The aim of this master thesis deals with the optimization of the preparation of thin hydrogel films based on polyvinyl alcohol (PVA) with the possibility of incorporating suitable additives (polyelectrolytes, plasticizers, etc.) into the structure of the prepared film to modify its properties. DEAE-Dextran hydrochloride and polyglutamic acid (PGA) were used as polyelectrolytes. The basic characterization of the properties was performed on modified films, which were compared with pure PVA films. The films were characterized by thickness, swelling ability, barrier properties, tensile properties, specific surface area, antimicrobial tests, and thermogravimetric analysis. The swelling ability of PVA/PGA films was very high, which may be a disadvantage for their use in the packaging industry. Swelling increases the amount of water in the matrix of the PVA film, what leads to a higher growth of microorganisms and to degradation of thin film. The water vapor transmission rate was greatly affected by the addition of a plasticizer. The small specific surface area of the films indicates a smooth surface that promotes good barrier properties. Films with the addition of a plasticizer showed relatively good mechanical properties. The values of tensile strength, elongation and elastic modulus were comparable to commercially available films such as polypropylene (PP) or polyethylene (PE). Based on all experiments, PVA, PVA/DEAEDextran films and their variants with the addition of glycerol as a plasticizer were evaluated as the best candidates for the use of these films as packaging materials. The follow-up work could be dealing with the optimization of PVA films for oxygen permeability. Furthermore, the possibilities of using these films in the packaging industry based on the relative humidity of the environment, could be defined as other interesting area of future research.
| Identifer | oai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:449328 |
| Date | January 2021 |
| Creators | Vacková, Barbora |
| Contributors | Pekař, Miloslav, Kalina, Michal |
| Publisher | Vysoké učení technické v Brně. Fakulta chemická |
| Source Sets | Czech ETDs |
| Language | Czech |
| Detected Language | English |
| Type | info:eu-repo/semantics/masterThesis |
| Rights | info:eu-repo/semantics/restrictedAccess |
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