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V prvem delu magistrskega dela sem raziskoval zamreževanje komercialne natrijeve soli karboksimetil celuloze z uporabo različnih zamreževalnih reagentov na osnovi naravnih dikarboksilnih kislin z različnimi dolžinami verig (citronska kislina, jantarna kislina in jabolčna kislina) ter 2,5-furandikarboksilne kisline, ki so sintetizirane iz biomase. Reakcije zamreževanja so bile izvedene pod različnimi pogoji (reakcijski čas in temperatura sušenja ter različna množinska razmerja med celuloznim derivatom in uporabljenim zamreževalnim reagentom). S pomočjo infrardeče spektroskopije in termogravimetrične analize so bili določeni najboljši pogoji zamreževanja, na podlagi katerih so bile reakcije zamreževanja celuloznega derivata prenesene na večjo skalo. Ugotovljeno je bilo, da so lastnosti hidrogelov odvisne od časa sušenja in koncentracije zamreževalnega reagenta. Hidrogel z najvišjo stopnjo absorpcije vode dobimo pri uporabi 10-odstotnega zamreževalnega reagenta. V tem primeru znaša stopnja absorpcije vode 54 %, kar je približno 10 % (m/m) več kot v primeru komercialnega hidrogela, ki je imel 45-odstotno stopnjo absorpcije vode. V drugem delu magistrskega dela sem študiral reakcije zamreževanja neposredno na nativni celulozni vlaknini. Primarno so bili pri reakcijah zamreževanja uporabljeni kislinski kloridi alifatskih karboksilnih kislin z različnimi dolžinami alifatskih verig (sukcinil, adipoil, suberoil in sebakoil diklorid). Na ta način je bil raziskan vpliv razdalje med posameznimi zamreženimi celuloznimi verigami na stopnjo absorpcije vode. Slednje je neposredno povezano tudi z velikostjo 3D-praznin, v katere se vežejo molekule vode. Reakcijski čas zamreževanja celuloze, temperatura zamreževanja in množinsko razmerje med celulozo in zamreževalnim reagentom so bili optimizirani. V nadaljevanju so bile reakcije zamreževanja izvedene tudi neposredno z dikarboksilnimi kislinami in ustreznimi anhidridi. Primerjal sem potek reakcij in lastnosti sintetiziranih hidrogelov pri uporabi različnih zamreževalnih reagentov. S pomočjo različnih analiznih tehnik je bil definiran optimalni zamreževalni reagent oziroma optimalni pogoji zamreževanja in reakcijo zamreževanja celulozne vlaknine sem prenesel na večje merilo. Rezultati so pokazali, da ima na lastnosti hidrogelov na osnovi celuloze največji vpliv množinsko razmerje med celulozo in uporabljenim zamreževalnim reagentom. V primeru nižjih količin zamreževalnih reagentov in posledično nižje stopnje zamreženja pride do izboljšanja absorpcijskih lastnosti napram absorpcijskim lastnostim celuloze. Zelo dobre absorpcijske lastnosti dosežemo v primeru, ko celulozo zamrežimo z nižjo množino zamreževalnega reagenta in jo nato še dodatno modificiramo s sukcinskim anhidridom. Delež vezane vode v tem primeru znaša okoli 44 % glede na maso suhega hidrogela, kar je primerljivo z lastnostmi komercialnega hidrogela. Najboljše absorpcijske lastnosti dosežemo v primeru modifikacije celuloze s sukcinsko kislino v mediju, sestavljenem iz N,N-dimetilacetamida in litijevega klorida. Pri omenjenem hidrogelu znaša stopnja absorpcije vode 70 %. The first part of my master's thesis investigates crosslinking syntheses of commercial carboxymethylcellulose sodium salt using different crosslinking reagents based on natural dicarboxylic acids of different chain length (citric acid, succinic acid, malic acid) and 2,5-furandicarboxylic acid as molecules from biomass. The crosslinking reactions were carried out under different conditions (reaction time and drying temperature as well as different molar ratios between the cellulose derivative and the crosslinking reagent). Infrared spectroscopy and thermogravimetric analysis were carried out to determine the best crosslinking conditions, and cellulose derivative crosslinking reactions were transferred to a larger scale. It was found that properties of hydrogels depended on drying time and concentration of the crosslinking reagent. The hydrogel with the highest water absorption rate is obtained when 10 wt % of the crosslinking