20.500.12556/RUL-178998 Vpliv ultrazvočnega soniciranja na porazdelitev velikosti modificiranih nanoceluloznih in mikroceluloznih vlaken Effect of ultrasonic sonication on the size distribution of modified nanocellulose and microcellulose fibers Celuloza je najpogostejša organska spojina na Zemlji. Sestavljena je iz dolgih verig molekul glukoze, ki so med seboj povezane z β-1,4-glikozidnimi vezmi. Glede na način pridobivanja te verige tvorijo trdna mikrovlakna, nanovlakna oziroma nanokristale. Namen diplomskega dela je bil raziskati vpliv ultrazvočnega soniciranja na velikost in porazdelitev celuloznih vlaken. V diplomskem delu sem se osredotočila na primerjavo med kationsko in anionsko modificiranimi nanoceluloznimi in mikroceluloznimi vlakni. Vzorce različnih nanoceluloz sem pripravila kot 0,2 % vodne disperzije. Vpliv ultrazvočnega soniciranja sem določala na podlagi dveh različnih spremenljivk: spreminjala sem (i) amplitudo soniciranja v območju od 0 % do 100 % pri konstantnem času (1 min) in (ii) čas soniciranja v časovnem intervalu od 0 min do 10 min pri konstantni amplitudi (20 %). Pripravljene vzorce sem proučila na analizatorju velikosti in porazdelitve velikosti delcev Microtrac S3500 v disperznem mediju. Po končanem eksperimentalnem delu so rezultati pokazali, da je bil vpliv amplitude na velikost delcev različnih celuloznih vlaken večji kot vpliv časa soniciranja. Pri povečanju amplitude soniciranja CCNF- in CCMF-vlaken je bil viden trend zmanjševanja velikosti delcev. Zanimiv je bil vzorec TOCNF- celuloze, ki je imel znatno povečano velikost delcev pri 60 % amplitudi. Pri časovni odvisnosti soniciranja delcev ni prišlo do večjih sprememb v velikosti delcev. Cellulose is the most common organic compound on Earth. It consists of long chains of glucose molecules, which are interconnected by β-1,4-glycosidic bonds. Depending on how this chain is produced, they form solid microfibers, nanofibres or nanocrystals. The purpose of my work is to investigate the impact of ultrasonic sonication on the size and distribution of cellulose fibers. In experimental part, I was focusing on comparing cationic and anionically modified nanocellulose and microcellulose fibers. I prepared samples of different nanocellulose as 0.2% aqueous dispersion. I determined the influence of ultrasonic sonication based on two different variables: I varied (i) the sonication amplitude in the range from 0% to 100% at constant time (1 min) and (ii) the sonication time in a time interval from 0 min to 10 min at constant amplitude (20%). I studied the prepared samples on the Microtrac S3500 Particle Size and Particle Size Distribution Analyzer in the dispersed medium. After the experimental work was completed, the results showed that the effect of amplitude on the particle size of different cellulose fibers was greater than the effect of sonication time. An increasing trend of decreasing particle size was observed with increasing amplitude of sonication for CCNF and CCMF fibers. The pattern of TOCNF cellulose was interesting, as it showed a significantly increased particle size at 60% amplitude. There were no significant changes in particle size related to the time dependence of sonication. nanovlakenska celuloza mikrovlakenska celuloza soniciranje velikost delcev cellulose nanofibers cellulose microfibers sonication particle size true false false Slovenski jezik Angleški jezik Diplomsko delo/naloga 2026-02-03 07:30:11 2026-02-03 07:30:19 2026-02-12 14:12:56 0000-00-00 00:00:00 2026 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 25470 268293635 Gradisek_Nusa_-_Vpliv_ultrazvocnega_soniciranja_na_porazdelitev_velikosti_modificiranih_nanocelu.pdf Gradisek_Nusa_-_Vpliv_ultrazvocnega_soniciranja_na_porazdelitev_velikosti_modificiranih_nanocelu.pdf 1 2E9E5175E998DC2B3B13BBDA3E83D9C3 5f56f9993e222a46b55ba87050ad9b236bc51dd109f8de8403218081c30e01e4 bf9ea0b5-00c9-11f1-a1ba-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=227046 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0