Polyvinyl alcohol (PVA) is used in many applications because of its excellent physicochemical properties, non-toxicity, and biodegradability. However, its relatively low water resistance, poor water vapor/ultraviolet (UV) barrier properties, and poor mechanical properties compared with conventional polymers limit its applications in food packaging. In this study, cellulose nanocrystals (CNCs) and alkyl ketene dimer (AKD) were used to overcome these issues. The mechanical properties, water resistance, and barrier properties of the developed PVA/CNC/AKD films were significantly improved relative to those of a neat PVA film. The mechanical strength of a PVA/CNC/AKD 15% film (15 wt% AKD in a PVA/CNC matrix of 5 wt% CNCs) was 64.6% and 37% higher than those of PVA and PVA/CNC films, respectively. The water vapor transmission rate, water absorption, and solubility of PVA/CNC/AKD 15% were 41.2%, 61.1%, and 92.9%, respectively (lower than those of the neat PVA film). In addition, the UV barrier properties and soil degradation of the PVA/CNC/AKD films were significantly improved.
Keywords: Alkyl ketene dimer; Cellulose nanocrystals; Mechanical strength; Polyvinyl alcohol; UV barrier properties; Water vapor barrier properties.
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