Oxygen Transmission Rate Values Research Articles

Permeability and barrier layer properties of a woven carbon fibre polymer composite as battery packaging

Carbon fibre reinforced polymer (CFRP) laminates are used in various studies as Li-ion polymer (LiPo) batteries packaging. However, their suitability as a packaging material is not well understood. The present study investigates the liquid absorption (water and lithium bis(trifluoromethanesulfonic)imide (LiTFSI) electrolyte immersion tests) and barrier layer properties (water vapour transmission rate (WVTR) and oxygen transmission rate (OTR) tests) of a 200 gsm woven CFRP laminate to assess its suitability as a battery packaging material. This is the first study to show that prolonged immersion in battery electrolyte does not change the mechanical of a woven CFRP laminate. Hence, the CFRP laminate may be suitable for structural battery components, such as current collectors and electrodes. However, CFRP should not be used as battery packaging, as OTR and WVTR values of the CFRP laminate were found to be five and one order of magnitudes higher than typical battery pouch materials (i.e. aluminium foil), respectively.

Highly flame retardancy, barrier, mechanical and persistent antibacterial polylactic acid film with high-parallel interconnected thousand layered cake architecture

In this work, a bio-based material (CGP) is obtained by combing chitosan, gelatin and polyvinyl alcohol through a simple solution mixing to simultaneously address polylactic acid film (PLA)' flammability and poor barrier, toughness and antibacterial properties by soaking. The results of open fire testing show that modified PLA films can effectively prolong the combustion time, improve the thermal stability and reduce the release of heat in the cone calorimeter test. For the PLA sample after soaking for 5 times (PLA-5) in particular, it can reduce the peak heat release rate (pHRR) and total heat release (THR) values to 85.8 kW/m2 and 1.3 MJ/m2 from the values of 129.5 kW/m2 and 1.8 MJ/m2 for PLA, respectively. Structural analysis suggests that CGP primarily operates in the condensed phase by forming physical barriers. Meanwhile, the modified PLA films can exhibit superior barrier effects, which indicate the oxygen transmission rate value of PLA-5 decreases to 0.9 cm3/(m2·day) from the 392.5 cm3/(m2·day) of raw PLA film. Moreover, the PLA-5 also have excellent toughness (the value increased to 200.5 % from 31.0 %) and persistent antibacterial effects (it still has 100 % sterilization after 500 days).

Renewable thermoplastic starch/sugar alcohol blends and their oxygen barrier application

AbstractFully renewable oxygen barrier thermoplastic starch (TPS)/sugar alcohol blown films were innovatively prepared by blending proper loadings of Erythritol (ET), Sorbitol (ST), and Lactitol (LT) and supercritical carbon dioxide (scCO2) assistance. The oxygen transmission rate (OTR) values of the properly prepared scCO2TPSxETy, scCO2TPSxSTy, and scCO2TPSxLTy films reduced to 4.3, 6.6, and 12.5 cm3/m2∙day∙atm, which are about 5–28 times smaller than those of the conventional TPS films reported in the literature. The free‐volume‐cavity characteristics (FVCC) and OTR detected for TPSxETy (or scCO2TPSxETy), TPSxSTy (or scCO2TPSxSTy), and TPSxLTy (or scCO2TPSxLTy) films diminished to a minimum, as their ET, ST and LT loadings came near an optimal value. Slightly smaller OTR and FVCC values were detected for scCO2TPSxETy, scCO2TPSxSTy, and scCO2TPSxLTy films than those of corresponding TPSxETy, TPSxSTy, and TPSxLTy films prepared without scCO2‐assistance. The smallest OTR and FVCC detected for the properly prepared TPSxETy (or scCO2TPSxETy), TPSxSTy (or scCO2TPSxSTy), and TPSxLTy (or scCO2TPSxLTy) films diminished with decreasing sugar alcohol's molecular weight. An essential result is that the OTR of the properly prepared scCO2TPSxETy film was merely 4.3 cm3/m2∙day∙atm, which is small enough to meet the demand of high oxygen barrier packaging application. Dynamic molecular relaxations detected for these films disclosed that ET, ST, and LT were compatible with TPS, as their loads were ≤ the optimum value. The distinctly reduced OTR and FVCC for these properly prepared films are partially attributed to the reinforced molecular interactions between sugar alcohol and TPS's hydroxyl groups when they were prepared with scCO2‐assistance, optimal sugar alcohol loading, and/or smaller sugar alcohol's molecular weight.Highlights High oxygen barrier thermoplastic starch/sugar alcohol blown films were prepared. The lowest oxygen transmission rate of the renewable film was 4.3 cm3/m2∙day∙atm. This oxygen transmission rate is qualified for high oxygen barrier application. Boosted oxygen barrier property was ascribed to the reduced free volume values.

