Karboksimetiliranje celuloze pridobljene iz kmetijskih ostankov

Hočevar, Jan (author), Iskra, Jernej (mentor)

Osredotočil sem se na uporabo tipične presežne biomase (mešana koruzna biomasa, koruzna stebla in oluščeni storži ter pšenična slama). To biomaso sem najprej okarakteriziral in določil vsebnost celuloze, lignina, hemiceluloze, ekstraktivov ter pepela. Zaradi visoke vsebnosti celuloze, ki je v omenjenih materialih znašala med 35 % in 44 %, sem te laboratorijsko delignificiral po alkalnem postopku z NaOH. Izolirani celulozni vlaknini sem določil mehanske, morfološke in druge lastnosti. V okviru procesa delignifikacije sem izvedel tudi optimizacijo in ugotavljal, kako čas izvajanja delignifikacije in količina NaOH v raztopini vplivata na mehanske, morfološke in druge lastnosti vlaken. Nato sem raziskal še pretvorbo izoliranih celuloznih vlaken v karboksimetil celulozo (CMC) po Williamsonovi sintezi etrov v različnih topilih in pod različnimi pogoji. Potek reakcije na izolirani celulozni vlaknini sem primerjal s potekom na komercialnih beljenih oziroma nebeljenih celuloznih vlaknih. Izolirana celulozna vlakna in modificirane produkte sem med drugim okarakteriziral tudi s pomočjo FTIR spektroskopije in optične ter vrstične elektronske (SEM) mikroskopije.

• Language: Slovenian
• Keywords: biomasa, delignifikacija, celulozna vlakna, Williamsonova sinteza etrov, karboksimetil celuloza
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2019
• PID: 20.500.12556/RUL-112751
• COBISS.SI-ID: 1538409411
• Publication date in RUL: 11.11.2019

Secondary language

• Language: English
• Title: Carboxymethylation of cellulose obtained from agricultural residues

Abstract

I have focused on typical examples of excess biomass (corn stover, corn stems and peeld cobs as well as wheat straw). Firstly, I characterized this biomass and determined the content of cellulose, lignin, hemicellulose, extractives and ash. Due to the relatively high portions of cellulose, which was between 35% and 44%, the materials were delignified by alkaline procedure using NaOH. I have determined mechanical, morphological and other properties of isolated cellulose fibers. I also performed the optimization of delignification process and studied how the time of delignification and content of NaOH in solution affect mechanical, morphological and other properties of fibers. Further I studied the conversion of isolated cellulose fibers into the carboxymethyl cellulose (CMC) through Williamson ether synthesis in various solvents and under different conditions. I compared results with commercial bleached and unbleached cellulose fibers. Isolated cellulose fibers and modified products were characterized by FTIR spectroscopy as well as optical and scanning electron (SEM) microscopy.

• Keywords: biomass, delignification, cellulose fibers, Williamson ether synthesis, carboxymethyl cellulose (CMC)