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Water-resistant chitosan and wey films
2000 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

Biodegradable films made of waste materials such as chitosan and whey are excellent oxygen barriers and thus potential packaging materials for foodstuffs. However, their poor moisture resistance make them unsuitable for liquefied foodstuffs and foodstuffs containing water. Studies of their moisture sensitivity have been carried out during recent years. The materials used to improve their moisture resistance are mainly native waxes and polymers. The aim of this diploma work was to improve the moisture resistance of chitosan and whey films by the application of a nitro-cellulose lacquer. Oxygen and water vapour permeability, water absorbency, folding and tensile properties and overall migration were measured on the coated films. The oxygen permeability was tested at 90% relative humidity and the results obtained were very good, in general better for chitosan films than for the whey films. A drying period of 3 weeks at 60*C for the films resulted in extremely low oxygen permeability. However, the drying reduced the flexibility of the films, especially for the whey films. Folding tests showed that the lacquer, too, was very brittle. The water vapour permeability was low for the coated films, which was confirmed by the absorbency test. It was observed during the tensile test that the adhesion between the lacquer layer and the chitosan matrix was weaker than the one between the lacquer and the whey. The overall migration showed results within the limit for materials in contact with foodstuff according to Normpack. However, neither of the films could withstand water for ten days.

Place, publisher, year, edition, pages
Keyword [en]
Technology, biodegradable films, native polymers, chitosan, whey, lacquer, water resistancy, oxygen barriers
Keyword [sv]
URN: urn:nbn:se:ltu:diva-59234ISRN: LTU-EX--00/324--SELocal ID: fc367a2e-8f12-457b-b6dc-090ebc93e955OAI: diva2:1032622
Subject / course
Student thesis, at least 30 credits
Educational program
Materials Engineering, master's level
Validerat; 20101217 (root)Available from: 2016-10-04 Created: 2016-10-04Bibliographically approved

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