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Cilj naše študije je bil razviti več različnih formulacij biokompozitnih in bionanokompozitnih filmov na osnovi polivinil alkohola (PVA) z dodatkom ojačitvene komponente – celuloznih nanofibril (CNF) in različnih tipov biološko aktivnih taninov – taninske kisline (TA), galne kisline (GA) in kostanjevega tanina (KT). CNF smo dodali v utežnem deležu 2 %; TA, GA in KT pa v utežnem deležu 4 % glede na PVA. S 4 % dodatkom TA v PVA matrico smo pripravili biokompozitni film, ki je izkazoval več kot 25 % višjo natezno trdnost v primerjavi z osnovnim PVA filmom. Z dodatkom 2 % CNF in 4 % TA v PVA matrico smo pridobili bionanokompozitni film (P2C4T) z izboljšanim modulom elastičnosti in natezno trdnostjo, hkrati pa smo z omenjenima dodatkoma povečali tudi fleksibilnost pripravljenega nanokompozita, saj je bila vrednost raztezka pri pretrgu za končni formulirani film (P2C4T) več kot 50 % višja od raztezka pri pretrgu za osnovni PVA film. Hidrofilnost površine dvokomponentnih PVA filmov je bila nižja, trikomponentnih pa višja.

Qualitative and quantitative analysis of wood plant extractives depend on the efficiency of the extraction method used. The aim of this study was the application of the accelerated solvent extraction system ASE 350 to obtain hydrophilic extracts form silver fir wood (Abies alba Mill.) and optimization of the extraction protocol. Silver fir trees originated from Kočevska Reka. Dissected and milled samples of sapwood, heartwood and knots were extracted with the ASE 350 with water, ethanol (95 % aq), acetone (95 % aq) and ethyl acetate. The number of extraction cycles was determined. Analysis of extracts was done by UV/Vis spectrophotometry and HPLC. The most effective solvent for the extraction of phenolic components from heartwood was ethanol (95 % aq), in the case of sapwood water and acetone (95 % aq) in the case of knotwood. Only two 5-minute extraction cycles were required for sufficient extraction yield when using ASE 350 at 100 °C and 103.42 bar.

The aim of the study was to prepare a bionanocomposite based on polylactic acid (PLA) with the addition of nanofibrillated cellulose (NFC) as a reinforcement component. For the production of the composite we used unmodified and acetylated NFC (A_NFC). Freeze-dried NFC was acetylated in a heterogeneous system with acetic anhydride in dimethylformamide (DMF) in the presence of pyridine as a catalyst. The success of the acetylation was determined by FT-IR spectroscopy. PLA films were prepared with the addition of 2.5%, 5% and 10% of unmodified and acetylated NFC. The focus of this research was the impact of the NFC additive on the transparency and on the resistance of the bionanocomposite to scratching. The transparency of the bionanocomposite film was measured using UV-Vis spectrophotometry, and the resistance of the films to scratching was evaluated with a scratch test. The optimal amount of NFC and A_NFC added to the polymer PLA to achieve better resistance of the bionanocomposite to scratching was determined. The best resistance of the prepared bionanocomposite to scratching was achieved by the addition of a 2.5% A_NFC to the PLA polymer, which also has minimal reduced transparency with respect to the PLA film. With the highest addition of A_NFC to the PLA polymer, bionanocomposite films with minimal reduction of transparency were obtained.