This review exclusively addresses material systems primarily based on poly (vinyl-alcohol) (PVA), one of the most popular water soluble biopolymers, for their use in packaging applications with the primary objective of reducing petro-based plastic waste. In addition, some typical PVA blends and nanocomposites are discussed as comparative studies for material packaging. Structural characteristics, mechanical, thermal and barrier properties, in addition to biodegradation of these multiple material systems, are summarised in a systematic manner.Finally, associated fabrication processing methods together with the most popular theoretical models used for the permeability of PVA nanocomposites are also reviewed in detail.

As a novel biodegradable material, poly (vinyl) alcohol (PVA)/starch (ST)/ glycerol (GL)/ halloysite nanotube (HNT) nanocomposite films were prepared by solution casting at the HNT contents of 0.25, 0.5, 1, 3, and 5 wt%. Water absorption capacity and water solubility of nanocomposite films were decreased remarkably by 44.24 and 48.05%, respectively, with increasing the HNT content from 0 to 5 wt% when compared with those of biopolymer matrices. Moreover, the water contact angle of nanocomposite films increased by 21.36 • with the incorporation of HNTs. The presence of HNTs appeared to reduce the overall migration rates for PVA/ST/GL/HNT nanocomposite films when interacting with either hydrophilic or lipophilic food simulants. However, the migration rates of HNTs alone were enhanced with increasing the HNT content in hydrophilic, lipophilic, and acidic food simulants. On the other hand, the biodegradation rate and light transmittance of nanocomposite films were reduced linearly by 18.56 and 26.90% with increasing the HNT content from 0 to 5 wt%. Overall, novel PVA/ST/GL/HNT nanocomposite films in this study offer highly competitive materials with excellent water resistance, good biodegradability, and acceptable transparency to be potentially used for sustainable food packaging particularly targeting lipophilic and acidic foodstuffs.

Poly (vinyl) alcohol (PVA)/starch (ST) films (weight ratio: 80/20) were prepared using a solution casting method, in the presence of 30 wt% glycerol (GL) as a plasticiser. Halloysite nanotubes (HNTs) was used as relatively new clay nanofillers to PVA/ST/GL blends for more economical material packaging. HNTs at filler loadings of 0.25, 0.5, 1, 3 and 5 wt% were incorporated to enhance the mechanical and thermal properties of resulting PVA/ST/HNT nanocomposites. The tensile strength of such nanocomposites was found to be improved by 20 and 3.4%, respectively, with the inclusion of 0.25 and 0.5 wt% HNTs as opposed to those of PVA/ST/GL blends. However, a decreasing strength trend was observed beyond the HNT loading of 0.5 wt% due to HNT agglomeration, as evidenced by relevant micrographs via scanning electron microscopy (SEM). However, Young's modulus was enhanced by 148% with the addition of 1 wt% HNTs when compared with PVA/ST/GL blends. X-ray diffraction (XRD) analysis is indicative of slightly intercalated nanocomposite structures formed at low HNT loadings of 0.25 to 1 wt%. In general, the incorporation of HNTs improved the thermal stability of PVA/ST/GL blends by increasing melting and decomposition temperatures along with the reduction of weight loss.

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Starch nanocomposites are popular and abundant materials in packaging sectors. The aim of this work is to review some of the most popular starch nanocomposite systems that have been used nowadays. Due to a wide range of applicable reinforcements, nanocomposite systems are investigated based on nanofiller type such as nanoclays, polysaccharides and carbonaceous nanofillers. Furthermore, the structures of starch and material preparation methods for their nanocomposites are also mentioned in this review. It is clearly presented that mechanical, thermal and barrier properties of plasticised starch can be improved with well dispersed nanofillers in starch nanocomposites.