How to get reliable oxygen transmission rate values for coated cardboards?

Coated papers have emerged as alternatives to petroleum-based and non-biodegradable plastics, particularly in packaging industries. Indeed, barriers brought by the coating layer, toward oxygen for example, allow better food preservation. This growing interest in the field of packaging has led to the need to characterize the mass transfer properties of these materials, particularly oxygen. Although methods and standards to characterize these parameters have been developed for plastic materials, none have been specifically adapted for coated cardboards. This paper evidences a so-called “edge effect” occurring when characterizing the oxygen transmission rate (OTR) of single-side coated cardboards. This leads to two significantly different OTR values depending on the material's side, cardboard, or polymer coating, exposed to the oxygen flux. Over- or under-estimated OTR can have a significant impact on food preservation. Therefore, avoiding edge effects is essential for obtaining accurate oxygen transmission rate value. This study focuses on one measurement method and two cardboard supports. Depending on the equipment used and sample properties, different methods can be used to prevent edge effects and must be investigated on a case-by-case basis.

Effect of super critical carbon dioxide and alkali treatment on oxygen barrier properties of thermoplastic starch/poly(vinyl alcohol) films

Abstract Sustainable oxygen barrier thermoplastic starch (TPS)/polyvinyl alcohol (PVA) blown films were successfully prepared by blending proper PVA loads during NaOH-treating and supercritical carbon dioxide (scCO2) assisted processing. The NaOH-treated TPS or scCO2TPS films showed smaller free-volume-cavity characteristics (FVCC) and oxygen transmission rate (OTR) than those of TPS (or scCO2TPS) prepared without proper alkali-treatment. Smaller OTR and FVCC values were detected for NaOH-treated scCO2TPS films than those of NaOH-treated TPS films prepared without scCO2-assistance. All OTR and FVCC values detected for proper alkali-treated scCO2TPS y PVA z films diminished distinctly to a smallest value, when their PVA loads came near a solubility limit value of 27.5 wt%. An essential result is that the OTR of the optimal NaOH-treated scCO2TPS y PVA z film is merely 3.1 cm3/m2 day atm, which meets the requirement of high oxygen barrier plastics. Dynamic molecular relaxations and WAXD patterns detected for proper NaOH-treated scCO2TPS y PVA z films disclosed that PVA was compatible with TPS, as PVA loads were ≤ the solubility limit value. The distinctly reduced OTR and FVCC detected for optimal NaOH-treated scCO2TPS y PVA z films are partially attributed to the reinforced molecular interactions between hydroxyl groups of TPS and PVA, as they were blended with proper PVA loads during their alkali-treating and scCO2-aid processing.

Shelf Life and Safety of Vacuum Packed HPP-Treated Soaked Cod Fillets: Effects of Salt Content and Multilayer Plastic Film

High microbiological quality standards, food safety, and environmental sustainability represent crucial topics in food production chains. For this reason, fish industries, which import salted and seasoned fish products from supplier countries, i.e., Norway, Denmark, USA (Alaska State), etc., have tried to reduce the salt content of each carton during transportation (reducing carbon emissions and the weight of major quantities of transported fish). In the present study, 360 differently processed fish fillet samples, belonging to the species Gadus macrocephalus caught in FAO zone 67, were microbiologically and chemically screened. This study aimed to provide original data concerning the applicability of sustainable solutions investigating the combined effects of salt content reduction combined with new recyclable multilayer plastic film packaging (vacuum skin packaging with two different oxygen transmission rate values). The microbiological results showed no substantial changes comparing the two differently salted products, highlighting their high hygienic characteristics which were also observed in their chemical analysis. The shelf life evolutions (comparing the two different studied plastic films) highlighted that, after 35 days from HPP treatments, bacterial loads gained high values, over 6 log cfu/g. This study highlights that, compared to the currently used plastic films, the results of the new and sustainable multilayer plastic films show that they can provide safe food matrices in combination with HPP technologies. Therefore, this preliminary investigation brings closer attention to alternative and environmentally sustainable production systems with their designs based on the multidisciplinary approach of food production systems.

Hydrophilic Composites of Chitosan with Almond Gum: Characterization and Mechanical, and Antimicrobial Activity for Compostable Food Packaging.

