionanocomposite films have been recorded beyond 1 wt% HNTs due to their typical agglomeration issue. Moreover, the presence of HNTs reduces the biodegradation rate of bionanocomposite films as opposed to PVA/ST/GL blends despite still being better than neat PVA films in view of their morphological structures.