Kinetika zamreževanja melamin-urea-formaldehidne smole z dodatkom nanofibrilirane celuloze

Sitar, Matic (author), Poljanšek, Ida (mentor)

V tem magistrskem delu smo z diferenčno dinamično kalorimetrijo spremljali utrjevanje melamin-urea-formaldehidne (MUF) smole z dodatkom treh različnih vrst nanoceluloze: z nanofibrilirano celulozo (NFC), TEMPO oksidirano NFC (TNFC) in z lignoceluloznimi nanofibrilami (LCNF). Kot katalizator smo uporabili 40 % raztopino amonijevega sulfata. Vzorce smo zamreževali v 100 μl in 40 μl aluminijastih lončkih pri različnih hitrostih segrevanja. V nekaterih primerih smo dodali tudi različne koncentracije nanoceluloze. Ugotovili smo, da MUF smola bolje zamrežuje z nanofibrilirano celulozo (NFC) kot s TEMPO oksidirano NFC (TNFC). Ne glede na količino in vrsto dodane nanceluloze, smo pri MUF smoli s katalizatorjem beležili praktično identične temperature in čase začetka zamreževanj ter doseženih temperatur eksotermnega vrha (Tmaks). Lignocelulozne nanofibrile (LCNF) pa z izbranim katalizatorjem niso kazale eksotermnih signalov, zato jih nadalje z MUF smolo nismo zamreževali. Z infrardečo spektroskopijo FT-IR ni bilo mogoče ugotoviti razlik v intenziteti trakov med vzorci MUF, MUF/NFC in MUF/TNFC, saj so bili FT-IR spektri med seboj zelo podobni. Predpostavljamo, da je bila koncentracija metilen-etrskih in metilenskih mostičkov med MUF in NFC/TNFC za identifikacijo s to metodo prenizka.

• Language: Slovenian
• Keywords: MUF smola, nanoceluloza, kinetika, DSC
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: BF - Biotechnical Faculty
• Publisher: [M. Sitar]
• Year: 2020
• PID: 20.500.12556/RUL-120427
• UDC: 630*813
• COBISS.SI-ID: 29370627
• Publication date in RUL: 20.09.2020

Secondary language

• Language: English
• Title: Kinetics study of the melamine-urea-formaldehyde resin with the addition of nanofibrillated cellulose

Abstract

In this master thesis, the differential scanning calorimetry was used to investigate curing of the melamine-urea-formaldehyde (MUF) resin with the addition of three different types of nanocellulose: nanofibrillated cellulose (NFC), TEMPO-oxidized NFC (TNFC) and lignocellulose nanofibrils (LCNF). A 40% concentration of ammonium sulfate was used as catalyst. The samples were crosslinked in 100 μl and 40 μl aluminum pans at different heating rates. In addition, several different types and concentrations of nanocelluloses were added. We found that the MUF resin crosslinked to a greater extent with NFC than with TNFC. Regardless of the additive and the type of nanocellulose added, almost identical onset temperatures and times as well as the peak temperature (Tmax) reached were recorded with the MUF resin with catalyst. Lignocellulose nanofibrils (LCNF), however, did not show any exothermic signals with the selected catalyst, so that they were no longer used for crosslinking with the MUF resin. The cured samples were also tested by FT-IR infrared spectroscopy. We did not notice any differences in the FT-IR spectra between the MUF, MUF/NFC and MUF/TNFC samples. The concentration of methylene-ether and methylene bridges between MUF and NFC/TNFC seems to be too low for identification with this method.

• Keywords: MUF resin, nanocellulose, kinetics, DSC