To enhance the characteristics of the biocomposite film, solution cast was used to incorporate almond gum at different concentrations (10.0, 30.0, and 50.0%). The functional groups and morphology were determined using FTIR and SEM. The thermal property of chitosan and its composites materials were determined via TGA. In this study, the incorporation of almond gum into the chitosan matrix resulted in good mechanical strength, film thickness, and low barrier and solubility characteristics. Water vapor transmission rate (WVTR) and oxygen transmission rate (OTR) of the composites films was also investigated. The WVTR and OTR values for the chitosan/almond gum (CSA) composite film values are 11.6 ± 1.62 (g/m2/day) and 32.9 ± 1.95(cc/m2/24 h),respectively. The obtained composites show significantly improved antimicrobial activity against Gram-negative (E. coli) and Gram-positive (S. aureus) food-borne pathogenic bacteria. The results suggest that the CSA composites may serve as a promising candidate for antimicrobial food packaging materials. After an observation of the test results, it is inferred that the CSA composites bear good mechanical and antimicrobial activity and also show enhanced morphological characteristics.

Quality control of natural cork stoppers by image analysis and oxygen transmission rate

Abstract This work presents the evaluation of the porosity by image analysis, the quantitative analysis of the cell morphology from images obtained by scanning electron microscopy (SEM) and the oxygen transmission rate (OTR) of natural corks of different visual quality grades. Due to the natural variability of cork stoppers, statistically significant differences could not be established in the porosity of the corks according to their commercial quality. However, the determination of the surface porosity coefficient by image analysis in the tangential and axial sections of the corks allowed us to distinguish between high, medium and low quality classes. The cells in the tangential section were shaped between circular and hexagonal, with very regular perimeters regardless of the cork quality. While the cells of the radial and axial sections showed a square and rectangular shape, with more irregular perimeters, mainly in the lowest quality corks and in the axial section. Corks commercially classified as “flower”, “second” and “third” had the lowest OTR values and presented a similar statistical distribution in their cell perimeters in the axial section. While the corks with higher OTR values (superior and fourth qualities) corresponded with those with greater cell perimeters and greater dispersion in their distribution.

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

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.

Structure-Gas Barrier Property Relationship in a Novel Polyimide Containing Naphthalene and Amide Groups: Evaluation by Experiments and Simulations.

In order to meet the increasingly stringent requirements for heat resistance and barrier properties in the packaging and electronic device encapsulation field. A high-barrier polyimide (NAPPI) contains naphthalene ring and amide group was prepared by polymerization of a novel diamine (NAPDA) and pyromellitic dianhydride. The structure and properties of diamine monomers and polymers were characterized. Results show that the NAPPI exhibits superior barrier properties with extremely low water vapor and oxygen transmission rate values of 0.14 g·m−2·day−1 and 0.04 cm3·m−2·day−1, respectively. In addition, the NAPPI presents outstanding mechanical properties and thermal stability as well. This article attempts to explore the relationship between NAPPI structure and barrier properties by combining experiment and simulation. Studies on positron annihilation lifetime spectroscopy, Wide angle X-ray diffractograms and molecular dynamics simulations prove that the NAPPI has smaller interplanar spacing and higher chain regularity. In addition, the strong chain rigidity and interchain cohesion of NAPPI due to the presence of the rigid naphthalene ring and a large number of hydrogen bond interactions formed by amide groups result in compact chain packing and smaller free volume, which reduces the solubility and diffusibility of small molecules in the matrix. In general, the simulation results are consistent with the experimental results, which are important for understanding the barrier mechanism of NAPPI.

Oxygen Gas and UV Barrier Properties of Nano-ZnO-Coated PET and PHBHHx Materials Fabricated by Ultrasonic Spray-Coating Technique.