reagent is used. In this case, the water absorption rate was 54%, which is approximately 10% more than that of the commercial hydrogel with a water absorption rate of 45%. In the second part of my master's thesis, crosslinking reactions directly on native cellulose fibers were studied. Primarily, acid chlorides of aliphatic carboxylic acids with different aliphatic chain lengths (succinyl-, adipoyl-, suberoyl- and sebacoyl-dichloride) were used to carry out the crosslinking reactions. In this way, the influence of the distance between individual cross-linked cellulose chains on the degree of water absorption was investigated. This is also directly related to the size of 3D spaces to which water molecules bind. The reaction time of cellulose crosslinking, the crosslinking temperature, and the ratio between cellulose and the crosslinking reagent were optimized. In addition, crosslinking reactions were also performed directly with dicarboxylic acids and anhydrides. Reactions and properties of the hydrogels synthesized using different crosslinking reagents were compared. Various analytical techniques were used to determine the optimal crosslinking reagent or optimal crosslinking conditions, and the crosslinking reaction of cellulose fibers was transferred to a larger scale. The results showed that the properties of cellulose-based hydrogels have the greatest influence on the mass ratio between cellulose and the crosslinking reagent used. With lower amounts of crosslinking reagents and consequently a lower degree of crosslinking, absorption properties, compared to those of cellulose, improve. The best absorption properties were achieved when cellulose was crosslinked with a lower amount of the crosslinking reagent and then additionally modified with succinic anhydride. In this case, the proportion of bound water was about 44%, based on the weight of the dry hydrogel, which is comparable to the properties of a commercial hydrogel. The best absorption properties are obtained when cellulose is modified with succinic acid in a medium comprising N,N-dimethylacetamide and lithium chloride. The hydrogel has a water absorption rate of 70%.

Pri izbiri plošč za toplotno izolacijo moramo biti pozorni na izolativne lastnosti in vpliv na ugodje samega uporabnika. Izbiramo lahko med umetnimi (mineralna volna, polistiren, poliuretan, penjeno steklo itd.) in naravnimi (lesna vlakna, pluta, kokosova vlakna, slama, celulozna vlakna itd.) toplotno izolacijskimi materiali. Celulozna vlakna se v večini primerov vgrajujejo po sistemu vpihovanja. Ker omenjeni sistem zahteva primerno tehnologijo, smo v nalogi raziskali možnosti drugačne uporabe celuloznih vlaken in sicer v obliki plošč. Izdelali smo 6 različnih plošč različnih debelin z različno gostoto. Izdelali smo plošče debeline med 4 mm in 150 mm ter gostoto 57 kg/m3 in 770 kg/m3. Ugotovili smo, da gostota in debelina značilno vplivata na toplotni prehod. Najboljše izolacijske lastnosti je imela plošča z najnižjo gostoto in največjo debelino, najslabše lastnosti pa plošče z visoko gostoto in majhno debelino In the selection of panels for thermal insulation we should take care to insulation properties and the impact on user comfort. We can choose between synthetic (mineral wool, polystyrene, polyurethane, foam glass, etc,) and natural (wood fibers, cork, coconut fiber, straw, cellulose fibers, etc,) thermal insulating materials. In most cases, cellulose fibers are installed with blowing technology. We wanted to determine the effect of thickness and density of cellulose boards made of cellulose fibers. We have produced a variety of 6 plates of different thicknesses between 4 mm and 150 mm and different density, between 57 kg /m3 and 770 kg/m3. We found that the density and thickness, typically affect the thermal transition. The best insulating properties had panel with the lowest density and a maximum thickness, while the worst results were revealed by panels with a high density and a small thickness

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. 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.

