2391. Bacterial cellulose films: Evaluation of the water interactionPatricia Cazón, Gonzalo Velazquez, Manuel Vazquez, 2020, original scientific article Abstract: Bacterial cellulose is a biopolymer that is gaining attention due to its 3D structure, higher purity, porosity and surface area. However, this material can interact with water molecules from the surrounding environment, resulting in alterations of its properties. Hence, the purpose of this study was to analyze the modifications on the mechanical, water vapor permeability and optical properties of bacterial cellulose films as a function of the water activity. Results indicated that water acted as a plasticizer, mainly affecting mechanical and water vapor permeability properties. The moisture adsorption isotherms allowed predicting the moisture content of the bacterial cellulose films at several relative humidity conditions. Values for tensile strength and burst strength ranged from 15.50 to 22.28 MPa and from 145.03–338.10 g, respectively. The elongation and the distance to burst ranged from 1.36 to 3.71 % and from 0.39 to 1.86 mm, respectively. These values increased due to the plasticizing effect of the water molecules. Water vapor permeability values ranged from 1.35·10−12 to 3.13·10-11 g/ m s Pa, showing a significant increase up to 0.48 of water activity. Bacterial cellulose films showed excellent UV-barrier properties in the different water activities evaluated.
Keywords: GAB model, Moisture adsorption isotherms, Bacterial cellulose, Mechanical properties, UV-barrier properties
Published in RUNG: 09.12.2020; Views: 2536; Downloads: 0
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2392. UV-protecting films based on bacterial cellulose, glycerol and polyvinyl alcohol: effect of water activity on barrier, mechanical and optical propertiesPatricia Cazón, Gonzalo Velazquez, Manuel Vazquez, 2020, original scientific article Abstract: Biodegradable films based on bacterial cellulose, glycerol and polyvinyl alcohol are a new alternative to develop food packaging with the capac- ity to retard or inhibit the effect of UV radiation. However, these compounds are sensitive to moisture. Therefore, the purpose of this study was to evaluate the modifications of the mechanical, water vapor permeability and optical properties of these composite films depending on their water activity. Results showed that water molecules acted as a plasticizer
agent, modifying the mechanical, water vapor perme- ability and optical properties of the developed films. However, an overplastification process took place at higher activity water, resulting in a weakness of film structure and decreasing drastically the elongation. The transmittance in the UV–VIS light region decreased when the activity water increased. No significant variations were observed in color, trans- parency or opacity properties.
Keywords: GAB model, Moisture adsorption isotherms, Plasticization, Bacterial cellulose, Mechanical properties, UV-barrier properties
Published in RUNG: 09.12.2020; Views: 2467; Downloads: 91
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2393. Improving bacterial cellulose films by ex-situ and in-situ modifications: a reviewPatricia Cazón, Manuel Vazquez, 2021, review article Abstract: The high intake of plastic materials for food packaging causes environmental problems due to the nonbiodegradable properties of these materials. High, low and very low-density polyethylene, polyethylene terephthalate, polyvinyl chloride, polystyrene and polypropylene are the main materials used. Biodegradable
polymers from natural sources are potential raw materials to develop novel food packaging. Bacterial cellulose is a material with extraordinary properties that is gaining special interest for applications in the Food Industry. The excellent mechanical properties, thermal stability and barrier to water vapor, oxygen and UV radiation of bacterial cellulose compared to other polysaccharides make this material very attractive and a potential alternative to non-biodegradable synthetic materials. Nevertheless, bacterial cellulose films are limited due to their lower elasticity. Therefore, the aim of this review is to provide an overview of the ex-situ and in-situ modifications of bacterial cellulose to improve its properties for the development of films for food packaging.
Keywords: Bacterial cellulose, In-situ modifications, Ex-situ modifications, Food packaging.
Published in RUNG: 09.12.2020; Views: 2542; Downloads: 0
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2394. Hybrid research between Art and Science : podMAST2020, radio or television broadcast, podcast, interview, press conference Keywords: art thinking, artistic sensibility, born hybrid, collective filtering, video theory, transdisciplinary, organising research, research design, hybrid thinking, curatorship
Published in RUNG: 08.12.2020; Views: 2638; Downloads: 24
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2395. Creating better models of data work through big exercises of imagination2020, radio or television broadcast, podcast, interview, press conference Keywords: predictive economies, data, social tech, machine learning, autonomy, data worker, trade union, solidarity, labour extraction, data labour rights
Published in RUNG: 08.12.2020; Views: 2403; Downloads: 27
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2396. 20 years of Sajeta festival : respecting (non)human co-existence versus commercial expansion2020, radio or television broadcast, podcast, interview, press conference Keywords: programming, festivals, internationalisation, rural, urban, precarity, expanded music, intermedia
Published in RUNG: 08.12.2020; Views: 2498; Downloads: 21
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2397. Human and machine relationship needs (art for) a new corporeal hybridity2020, radio or television broadcast, podcast, interview, press conference Keywords: performance art, dancetheater, somatic, biopolitics, transdisciplinary, posthuman, embodiment, artistic research, bioart, robotics
Published in RUNG: 08.12.2020; Views: 2593; Downloads: 22
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2400. Designing new renewable nano-structured electrode and membrane materials for direct alkaline ethanol fuel cell : Conductivity mechanism information on cross-linked self-standing graphene-polysaccharide derivate membranes and their laminated composites with commercial synthetic membranesEgon Pavlica, Ahmed Kreta, Gvido Bratina, final research report Keywords: graphene, chitosan, polysaccharide, fuel cell, alkaline, ethanol, photoconductivity, ionic conductivity, mixed-conductor model
Published in RUNG: 03.12.2020; Views: 2600; Downloads: 0
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