Bota, Josip (2017) Optimizacija svojstava premazane kartonske ambalaže s obzirom na oblikovanje = Optimisation of Coated Paperboard Packaging Properties According to Design. Dissertation (PhD) thesis. Grafički fakultet. [Mentor: Brozović, Maja].
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Abstract
U radu su istraženi utjecaji polikaprolaktona (PCL) kao biorazgradljivog polimernog premaza na kartonu u svrhu unapređenja svojstava ambalaže i tiska na recikliranom kartonu. Također, istražene su modifikacije premaza dodavanjem nanočestica aluminijevog oksida (Al2O3), silicijevog dioksida (SiO2) i cinkovog oksida (ZnO). Uzorci premaza pripremljeni su otapanjem PCL-a u etil-acetatu, a umješavanje nanočestica provedeno je homogenizatorom. Mjerna karta boja otisnuta je na GD2 kartonima različite gramature (230 g/m2, 280 g/m2, 350 g/m2). Kartoni su premazani ispitivanim PCL i PCL nanokompozitnim premazima u različitim debljinama (4 μm, 24 μm, 40 μm, 80 μm). Odabir optimalne koncentracije i debljine nanokompozitnih premaza definiran je analizom kolorimetrijskih rezultata mjerne karte boja. PCL premaz je nakon optimizacije modificiran dodavanjem Al2O3, SiO2 i ZnO nanočestica. Karakterizirana su kolorimetrijska, adhezijska, barijerna, termička i mehanička svojstva kao i degradacija premaza te svjetlostalnost otiska uzoraka kartona s PCL premazom. Uzorci su također karakterizirani FTIR i UV-Vis spektroskopijom. Određeni su parametri adhezije kako bi se istražila međusobna povezanost kartona i PCL nanokompozitnog premaza odnosno mogućnost njihova raslojavanja. Tijekom istraživanja razmatrana je kompatibilnost PCL polimera i nanočestica praćenjem morfologije određene SEM mikroskopom te određivanjem termičkih (TG analizom) i mehaničkih svojstva (prekidne čvrstoće, prekidnog istezanja, otpornost na: savijanje, obostrano savijanje, pucanje i otiranje) dvoslojnog ambalažnog materijala. Provedena su mehanička ispitivanja postojanosti različitih ambalažnih oblika (valjak, trostrana, četverostrana, peterostrana i šesterostrana prizma) na tlačno naprezanje. Dodane nanočestice različito su unaprijedile uzorke otisnutog kartona s PCL premazima: ZnO nanočestice dominantno su unaprijedile svjetlostalnost i smanjile propusnost na vodenu paru, nanočestice SiO2 najviše su poboljšale mehanička svojstva kartona i kartonskih oblika, dok su Al2O3 nanočestice uzrokovale najmanje promjene u boji tj. postigle najveći stupanj transparentnosti PCL nanokompozita. Kod ispitivanih oblika ustanovljeno je da ambalaže valjkastog oblika postižu najveći stupanj strukturalne stabilnosti na na tlačno naprezanje, a oblik šesterokutne prizme utvrđen je kao optimalan s obzirom na odnos strukturalne stabilnosti i uštedu prostora pri transportu.
| Item Type: | Dissertation (PhD) thesis |
|---|---|
| Mentor name: | Brozović, Maja |
| Other mentors: | Hrnjak-Murgić, Zlata |
| Thesis Committee: | Milčić, Diana and Pibernik, Jesenka and Kratofil Krehula, Ljerka |
| Defence date: | 16 January 2017 |
| Abstract in english: | Packaging paperboards are exposed to increased mechanical stress and deformations during production and the use of packaging. This is a big issue when paperboards with a large amount of non selected recycled cellulose material are used because recycled paperboards have greatly decreased mechanical properties. Selection of packaging material has different requirements depending on the type of the product. Despite having numerous advantages; like strength to mass ratio, excellent printability, biodegradability and easy recycling, cellulose packaging has a large disadvantage due to its permeability. This characteristic is usually compensated by laminating or impregnating the paperboard using non-biodegradable polymers which can complicate the recycling procedure. In this study, polycaprolactone (PCL) was used in order to enhance properties of recycled paperboard. PCL is a biopolymer which has good permeability properties but lacks in tensile strength and transparency. In order to achieve the desired properties, PCL was modified with aluminum oxide (Al2O3), silicon dioxide (SiO2) and zinc oxide (ZnO) nanoparticles. The coating was prepared by dissolving PCL in ethyl-acetate, and nanoparticles were added using a homogenizer. GD2 paperboard was offset printed with a color chart in order to investigate the color change induced by the coatings. The weight of paperboard samples were 230 g/m2, 280 g/m2 and 350 g/m2. The coating was applied using a machine coater in four different thicknesses: 4 μm, 24 μm, 40 μm and 80 μm. The study was divided into five main stages. The first stage investigated the optimal concentration of SiO2 nanoparticles in PCL coating needed to achieve the minimum color change of the print, and to determine optimal thickness of the coating film. The color change of the print coated with additional PCL nanocomposites (PCL-Al2O3, PCL-ZnO, PCLSiO2/Al2O3 and PCL-SiO2/ZnO) was determined in the second stage. The third stage explored the adhesion, barrier, thermal and mechanical properties of the paperboard samples coated with PCL nanocomposites. The samples were also characterized using SEM microscopy and FTIR and UV-Vis spectroscopy. Later, in the fourth stage, the paperboard samples were shaped into various packaging forms with the same share of the test material. The tested forms were: triangular, quadrilateral (with three variations in the pages), pentagonal and hexagonal prism, and cylinder. The packaging shapes were exposed to vertical pressure using the crush test method to determine their structural stability and the effect of different coatings on the mechanical properties. In the last, fifth stage, printed paperboard samples with PCLand PCL nanocomposite coatings were subjected to accelerated aging using a xenon lamp chamber. The samples were additionally studied using FTIR analysis to establish whether there was a change in the degradation properties of the PCL nanocomposites, and colorimetric results were used to determine the level of lightfastness in order to define if the coatings decreased the amount of color fading of print. Research conducted in this study determined that the implementation of nanoparticles in the polymer matrix improved PCL properties which, when applied, enhanced the properties of printed paperboard. Implemented nanoparticles differently improved the properties of PCL coated paperboards: ZnO nanoparticles predominantly improved lightfastness of print and enhanced the water vapor permeability, SiO2 nanoparticles improved mechanical properties of paperboards samples and packaging shapes, while Al2O3 nanoparticles enhanced the transparency of PCL and caused the least amount of color change. Crush test of packaging shapes found that the cylindrical shape achieved the highest degree of resistance to compressive stress, but the hexagonal prism was determined as optimal due to its material to volume ratio, degree of resistance to vertical pressure and optimal use of space during transportation. |
| Uncontrolled Keywords: | polikaprolakton (PCL), karton, nanokompozit, permeabilnost, svjetlostalnost otiska, ambalažni oblik |
| Keywords in english: | polycaprolactone (PCL), paperboard, nanocomposite, permeability, lightfastness print, packaging shapes |
| Subjects: | TECHNICAL SCIENCES > Graphic Technology |
| Institution: | Grafički fakultet |
| City: | Zagreb |
| Number of Pages: | 138 |
| Callnumber: | 621.798 BOT o |
| Inventory number: | 10184 |
| Depositing User: | Nina Jelača |
| Status: | Unpublished |
| Date Deposited: | 01 Mar 2017 09:17 |
| Last Modified: | 01 Mar 2017 09:17 |
| URI: | http://eprints.grf.unizg.hr/id/eprint/2671 |
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