Poli(vinil alkoholni) filmi z dodatkom nanofibrilirane celuloze in ekstrakta lesa bora

• Main Author: Keržič, Eli
• Other Authors: Oven, Primož
• Format: Bachelor Thesis
• Language: Slovenian
• Published: E. Keržič 2017
• Subjects: polivinil alkohol; nanofibrilirana celuloza; ekstraktivi; filmi; UV-Vis; HPLC; polyvinil alcohol; nanofibrillated cellulose; ekstractives; films; info:eu-repo/classification/udc/630*813.2; sami
• Online Access: https://repozitorij.uni-lj.si/IzpisGradiva.php?id=95679; https://repozitorij.uni-lj.si/Dokument.php?id=104309&dn=; https://plus.si.cobiss.net/opac7/bib/2811529?lang=sl

Cilj diplomske naloge je bila priprava filmov na osnovi polimera in dveh biokomponent. Polimer polivinil alkohol (PVA) naj bi služil kot osnovna matrica nanofibrilirana celuloza (NFC) kot ojačitev ter ekstrakt iz lesa bora, za izboljšanje odpornosti proti mikroorganizmom. Najprej smo pripravili vse tri komponente ločeno. Kot prvo smo izvedli ekstrakcijo po Soxhletu. Uporabili smo topili cikloheksan in etanol. Ekstrakte smo analizirali z gravimetrično metodo, UV-Vis spektrofotometrijo in s tekočinsko kromatografijo visoke ločljivosti (HPLC). Ekstrakti so vsebovali največ pinosilvin monometilnega etra ter nekoliko manj pinosilvina in nortrahelogenina. Cikloheksanski ekstrakti so vsebovali manj ekstraktivov kot etanolni. Analizi ekstraktov je sledilo koncentriranje ekstraktov z rotavapiranjem, liofilizacijavodne suspenzije NFC in priprava 10 % vodne raztopine PVA. Komponente kompozita smo v ustreznih razmerjih zmešali z magnetnim mešalom. Mešanico smo vlili v steklene petrijevke. Filmi so se 2 dni sušili na prostem, nato pa 3 tedne v sušilniku na 50 °C. Osušeni filmi se niso ločili od podlage, zato smo za mehanski test izbrali razenje površine. Dodatek NFC in z reagentom TEMPO modificirane NFC (T_NFC) je ohranil ali izboljšal mehanske lastnosti polimera PVA. Sami ekstraktivi so imeli negativen vpliv na trdoto filma, v kombinaciji z NFC pa pozitivnega. Rezultati raziskave so pokazali, da je najprimernejša sestava kompozita 98 % PVA, 1 % NFC ter 1 % ekstraktivov. The aim of this thesis was the preparation of a polymer and two biocomponets based films. Polyvinyl alcohol (PVA) polymer was meant to serve as a matrix basis, cellulosic nanofibriles (NFC) as a strenghtener and pine wood extract as a booster of resilience against microorganisms. We began with preparing all of the components. We first performed a Soxhlet extraction. We used cyclohexane and ethanol as solvents. We analysed the extracts with the gravimetric method, high performance liquid chromatography (HPLC) and UV-VIS spectrophotometry. The extracts had the highest content of pinosylvin monomethyl ether and a somewhat lower content of pinosylvin and nortrachelogenin. Those obtained by cyclohexane contained lesser amounts of extractives than those obtained by etanol. We followed up the extract analysis by rotavaping them, lyophilising the NFC and preparing the PVA water solution. We mixed the composite components using a magnetic mixer and poured the mix into glass petri dishes. The films were dried in the open for two days, followed by 3 weeks at 50 °C in a dryer. As the dried films could not be removed from the surface, we chose the mechanical test of surface scratching. The addition of NFC and with TEMPO reagent modified NFC (TEMPO NFC) preserved or improved the mechanical characteristics of the PVA polymer. The extractives alone had a negative effect on the film hardness, but a positive one when combined with NFC. The results of the study showed that the most suitable composition was the 98 % PVA, 1 % NFC and 1 % extractives based composite.