Ultrasonic spray-coating (USSC)—a wet chemical deposition method to deposit ultrathin (down to 20 nm) coatings—is being applied as a promising alternative deposition method for functional coatings due to an economical, simple, and precise coating process with easy control over its operating parameters. In this research, zinc oxide nanoparticles (ZnO NPs) were ultrasonically spray-coated on commercial-grade polyethylene terephthalate (PET) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) films. The most suitable parameters for the ink composition, the ultrasonic spray-coating process, and the number of coating passes (up to 50×) were selected on the basis of a series of experiments. The oxygen gas barrier properties in terms of the oxygen transmission rate (OTR) of neat PET, and 3×, 5×, 10×, and 50× ZnO NP-coated PET and PHBHHx substrates were investigated. The OTR values for neat PET, and 3×, 5×, and 10× ZnO NP-coated PET substrates were found to be the same; however, a 5% reduction in OTR for 50× ZnO NP-coated PET substrate was observed compared to the neat PET substrate. No reduction in OTR was found for any above number of coating passes on PHBHHx substrates against the neat PHBHHx substrate. However, the ultraviolet (UV) tests of 3×, 5×, and 10× ZnO NP-coated PET and PHBHH× substrates revealed a significant decrease in percentage transmission for 10× coated PET and PHBHHx substrates as compared to their 3× and 5× ZnO NP-coated substrates, respectively. It was revealed from the study that the 50× ZnO NP coating of the PET substrate created a slight difference in OTR as compared to the reference substrate. However, the ultrasonic spray-coating method created a significant UV barrier effect for 3×, 5×, and 10× ZnO NP-coated PET and PHBHHx substrates, which demonstrates that the optimized coating method cannot be used to create a high oxygen barrier but can certainly be applied for UV barrier applications in food packaging. It is concluded that ultrasonic spray deposition of ZnO NPs on PET and PHBHHx materials has shown promising results for UV barrier properties, demonstrating the advantages of using this method compared to other coating methods with regard to cost-effectiveness, precise coating, and better process control.

Aged layered double hydroxide nanosheet-polyvinyl alcohol dispersions for enhanced gas barrier coating performance.

Whilst applying a coating layer to a polymer film is a routine approach to enhance the gas barrier properties of the film, it is counter-intuitive to consider that the gas barrier performance of the film would improve by ageing the coating dispersion for weeks before application. Herein, we report that the oxygen barrier performance of a 12 μm PET film coated with a dispersion of inorganic nanosheets in polyvinyl alcohol can be significantly enhanced by ageing this coating dispersion for up to 8 weeks before application. We found up to a 37-fold decrease in the oxygen transmission rate (OTR) of the PET coated film using aged dispersions of [Mg0.66Al0.33(OH)2](NO3)0.33 layered double hydroxide nanosheets (Mg2Al-LDH NS) in polyvinyl alcohol (PVA) compared to the film coated with an equivalent freshly prepared LDH/PVA dispersion. A limiting OTR value of 0.31 cc m-2 day-1 was achieved using the PET film coated with a 3 week aged LDH NS/PVA dispersion. X-ray diffraction experiments show that the degree of in plane alignment of LDH NS on the PET film surface increased significantly from 70.6 ± 0.6 to 86.7 ± 0.6 (%) (100% represents complete alignment of LDH NS platelets on the film surface) for the 4 week aged dispersion compared to the freshly prepared layer. We postulate that when the Mg2Al-LDH NS are aged in PVA the coiled PVA aggregates start to unwrap and attach onto the Mg2Al-LDH NS through hydrogen bonding and eventually form a hydrogen bonded ordered network that facilitates the alignment of nanosheet dispersions during the coating process. Our results suggest that the ageing of inorganic nanosheet dispersions in PVA or other potential hydrogen bonding adhesive systems could be a general approach to improve the alignment of the nanosheets on the polymer film surface once applied and thus improve their performance characteristics for barrier coating applications.

3D Photoinduced Spatiotemporal Resolution of Cellulose-Based Hydrogels for Fabrication of Biomedical Devices.

Rational spatiotemporal irradiation of cellulose-based hydrogels (carboxymethylcellulose (CMC), citric acid, and riboflavin) using a laser diode stereolithography 3D printer obtained architectures referred to as photodegradation addressable hydrogels (PAHs). Under irradiation, these PAHs engage in an unprecedented spatially resolved zonal swelling illustrating marked but controllable changes in swelling and thickness while concomitantly obtaining improved oxygen transmission rate values by 5 times. XPS, carboxyl content, and swelling data comparisons of hydrogel formulations show that photodegradation and ablation of the material occur, where hydroxyl sites of CMC are converted to aldehydes and ketones. XRD data show that the total number of crystalline aggregates in the material are lowered after photoablation. The spatially tuned (photoablated) hydrogel films can thus be shaped into a lens form. The energy required for the lens tuning process can be lowered up to 30 times by incorporation of riboflavin in the films. The method demonstrated here enables the processing of a material that is difficult to be machined or cast by popular contact lens making methods.