V diplomskem delu smo obravnavali vpliv notranje nege na tlačno trdnost betona visoke trdnosti. Betoni visoke trdnosti imajo višjo tlačno trdnost kot običajni betoni, zato lahko elementi iz omenjenih betonov, v primerjavi z elementi iz običajnega betona, enako obtežbo pri manjšem prečnem prerezu elementa. Ker pa visoko tlačno trdnost zagotavljamo predvsem z nizkim vodo-cementnim razmerjem, so ti betoni podvrženi večjemu krčenju in posledično razpokam. Deformacijo krčenja v zgodnjem obdobju lahko močno omilimo z notranjim negovanjem betona, s pomočjo notranjih rezervoarjev vode, kar pa lahko negativno vpliva na tlačno trdnost betona. Izvedli smo eksperimentalno raziskavo, v okviru katere smo testirali in analizirali vpliv različnih notranjih rezervoarje vode v betonih na velikost njihove tlačne trdnosti. Kot notranji rezervoar vode smo uporabili predhodno namočen naraven lahek agregat lehnjak, predhodno namočen umeten lahek agregat, s komercialnim imenom Liapor, predhodno namočena bazaltna vlakna, predhodno namočena celulozna vlakna. Notranje rezervoarje vode v beton vgradimo tako, da del običajnega agregata zamenjamo s predhodno namočenim medijem. Ugotovili smo, da je predhodno namočen lahek agregat, naraven in umeten, omogočil betonu višjo tlačno trdnost glede na primerjalni beton brez lahkega agregata, vgradnji predhodno namočenih bazaltnih in predhodno namočenih celuloznih vlaken pa sta na tlačno trdnost betona vplivali negativno. In this thesis the influence of internal curing on the compressive strength of high strength concrete was examined. Such concretes have much higher compressive strength than conventional concretes, so they can withstand the same load with a smaller cross-section of the element. However, since the high compressive strength is ensured primarily by the low water-cement ratio, these concretes are subject to greater shrinkage and consequently, cracks. Early shrinkage deformation can be greatly alleviated by the internal curing of the concrete, by means of internal water reservoirs, which in turn may adversely affect the compressive strength of the concrete. An experimental study was conducted in which the phenomenon of internal reservoirs in high strength concrete was tested and analyzed. As an internal water reservoir we used pre-soaked natural tufa aggregate, pre-soaked artificial lightweight Liapor aggregate, pre-soaked basalt fibers and pre-soaked cellulose fibers. Internal water reservoirs were placed in concrete by replacing part of a conventional unit with a pre-soaked medium. We found that pre-soaked lightweight aggregate, natural and artificial, gave concrete a higher compressive strength compared to non-lightweight aggregate concrete, and placement of pre-soaked basalt and presoaked cellulose fibers had a negative effect on the compressive strength of concrete.

Prispevek obravnava rezultate optimiranja zamreženja tkanin iz močno vite viskozne preje z brezformaldehidnim reagentom. Proučevali smo vpliv koncentracije brezformaldehidnega reagenta za zamreženje, katalizatorja in neionogenega sredstva za mehčanje na nekatere uporabne lastnosti apretirane viskozne preje. Spremljali smo naslednje veličine: stopnjo nabrekanja viskoznih vlaken, barve razlike, pretržno silo, pretržni raztezek in kot razgubanja. Z uporabo brezformaldehidnega reagenta za zamreženje smo dosegli znižanje stopnje nabrekanja viskoznih vlaken za 51,1 do 92,4 %, povečanje kota razgubanja za 60 do 145%, zmanjšanje pretržne sile za 49% do 65% in pretržnega raztezka za 31,6 do 37,6%. Postopek zamreženja ne povzroča zaznavnik barvnih razlik in obarvanih tkanin. The paper presents the results of optimizing cross-linking of fabrics made from highly twisted viscose yarn by using the nonformaldehyde reagents. The influence of the crosslinking reagent concentration, catalyst and nonionogenic softener on some applicability properties of the finished viscose fabric was investigated. The following parameters were monitored: the degree of swelling of viscose fibres, elongation at break and crease recovery angle, as well as the influence of the finishing process on the colour of viscose fabrics made from highly twisted yarn. By using the cross-linking non-formaldehyde reagent the degree of swelling of viscose fibres decreased by 51.1 - 92.4%, the crease recovery angle increased by 65 - 145%, the breaking force decreased by 49 - 65%, and the elongation at break decreased by 31.6 - 37.6 %. The crosslinking process did not cause any noticeable colour deviations on the dyed fabric.

