Repository of University of Nova Gorica

Search the repository
A+ | A- | Help | SLO | ENG

Query: search in
search in
search in
search in
* old and bologna study programme

Options:
  Reset


1 - 2 / 2
First pagePrevious page1Next pageLast page
1.
Polysaccharide-based films and coatings for food packaging: A review.
Patricia Cazón, Gonzalo Velazquez, Jose A. Ramirez, Manuel Vazquez, 2017, review article

Abstract: The accumulation of synthetic plastics, mainly from food packaging, is causing a serious environmental problem. It is driving research efforts to the development of biodegradable films and coatings. The biopolymers used as raw material to prepare biodegradable films should be renewable, abundant and low-cost. In some cases, they can be obtained from wastes. This review summarizes the advances in polysaccharide-based films and coatings for food packaging. Among the materials studied to develop biodegradable packaging films and coatings are polysaccharides such as cellulose, chitosan, starch, pectin and alginate. These polysaccharides are able to form films and coatings with good barrier properties against the transport of gases such as oxygen and carbon dioxide. On the other hand, tensile strength and percentage of elongation are important mechanical properties. Desirable values of them are required to maintain the integrity of the packed food. The tensile strength values showed by polysaccharide-based films vary from each other, but some of them exhibit similar values to those observed in synthetic polymers values. For example, tensile strength values of films based on high amylose starch or chitosan are comparable to those values found in high-density polyethylene films. The values of percentage of elongation are the main concern, which are far from the desirable values found for synthetic polymers. Researchers are studying combinations of polysaccharides with other materials to improve the barrier and mechanical properties in order to obtain biopolymers that could replace synthetic polymers. Functional polymers with antimicrobial properties, as that the case of chitosan, are also being studied.
Keywords: Cellulose, Chitosan, Starch, Water vapour permeability, Tensile strength, Percentage of elongation at break
Published in RUNG: 14.12.2020; Views: 2666; Downloads: 0
This document has many files! More...

2.
Characterization of mechanical and barrier properties of bacterial cellulose, glycerol and polyvinyl alcohol (PVOH) composite films with eco-friendly UV-protective properties
Patricia Cazón, Gonzalo Velazquez, Manuel Vazquez, 2020, original scientific article

Abstract: Highly flexible composite films based on bacterial cellulose, glycerol and polyvinyl alcohol (PVOH) with UV barrier properties were developed. The open nanoscale network of bacterial cellulose allowed to combine it with glycerol and polyvinyl alcohol by immersion. This procedure kept intact the bacterial cellulose structure. The interactions among bacterial cellulose, glycerol and PVOH were analyzed using scanning electron microscopy, infrared spectroscopy, thermogravimetry and differential scanning calorimetry. In general, the addition of PVOH reinforced the bacterial cellulose matrix, meanwhile glycerol showed a significant plasticizing effect. Formulations with PVOH and glycerol reached a maximum value of 49.89% of elongation and a good resistance to rupture of 13.78 MPa. The water vapour permeability ranged from 1.87·10−11 to 2.04·10−10 g/m s Pa. The UV-VIS spectral analysis showed that glycerol decreased the transmittance in the UV area and polyvinyl alcohol enhanced the transparency values of the samples in the VIS region. The transmittance in the UV-A, UV-B and UV- C areas for films based on bacterial cellulose with glycerol reached up to 5.59, 2.4 and 0.57%, respectively.
Keywords: Acetobacter xylinum, Tensile strength, Percentage of elongation at break, Young's modulus, Eco-friendly film
Published in RUNG: 14.12.2020; Views: 2448; Downloads: 0
This document has many files! More...

Search done in 0.01 sec.
Back to top