Oxygen Barrier Performance of Poly(vinyl alcohol) Coating Films with Different Induced Crystallinity and Model Predictions

Abstract

The presence of the crystalline regions in poly(vinyl alcohol) coating films acts as barrier clusters forcing the gas molecules to diffuse in a longer pathway in the amorphous region of the polymer, where diffusivity and solubility are promoted in comparison. Evaluating the influence of crystalline regions on the oxygen barrier property of a semi-crystalline polymer is thus essential to prepare better coating films. Poly(vinyl alcohol) coating films with varying induced crystallinity were prepared on a polyethylene terephthalate (PET) substrate by drying at different annealing temperatures for 10 min. The coating films were first delaminated from the PET substrate and then characterized using Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and X-ray diffraction (XRD) techniques to determine and confirm the induced percentage of crystallinity. The barrier performance of the coating films, i.e., the oxygen transmission rate (OTR), was measured at room temperature. Results showed a decrease in the OTR values of poly(vinyl alcohol) film with an increase in the degree of crystallinity of the polymer matrix. Tortuosity-based models, i.e., modified Nielsen models, were adopted to predict the barrier property of the semi-crystalline PVOH film with uniform or randomly distributed crystallites. A modified Nielsen model for orderly distributed crystallites with an aspect ratio of 3.4 and for randomly distributed crystallites with an aspect ratio of 10.4 resulted in a good correlation with the experimental observation. For the randomly distributed crystallites, lower absolute average relative errors of 4.66, 4.45, and 5.79% were observed as compared to orderly distributed crystallites when the degree of crystallinity was obtained using FTIR, DSC, and XRD data, respectively.

Effect of polyethylene internal structure on antibacterial properties of nanosilver composites

“…It can be seen from Table 4 that the crystallinity of EVA, POE, LDPE, and HDPE are 33.74%, 37.58%, 40.20%, and 56.59%, respectively. The low crystallinity of the composite means that it has less crystal structure and shows weak barrier properties 31,32 . The nanosilver mixed in the materials is easier to bypass the crystal area to reach the surface.…”

“…Both studies only considered the influence of different nanosilver composites on antibacterial properties from the factor of water absorption, but did not systematically elaborate on how the material structure affects antibacterial properties. In addition, some studies have proved that the different crystallinity of polymer materials will affect the barrier properties of materials 30–32 . The barrier properties of polymers were reported to be boosted by their increased crystallinity.…”

Effect of PVOH/PLA + Wax Coatings on Physical and Functional Properties of Biodegradable Food Packaging Films

“…In this regard, the deposition of functional bio-based coatings is a promising approach to improving the surface characteristics of substrates (i.e., adhesion, wettability, water repellence, anti-corrosion, antioxidant, antimicrobial and gas barrier properties) without compromising the biodegradable and/or recyclable features [ 17 ]). Polymeric coatings based on chitin nanofibrils, chitosan or PLA-based composites demonstrated their effectiveness for antimicrobial packaging [ 18 , 19 , 20 , 21 , 22 , 23 ]; hydrophobic properties can be imparted by including chitin or waxes [ 24 , 25 , 26 ] or by acrylic-modified crosslinkable chitosan nanocoatings [ 27 ]; among efficient oxygen-barrier layers, crosslinked proteins [ 28 , 29 , 30 , 31 , 32 ], cellulose nanocrystals [ 33 , 34 , 35 ] and poly(vinyl alcohol) [ 36 , 37 , 38 , 39 , 40 ] have recently received attention due to their excellent barrier performance.…”

Systematic study on fabrication of hollow poly(vinyl cinnamate) particles by particulate interfacial photocrosslinking

“…Furthermore, we applied the interfacial photocrosslinking reaction to poly(vinyl alcohol) (PVA) derivatives [poly(vinyl cinnamate), (PVC)] for the first time, to fabricate hollow polymer particles in this study (Scheme 1). PVA is a biodegradable synthetic polymer [36,37] used industrially as adhesives, [38,39] films, [40] and heterogeneous polymerization stabilizers; [41,42] PVC was prepared as the photoreactive polymer by the esterification of PVA with cinnamoyl chloride. The insight into the interfacial photocrosslinking process obtained in this study is useful for creating and designing future hollow polymer particles.…”