V prispevku so predstavljeni rezultati optimiranja zamreženja tkanin iz močno vite viskozne preje z reagentom z nizko vsebnostjo formaldehida - metilirane dimetiloldihidroksietilen sečnine (DMDHEU). Proučevali smo vpliv koncentracije reagenta za zamreženje, katalizatorja in neionogenega sredstva za mehčanje na nekatere uporabne lastnosti apretirane viskozne tkanine. Spremljali smo naslednje veličine: stopnjo nabrekanja viskoznih vlaken, pretržno silo, pretržni raztezek in kot razgubanja, kakor tudi vpliv postopka apretiranja na barvo viskoznih tkanin iz močno vite preje. Z uporabo reagenta za zamreženje z nizko vsebnostjo formaldehida smo dosegli: znižanje stopnje nabrekanja viskoznih vlaken za 29,5 - 62,7 odstotka, povečanje kota razgubanja za 18,4 - 144,3 odstotka, znižanje pretržne sile (za 7,2 - 22,9 odstotka) in pretržnega raztezka (za 6,2 - 20,9 odstotka). Postopek zamreženja ne povzroča zaznavnih barvnih razlik na pobarvanih tkaninah. The results of mathematical-statistical method for optimizing cross-linking of fabrics made from hard twisted yarn by using a reagent with low formaldehyde content - methylated dimethyloldihydroxyethylene urea (DMDHEU) are presented in the paper. The influence of the concentration of a cross-linking reagent, catalyst and non-ionic softener on certain applicability properties of finished viscose fabric is investigated. The following parameters were monitored: the degree of viscose fibres swelling, the breaking force, the breaking elongation and the angle of decreasing, as well as the influence of the finishing process on the colour of viscose fabrics made from hard twisted yarn. By using a cross-linking reagent with low formaldehyde content the following has been obtained: the decrease of viscose fibres swelling by 29.5 % - 62.7 %, the increase of the angle of decreasing by 18.4 % - 144.3 %, the reduction of breaking force (by 7.2 % - 22.9 %) and the breaking elongation (by 6.2 % - 20.9 %). The process of cross-linking does not cause any noticeable colour deviations on dyed fabrics.

V nalogi je izvedena protimikrobna funkcionalizacija dveh vlaknotvornih polimerov (naravni polimer: celuloza, sintetični polimer: polietilentereftalat) ki se najpogosteje uporabljata v najnaprednejših panogah kot so embaliranje živilskih izdelkov, razvoj novih medicinskih in sanitetnih materialov, ter vsadkov, itd. Za funkcionalizacijo le-teh smo uporabili polisaharid hitozan in sicer absorbiran v obliki tankih površinskih slojev s katerimi vnašamo v vlakna nove funkcionalne skupine, ki so gonilna sila biološke aktivnosti. Zatorej je bistvenega pomena uporaba tehnik, ki omogočajo analizo površinske elementarne sestave funcionaliziranih materialov. Cilj diplomske naloge je tako preučevanje površin funkcionaliziranih materialov z uporabo spektroskopskih metod ATR-FTIR ter komplementarne Raman spektrofotometrije za kvalitativno analizo funkcionalnih skupin vlaken. Doslej se je obema tehnikama namenjalo premalo pozornosti in sta tako okviru diplomske naloge podrobno preučeni in optimirani za uporabo vlaknotvornih polimerov funkcionaliziranih s polisaharidi. Analize funkcionaliziranih PET folij so pokazale da se hitozan v obliki filma oprime nosilnega materiala le mehansko in/ali s fizikalno adsorpcijo, medtem ko pa na celuloznih vlaknih ni moč zaslediti hitozana. The thesis discusses the implementation of antibacterial functionalization of two fibre formation polymers (a natural polymer: cellulose, a synthetic polymer: polyethylene terephthalate) which are most commonly used in most advanced sectors, as packing food products, development of new medical materials and implants etc. Polysaccharides as chitosan was used for functionalization, namely in the form of thin surface layers with which new functional groups were integrated into the fibres, and they formed the engine of biological activity. Therefore it is of vital importance to use the techniques which enable the analysis of superficial elementary composition of functionalized materials. The purpose of my thesis is to examine surfaces of functionalized materials by using the spectroscopic method ATR-FTIR and complementary Raman spectrophotometrics for quality analysis of functional groups of fibres. Until now both tehniques have not received enough attation and therefore are examined in details in my thesis and streamlined for the use of fibre formation polymers which are functionalized by polysaccarides. The analysis of functionalized PET foils has shown that the chitosan film attaches to the underlying material only mechanically and/or by means of physical adsorpiton on the other hand, no chitosan can be detected on cellulose fibres.