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Modification of Polyolefins and selected natural polymers for improved properties in food packaging applications

Jagadish, R. S. (2010) Modification of Polyolefins and selected natural polymers for improved properties in food packaging applications. PhD thesis, University of Mysore.

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Abstract

The proposed work is aimed at the modification of polyolefins and selected natural polymers for improved properties in food packaging applications. In polyolefins, low density polyethylene was modified by blending with vanillin, polypropylene was modified chemically with diisocyantes and PEO with starch. In natural polymers, chitosan was modified by blending with glycerol, PEO and by intercalation of nanoparticles. In addition, chitosan was chemically modified with aldehydes (vanillin and 4-hydroxybenzaldehyde). All the chemically modified and blended polymers were converted into films by extrusion methods/solvent casting to characterize their physico-mechanical, optical, barrier, thermal, morphological, food compatibility, antimicrobial and biodegradable properties. The characterization was done using modern facilities like FTIR, NMR, GC/MS, SEM, WAXS and modeling of moisture-sorption isotherms. Blending of vanillin with LDPE improved its gas barrier properties and grease resistance substantially. This film had potential for its aroma releasing capacity for fatty foods. Chemical modified PP films with diisocyanates were better in gas barrier and mechanical properties. The modified LDPE and PP films were also ascertained for their compatibility in food packaging applications. Glycerol added chitosan/PEO films showed improvement in its elongation significantly ensuring the flexibility along with improvement in transparency of the films. WAXS studies confirm the changes in the properties. Chitosan /PEO based films with high WVTR increased their potential for use in fresh produce. Moisture-sorption isotherm models such as Smith, Caurie, Bradley, and Oswin were found best fitted in the range of water activity from 0.11-0.86. Chemical modification of chitosan with aldehydes had improved its water barrier and tensile properties significantly. The modified films were also found with effective antimicrobial activity. Chitosan based nano composite films showed improved tensile strength and water barrier properties along with excellent antifungal properties. PEO/starch blended films have shown their potential use in the packaging of fresh produce to control moisture evaporation. Smith model was found to be the best fitted in the range of water activity from 0.11-0.86 of the films.

Item Type: Thesis (PhD)
Uncontrolled Keywords: natural polymers, food packaging
Subjects: 500 Natural Sciences and Mathematics > 04 Chemistry and Allied Sciences > 27 Polymer Chemistry
600 Technology > 08 Food technology > 06 Preservation and Storage > 06 Packaging
Divisions: Food Packaging Technology
Depositing User: Food Sci. & Technol. Information Services
Date Deposited: 14 May 2012 11:19
Last Modified: 14 May 2012 11:19
URI: http://ir.cftri.com/id/eprint/10748

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