The composite double-layered films, for the packaging application of postharvest fruits and vegetables, were prepared by laminating low-density polyethylene (LDPE) and poly[styrene-b-(ethylene-co-butylene)-bstyrene] (SEBS) modified with zeolite ZSM-5. The film was characterized by scanning electron microscope and differential scanning calorimeter and tested for permeation of ethylene (C 2 H 4 ), oxygen (O 2 ), carbon dioxide (CO 2 ), and water vapor. It was found that the C 2 H 4 permeability of the films was improved because of an enhanced adsorption of C 2 H 4 by the incorporated zeolite (0-10 wt%). The preconcentrated layer (zeolite/ SEBS) leads to a higher C 2 H 4 concentration gradient across the film. Moreover, the high dispersion of zeolite increased the C 2 H 4 permeation. When compared with O 2 and CO 2 , the composite films were more selective to C 2 H 4 . However, the C 2 H 4 permeation decreased in the presence of O 2 because of a competitive adsorption. In addition, the films possessed appreciate tensile properties for packaging application.
People are becoming more aware of plastic pollution. Consumers, researchers, and manufacturers are seeking ways to reduce their contribution to the problem. Management of plastic wastes has still been severely environmental problems, especially those with multilayer or multicomponent structures due to the difficulty in recycling process. According to the concept of circular economy, this research aimed to overcome these problems by recycling the multilayer plastic film wastes after use from consumers (classified as post-consumer recycled resin, PCR) and transforming those into high-value products. In this work, Wood Plastic Composites (WPCs) made from mixtures of multilayer packaging wastes (PCRs), recycled high density polyethylene (rHDPE) and wood powders were studied in order to be used as pallets in green industry. Studied factors affecting WPC properties included PCR types (linear low density polyethylene (LLDPE), multilayered oriented polyamide (OPA)/PE and polyethylene terephthalate (PET)/PE films) and rHDPE:PCR weight ratios (40:5, 35:10, 30:15 and 25:20). WPC samples were compounded by a two-roll mill and then shaped into samples by a compression molding machine. Morphological, mechanical and thermal properties of WPCs were examined. From SEM study, it was revealed that wood powders and fibers were well distributed and randomly oriented in WPCs. Both PCRs (OPA/PE and PET/PE) were partially melted because the processing temperatures were below the crystalline melting temperatures of OPA and PET. PCR orientation in WPCs was aligned with the compression direction. Mechanical properties of WPCs from OPA/PE were similar to those of WPCs from PET/PE. WPCs from rHDPE:PCR weight ratios of 40:5 and 35:10 had good mechanical properties which passed the industrial target values. Optimum formulas were then used to form WPC samples by extrusion technique and fabricated into WPC pallets. It was found that the WPC pallets from wastes showed promising properties with high potential to replace conventional pallets in warehouses and industrial transport for green industry.
The CO 2 and CH 4 permeabilities of poly(ethylene-co-vinyl acetate) (EVA)/ SiO 2 composite membrane were investigated at atmospheric pressure. The membranes were fabricated by compression molding and characterized by Fourier transformed infrared spectroscopy, differential scanning calorimetry, a universal testing machine, and a contact angle analyzer. The effect of vinyl acetate content (18-33 wt%) was evaluated for both single-gas and mixed-gas permeation systems. A non-pressurized homemade-permeation cell was used for the single-gas permeation of CO 2 and CH 4 , while a tubular membrane was utilized for a continuous separation of CO 2 /CH 4 mixture. CO 2 flux was readily increased (from 0.7 to 2.0 ml/m 2 .s) with vinyl acetate content (18-33 wt%). The enhanced CO 2 permeability is attributed to the increase in polarity and also the decrease in crystallinity of the membrane. A satisfied gas separation selectivity (CO 2 /CH 4 ) of 4.31 could be obtained from tubular membrane with 28 wt% VA content. The incorporation of SiO 2 as a filler (0.5-2.0 wt%) especially increased the membrane polarity and hence the CO 2 flux up to 6.0 ml/m 2 .s. However, the CH 4 flux was not affected by VA and SiO 2 contents.
In this work, water vapor permeability of linear low density polyethylene (LLDPE)/ethylene vinyl acetate copolymer (EVA) film is improved by incorporation of zeolite A as filler (0-25%wt) for prolonging shelf-life of fresh produces. All films were characterized by SEM, DSC, tensile testing, contact angle measurement and tested for water vapor permeability (WVP). The shelf-life of Bird’s eye chili in the film samples was also tested at 10°C for 21 days. It was found that zeolite A particles were virtually dispersed in EVA phase. Accordingly, crystallinity and tensile properties of LLDPE/EVA/Zeolite A films is independent to zeolite loading. Despite, when zeolite loading was increased, the dispersion became low. The film’s wetting behavior was enhanced by increasing zeolite content in the LLDPE/EVA/Zeolite A films. The observed increase in the film’s polarity significantly enhances the WVP. Therefore, less water condensed can be found inside the package made with LL80E20Ze25 film, as compared to LLDPE or LLDPE/EVA film. The LL80E20Ze25 also possesses comparable tensile properties to the commercial LLDPE film and hence can used as packaging for extending the shelf-life of fresh produces.
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