Utjecaj strukture na barijerne karakteristike polimernih materijala za pakiranje hrane

doctoral thesis

• Title (english): Influence of structure on barrier characteristics of polymer materials for food packaging
• Author: Damir Klepac
• Mentor: Srećko Valić (mentor)
• Committee member: Vesna Lelas (predsjednik povjerenstva)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; Zagreb
• Defense date and country: 2012-04-18, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology
• Universal decimal classification (UDC): 678 - Industries based on macromolecular materials. Rubber industry. Plastics industry

Abstract

Cilj ove disertacije bio je ispitati utjecaj jednoosne mehaničke deformacije, γ-zračenja i ubrzanog termičkog starenja na propusnost kisika kroz polimerne filmove: linearni polietilen niske gustoće (PE-LLD) i lijevani polipropilen (PPcast). Strukturne promjene ispitivane su metodama razlikovne pretražne kalorimetrije (DSC), elektronske spinske rezonancije (ESR), spektroskopije pozitronske anihilacije (PALS) i Fourier transform infracrvene spektroskopije (FTIR). Utvrđeno je da navedeni čimbenici općenito smanjuju propusnost kisika kroz ispitivane filmove. Smanjenje propusnosti je rezultat promjena u stupnju kristaliničnosti, ukupnom slobodnom volumenu i gibljivosti lanaca polimera.

Abstract (english)

The aim of this thesis was to investigate the influence of uniaxial mechanical deformation, γ-irradiation and accelerated thermal aging on oxygen permeability through polymer films of linear low density polyethylene (PE-LLD) and cast polypropylene (PPcast). Structural changes were investigated by differential scanning calorimetry (DSC), electron spin resonance (ESR), positron annihilation spectroscopy (PALS) and Fourier transform infrared spectroscopy (FTIR). It was found that these factors generally decrease oxygen permeability in investigated films. The reduction of permeability results from changes in the degree of crystallinity, fractional free volume and polymer chain mobility.

• Keywords: deformacija; DSC; ESR; FTIR; gama zračenje; PALS; polietilen; polipropilen; propusnost kisika; termičko starenje
• Keywords (english): deformation; DSC; ESR; FTIR; gamma-irradiation; oxygen permeability; PALS; polyethylene; polypropylene; thermal aging
• Language: croatian
• URN:NBN: urn:nbn:hr:159:399619
• Promotion: 2012-09-30
• Study programme: Title: Food Technology; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti (doktor/doktorica znanosti)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2018-05-17 08:10:38