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1.
Characterization of bacterial cellulose films combined with chitosan and polyvinyl alcohol: Evaluation of mechanical and barrier properties
Manuel Vazquez, Gonzalo Velazquez, Patricia Cazon, 2019, izvirni znanstveni članek

Opis: Bacterial cellulose (BC) produced by Komagataeibacter xylinus is a biomaterial with a unique three-dimensional structure. To improve the mechanical properties and reinforce the BC films, they were immersed in polyvinyl alcohol (0–4%) and chitosan (0–1%) baths. Moisture content, mechanical properties and water vapour perme- ability were measured to assess the effect of polyvinyl alcohol and chitosan. The morphology, optical, structural and thermal properties were evaluated by scanning electron microscopy, spectral analysis, thermogravimetry and differential scanning calorimetry. Results showed that moisture content was significantly affected by the chitosan presence. Tensile strength values in the 20.76–41.65 MPa range were similar to those of synthetic polymer films. Percentage of elongation ranged from 2.28 to 21.82% and Young's modulus ranged from 1043.88 to 2247.82 MPa. The water vapour permeability (1.47×10−11–3.40×10−11 g/m s Pa) decreased with the addition of polyvinyl alcohol. The developed films own UV light barrier properties and optimal visual appearance.
Najdeno v: ključnih besedah
Povzetek najdenega: ...(0–1%) baths. Moisture content, mechanical properties and water vapour perme- ability were measured to assess... ...Films, Bacterial cellulose, Water vapor permeability, Chitosan, Polyvinyl alcohol, UV protection...
Ključne besede: Films, Bacterial cellulose, Water vapor permeability, Chitosan, Polyvinyl alcohol, UV protection
Objavljeno: 14.12.2020; Ogledov: 704; Prenosov: 0
.pdf Polno besedilo (1,78 MB)
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2.
Novel composite films from regenerated cellulose-glycerol-polyvinyl alcohol: Mechanical and barrier properties
Manuel Vazquez, Gonzalo Velazquez, Patricia Cazon, 2019, izvirni znanstveni članek

Opis: Cellulose is considered as an alternative for the demand of biocompatible and environmentally friendly food packaging. The aim of this study was to evaluate a composite film from regenerated cellulose combined with polyvinyl alcohol. Glycerol was used as a plasticizer. Mathematical models were used to describe the effect of the film structure on the mechanical (tensile strength, percentage of elongation at break) and barrier properties (water vapour permeability, light-barrier properties and transparency). The morphology, structural and thermal properties were evaluated by spectral analysis (FT-IR and UV-VIS-NIR), scanning electron microscopy and dif- ferential scanning calorimetry. Models predict cellulose-glycerol-polyvinyl alcohol films with tensile strength values from 25.9 to 369 MPa, similar to that of synthetic polymer films. The elongation at break of the developed films (0.89–18.7%) was lower than that of synthetic polymer films. The water vapour permeability obtained (2.32·10−11 - 3.01·10−11 g/s·m·Pa) was higher than that of petrochemical-based plastics. Cellulose films re- inforced with polyvinyl alcohol showed a smooth surface. Results showed that it is viable to accomplish com- posite films from cellulose-polyvinyl alcohol-glycerol with enhanced mechanical properties. The obtained films showed top values of transparency. The addition of glycerol resulted in films with a UV protective effect which could be important in food packaging to prevent lipid oxidative deterioration.
Najdeno v: ključnih besedah
Povzetek najdenega: ...of elongation at break) and barrier properties ( water vapour permeability, light-barrier properties and transparency). The... ...Regenerated cellulose, Tensile strength, Water vapor permeability, Anti-plasticizer, DSC, UV protection...
Ključne besede: Regenerated cellulose, Tensile strength, Water vapor permeability, Anti-plasticizer, DSC, UV protection
Objavljeno: 14.12.2020; Ogledov: 718; Prenosov: 0
.pdf Polno besedilo (727,71 KB)

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