Iranian Journal of Polymer Science and Technology 10163255 35 6 2023 02 20 Investigating the effect of graphene oxide nanosheets on the barrier properties of high density polyethylene coated by layer-by-layer assembly method Investigating the effect of graphene oxide nanosheets on the barrier properties of high density polyethylene coated by layer-by-layer assembly method 581 594 1965 10.22063/jipst.2023.3337.2215 FA Ehsan Sharghi Department of Plastics, Faculty of Processing, Iran Polymer and Petrochemical Institute, P.O. Box 14975-112, Tehran, Iran Parvin Ehsani Namin Department of Chemistry, Tehran North Branch, Islamic Azad University, P.O. Box 19585-936, Tehran, Iran Mahsa Javid Department of Plastics, Faculty of Processing, Iran Polymer and Petrochemical Institute, P.O. Box 14975-112, Tehran, Iran Ismaeil Ghasemi Department of Plastics, Faculty of Processing, Iran Polymer and Petrochemical Institute, P.O. Box 14975-112, Tehran, Iran Journal Article 2023 02 12 <strong>Hypothesis:</strong> A nanocomposite layer including graphene nanosheets could be used to enhance the barrier properties of high density polyethylene through a layer-by-layer assembly method. Planar graphene nanoparticles help to decrease the gas permeability of polyethylene substrates by making a tortuous pathway for gas molecules transmittance.<br /><strong>Methods</strong>: Two different methods were used to increase the barrier properties of high density polyethylene and the results were compared with each other. In the first method, a thin film of polymer nanocomposite including graphene oxide nanoparticles and polyvinyl alcohol was coated on the surface of high density polyethylene film using a film applicator. The effective variables in this method were the weight fraction of graphene oxide particles in polyvinyl alcohol and thickness of the nanocomposite layer. In the second method, a layer-by-layer assembly was used. Chitosan solution acted as a positive charge and graphene oxide suspension in water was utilized as a negative charge.<br /><strong>Findings</strong>: In high density polyethylene samples coated by polyvinyl alcohol nanocomposite (10 micrometers), the oxygen transmittance rate decreased drastically to 3 cm3m2 bar. This decrease was expected due to the structure of polyvinyl alcohol and its inherent barrier properties. By adding graphene oxide into polyvinyl alcohol, the permeability values showed a slight decrease and reached 0.8 cm3 m2 bar.<br />Statistical analysis based on the surface response method for the layer-by-layer method showed that permeability depends on pH, number of bilayers and graphene concentration. At high pH, the graphene oxide sheets take on a smoother and more stretched shape and are more likely to aggregate, which increases permeability.<br /><br /> <strong>Hypothesis:</strong> A nanocomposite layer including graphene nanosheets could be used to enhance the barrier properties of high density polyethylene through a layer-by-layer assembly method. Planar graphene nanoparticles help to decrease the gas permeability of polyethylene substrates by making a tortuous pathway for gas molecules transmittance.<br /><strong>Methods</strong>: Two different methods were used to increase the barrier properties of high density polyethylene and the results were compared with each other. In the first method, a thin film of polymer nanocomposite including graphene oxide nanoparticles and polyvinyl alcohol was coated on the surface of high density polyethylene film using a film applicator. The effective variables in this method were the weight fraction of graphene oxide particles in polyvinyl alcohol and thickness of the nanocomposite layer. In the second method, a layer-by-layer assembly was used. Chitosan solution acted as a positive charge and graphene oxide suspension in water was utilized as a negative charge.<br /><strong>Findings</strong>: In high density polyethylene samples coated by polyvinyl alcohol nanocomposite (10 micrometers), the oxygen transmittance rate decreased drastically to 3 cm3m2 bar. This decrease was expected due to the structure of polyvinyl alcohol and its inherent barrier properties. By adding graphene oxide into polyvinyl alcohol, the permeability values showed a slight decrease and reached 0.8 cm3 m2 bar.<br />Statistical analysis based on the surface response method for the layer-by-layer method showed that permeability depends on pH, number of bilayers and graphene concentration. At high pH, the graphene oxide sheets take on a smoother and more stretched shape and are more likely to aggregate, which increases permeability.<br /><br /> http://jips.ippi.ac.ir/article_1965_71eb5c1b50d8b38c949c952663ee359e.pdf