Study of antimicrobial and physicochemical properties of LDPE/propolis extruded films

In this study, blended films of low-density polyethylene (LDPE) and different concentrations of propolis (5, 10, 15, and 20% w/w) were prepared by the extrusion method, and their antimicrobial and mechanical properties were investigated. Antimicrobial effects of the LDPE/propolis blended films were studied against Staphylococcus aureus, Escherichia coli, Aspergillus niger, and Saccharomyces cerevisiae strains. The results indicated the inhibitory effects of these films against A. niger and S. cerevisiae, especially at propolis concentrations ≥ 15% w/w. The mechanical properties of the films such as tensile strength and elongation at break decreased with the addition of propolis, with the change in tensile strength being statistically significantly with respect to the control film (0% propolis). Incorporation of propolis into the LDPE films caused increased water vapor permeability and oxygen transmission rate (OTR) values compared with the control film. However, significant changes were only observed in the OTR values of the blended films containing 15 and 20% w/w propolis. Fourier transform infrared spectra, as well as thermal analysis data from thermal gravimetric analysis and differential scanning calorimetry, revealed that the addition of propolis (5–20% w/w) to the LDPE polymer matrix did not cause significant changes in chemical structure and certain mechanical properties. Field emission scanning electron microscopy images revealed that the morphological structures of the LDPE/propolis films were swollen and had island-like forms in comparison with the control, and this property progressed with rising propolis concentrations. These observations demonstrated the lack of strong interactions between LDPE and propolis.

Application of image analysis and artificial neural networks to the prediction in-line of OTR in oak wood planks for cooperage

Oxygen Transmission Rate (OTR) is an important property of the wood employed in cooperage because of its relationship with the characteristics attained by the wine during the aging process. Nevertheless, this property has not been considered in the barrel making process because the time and systems required for measuring it do not allow its integration into a production line. This article proposes a method to classify the staves that compose each barrel in order to be able to build low-OTR barrels and high-OTR ones depending on the OTRs of the oak staves with significantly different levels among them. This method uses eight anatomical and physical parameters of the wood, which could be measured with in-line non-destructive methods, and a multilayer perceptron artificial neural network (MLP-ANN) to estimate the toasted-staves OTR value. Finally, the staves are classified according to their estimated OTR in three groups: low-OTR, high-OTR and those in between as the third group. The proposed stave classification system makes it possible to build oak barrels with different OTRs. Thus barrels with high OTRs with an average wood OTR almost three times higher than those with low OTRs could be built.

Oxygen barrier, free volume and miscibility properties of fully bio-based polyamide 1010/poly(vinyl alcohol) blends

Fully bio-based polyamide 1010 (PA1010) was successfully melt-blended with poly (vinyl alcohol) (PVA03, PVA05, PVA08 and PVA14) to prepare PA1010xPVAzy blends. The PA1010xPVA03y, PA1010xPVA05y, PA1010xPVA08y and PA1010xPVA14y films demonstrated the lowest oxygen transmission rates (OTR), free volume fraction (Fv), mean volume of the free volume holes (Vf) and mean number of free volume holes per unit volume (I3) values, when the PVA concentration in each PA1010xPVAzy series reached a corresponding critical value of 22.5, 20, 17.5 and 12.5 wt%, respectively. OTR, Fv, Vf and I3 values obtained for the best PA101087.5PVA1412.5, PA101082.5PVA0817.5, PA101080PVA0520 and PA101077.5PVA032.25 films reduced gradually as the degree of polymerization of PVA reduced. The results of dynamical mechanical and other experimental characterizations demonstrated that PA1010 and PVA are compatible to some extent, when the PVA are ≤ the corresponding critical concentration. The significantly enhanced oxygen permeation resistance and free volume characteristics for optimal PA1010xPVAzy films is at least partly due to the improved hydrogen-bonded molecular interactions between PA1010 C=O groups and PVA O-H groups.

Organic-Inorganic Hybrid Planarization and Water Vapor Barrier Coatings on Cellulose Nanofibrils Substrates.

