Apsorpcija 15 postotne otopine etanola u poliolefinskim m ambalažnim materijalima

master's thesis

• Title (english): Absorption of 15 percent ethanol solution in polyolefin packaging materials
• Author: Amalija Špralja
• Mentor: Kata Galić (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Chemistry and Biochemistry); (Laboratory for Physical Chemistry and Corrosion); Zagreb
• Defense date and country: 2007-07-09, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Polimerni filmovi različito propuštaju molekule permeata što ovisi o njihovoj debljini, prisutnosti aditiva, strukturnoj građi, svojstvima permeata (oblik i veličina molekule), razlici tlakova i vanjskim uvjetima (npr. temperatura, vlaga). Važna je i otpornost polimernih materijala prema kemijskoj prirodi namirnice, pa se često koriste modelne otopine kao simulanti hrane, a uvjeti testiranja uzoraka ovise o uvjetima čuvanja upakiranih namirnica. U ovom radu ispitana je apsorpcija 15%-tne otopine etanola (modelne otopine), brzina prijenosa vodene pare na poliolefinskim folijama pri različitim temperaturama (40°C, 4°C i 23°C) koje simuliraju uvjete čuvanja upakiranih namirnica. Otopini etanola je izmjerena pH vrijednost i provodnost prije i tijekom izlaganja poliolefinskih materijala. Sva tri obrađena polimerna materijala, polietilen (PE), biaksijalno orijentirani koekstrudirani polipropilen (BOPPcoex) i biaksijalno orijentirani koekstrudirani metalizirani polipropilen (BOPPcoex.met.) međusobno pokazuju razlike u apsorpciji 15%-tne otopine etanola pri različitim temperaturama, najvjerojatnije kao posljedica različite kristaliničnosti polimera. Provodnost i pH vrijednosti se mijenjaju različito, ovisno o polimernom materijalu i temperaturi izlaganja, a brzina prijenosa vodene pare poprima gotovo linearan trend za sva tri polimerna materijala nakon jedanaestog dana izlaganja u otopini etanola.

Abstract (english)

Polymeric films have different permeability characteristics depending on its thickness, additive presence, molecular structure of polymers, permeate characteristics (shape and molecule size), pressure differences and external conditions (such as temperature, humidity). Polymeric materials resistance towards chemical nature of the foodstuffs is also important. For this purpose, model solutions are often used as food simulants in contact with polymeric materials, at specific test conditions similar to ones at real conditions. In this thesis absorption of 15% ethanol solution (model solution), water vapour transmission rate on polyolefin foils at 3 different temperatures (40°C, 4°C and 23°C) were investigated. Ethanol solution was analysed for pH and conductivity before and during poliolefine films exposure. Each investigated polymeric material, polyethylene (PE), biaxially-oriented polypropylene (BOPPcoex.) and biaxially-oriented coextruded metalized polypropylene (BOPPcoex.met.) has shown different absorption levels of 15% ethanol solution at given temperatures, most likely as a result of different polimer crystalinity. Conductivity and pH values differ depending on polimeric materials and temperature. Water vapor transmission rate shows linear change for each one of polimeric materials after 11 days in 15% ethanol solution.

• Keywords: apsorpcija; brzina prijenosa vodene pare; modelna otopina; pH; polietilen; polipropilen; provodnost
• Keywords (english): absorption; conductivity; model solution; pH; polyethylene; polypropylene; water vapour transmission rate
• Language: croatian
• URN:NBN: urn:nbn:hr:159:242369
• Study programme: Title: Food Technology; specializations in: Food Engineering; Course: Food Engineering; Study programme type: university; Study level: graduate; Academic / professional title: diplomirani inženjer prehrambene tehnologije; smjer prehrambeno inženjerstvo (diplomirani inženjer prehrambene tehnologije; smjer prehrambeno inženjerstvo)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-09-07 09:18:06