Cellulose nanofibrils (CNF) can be produced in the form of thin, transparent and flexible films. However, the permeability of such materials to oxygen and water vapor is very sensitive to moisture, which limits their potential for a variety of packaging and encapsulation applications. Diffusion barrier coatings were thus developed to reduce the access of water molecules to enzymatically pre-treated and carboxymethylated CNF substrates. The coatings were based on UV curable organic-inorganic hybrids with epoxy, tetraethylorthosilicate (TEOS) and 3-glycidoxypropyltrimethylenesilane (GPTS) precursors and additional vapor formed SiNx layers. A total of 14 monolayer and multilayer coatings with various thickness and hybrid composition were produced and analyzed. The water vapor transmission rate (WVTR) of the bilayer epoxy/CNF film was two times lower compared to that of uncoated CNF film. This was partly due to the water vapor permeability of the epoxy, a factor of two times lower than CNF. The epoxy coating improved the transparency of CNF, however it did not properly wet to the CNF surfaces and the interfacial adhesion was low. In contrast hybrid epoxy-silica coatings led to high adhesion levels owing to the formation of covalent interactions through condensation reactions with the OH-terminated CNF surface. The barrier and optical performance of hybrid coated CNF substrates was similar to that of CNF coated with pure epoxy. In addition, the hybrid coatings provided an excellent planarization effect, with roughness close to 1 nm, one to two orders of magnitude lower than that of the CNF substrates. The WVTR and oxygen transmission rate values of the hybrid coated CNF laminates were in the range 5–10 g/m2/day (at 38°C and 50% RH) and 3–6 cm3/m2/day/bar (at 23°C and 70% RH), respectively, which matches food and pharmaceutical packaging requirements. The permeability to water vapor of the hybrid coatings was moreover found to decrease with increasing the TEOS/GPTS ratio up to 30 wt% and then increase at higher ratio, and to be much lower for thinner coatings due to further UV-induced silanol condensation and faster evaporation of byproducts. The addition of a single 150 nm thick SiNx layer on the hybrid coated CNF improved its water vapor barrier performance by more than 680 times, with WVTR below the 0.02 g/m2/day detection limit.

Preparation of polyacrylic acid-grafted-acryloyl/hemicellulose (PAA-g-AH) hybrid films with high oxygen barrier performance

Developing high-performance oxygen barrier films using biomass-based materials is crucial for the development of green and sustainable society. Herein, we develop a strategy to synthesize polyacrylic acid-grafted-acryloyl/hemicellulose composites (PAA-g-AH) as film materials with excellent oxygen barrier property. The as-synthesized films were extensively characterized by Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), gel permeation chromatography (GPC), 1H nuclear magnetic resonance (1H NMR), mechanical test, light transmittance and oxygen transmission rate (OTR) measurement. All these testing results showed that the optimum film exhibit great oxygen barrier property with a low OTR value of 0.25 ± 0.01 cm3* μm/(m2*d*kPa), which was much lower than that of pure PAA film. Moreover, the hybrid films possess well mechanical strength, light transmittance and recycle usage properties. Experimental results indicated that the as-synthesized films have great potential applications in several fields as packaging materials, such as drug, food and electronic products.

Facile Preparation of Polyacrylic Acid-Bentonite Nanocomposite Inks for Gas Barrier Thin-Films with Ultrasonic Treatment

The facile fabrication of an organic-inorganic hybrid nanocomposite film was investigated for a cost-effective gas barrier coating. Highly stable PAA/bentonite nanoink dispersion was achieved with high power ultrasonication treatment. The bar-coated PAA/bentonite film on PET substrate showed high barrier performance of oxygen transmission rate (OTR) value of 0.86 cc/m2·day at optimized nanoink concentration (5 wt%). In contrast, the OTR value was increased about 200 times with high ink concentraton (20 wt%). The detailed analysis of film morphology and microstructure revealed that the optimization of gas barrier properties have been achieved with proper clay platelet alignment and efficient water removal at interlayer. The gas barrier properties of one-step bar-coated barrier in this study provide industrially scalable simple gas barrier coating method for food and pharmaceutical packaging application.

Compatibility of banana starch nanocrystals/poly(butylene succinate) bio‐nanocomposite packaging films

ABSTRACTThis work focused on the effects of compatibility techniques [i.e., modification of filler and addition of an l‐lysine diisocyanate (LDI) coupling agent] and filler content on the properties of bio‐nanocomposite films prepared using poly(butylene succinate) (PBS) as a matrix and starch nanocrystals (SNC) as filler by chill‐roll cast film extrusion. The films reinforced with modified SNC had superior tensile and barrier properties than those reinforced with unmodified SNC or an added LDI. Elongation at break of 1%wt modified SNC/PBS film was increased up to 51.1% compared with neat PBS film. Water vapor transmission rate and oxygen transmission rate values of 9%wt modified SNC/PBS film (54.1 g m−2 day and 216.3 cc m−2 day) were lower than those of neat PBS film (114.5 g m−2 day and 560.3 cc m−2 day) due to the higher hydrophobicity and better dispersion of modified SNC in PBS leading to the superior properties of PBS films. The PBS bio‐nanocomposite films can be completely degraded within ~3 months under wastewater treatment condition. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46836.