Since millions of tons of packaging material cannot be recycled in conventional ways, most of it ends up in landfills or even dumped into the natural environment. The researched methods of chemical depolymerization therefore open a new perspective for the recycling of various PET materials, which are especially important for packaging. Food preservative packaging materials made from PET plastics are complex, and their wastes are often contaminated, so there are no sophisticated solutions for them in the recycling industry. After integrating the biopolymer chitosan, which is derived from natural chitin, as an active surface additive in PET materials, we discovered that it not only enriches the packaging material as a microbial inhibitor to reduce the bacteria Staphylococcus aureus and Escherichia coli, thus extending the shelf life of the contained food, but also enables economical chemical recycling by alkaline or neutral hydrolysis, which is an environmentally friendly process. Alkaline hydrolysis at a high temperature and pressure completely depolymerizes chitosan-coated PET packaging materials into pure terephthalic acid and charcoal. The products were characterized by Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and elemental analysis. The resulting reusable material represents raw materials in chemical, plastic, textile, and other industries, in addition to the antimicrobial function and recyclability itself.

The present work deals with the preparation of chemically and enzymatically eugenol-modified chitosan and its application as a green coating on viscose for the potential production of medical textiles. The elemental composition of chemically and enzymatically eugenol-modified chitosan was determined by attenuated total reflection Fourier transform infrared (ATR FT-IR) and proton nuclear magnetic resonance (¹H NMR) spectroscopy. Moreover, potentiometric titration was used to estimate the number of accessible amino groups. The chitosan–eugenol formulation possesses a high antioxidant capacity level, as shown by the high content of phenolic compounds analyzed by the following methods: (a) Folin–Ciocalteu; (b) reduction of Fe³⁺ ions; and (c) α, α-diphenyl-β-picrylhydrazyl (DPPH^•). Viscose coated with chitosan–eugenol formulations was evaluated by ATR FT-IR spectroscopy and Acid Orange VII spectrophotometric methods, the results of which demonstrated the successful deposition of these formulations on the fibers. Scanning electron microscopy showed the presence of the functional coating on the viscose. Finally, antimicrobial testing was performed to determine inhibition of selected pathogenic micro-organisms using the ASTM E 2149-01 standard. The antioxidant activity of the functionalized viscose was investigated spectrophotometrically by the DPPH^• method. It was found that the coatings of eugenol-modified chitosan impart antimicrobial activity to the viscose against Gram-positive and Gram-negative bacteria as well as fungi, and cause inhibition of free radicals by introducing an antioxidant character. The chemical and enzymatic modification of chitosan offers many opportunities for the incorporation of many natural active ingredients into the chitosan system, which provides a good basis for further work related to the functionalization of chitosan for sanitary and medical use.

In order to achieve effective antimicrobial protection of textile materials against microorganisms, a natural compound called chitosan has become very interesting. In regard to the antimicrobial protection of textile materials, functionalization with chitosan does not affect some other properties, such as antioxidative or any other action. For this reason, it seems appropriate for chitosan to be combined with any natural antimicrobial active compound, such as eugenol, an extract of clove oil. During this research viscose as a representative of cellulose fibers was used, because it can be functionalized relatively easily. In terms of functionalization, the drying temperature of viscose, after antimicrobial compound application onto substrate, as well as the successful synthesis of copolymer chitosan/eugenol is also important. FTIR spectroscopy was used to evaluate the efficiency of synthesizing a chitosan/eugenol graft copolymer. The spectrophotometric method Acid Orange 7 was chosen as a means for determining the proportion of available antimicrobial active amino groups. In addition, microbiological testing of selected pathogenic micro-organisms was also performed. The results were compared with the results for viscose functionalized by a 1% solution of chitosan.

Cotton sanitary towels were functionalized by probiotic paste with incorporated Lactobacillus L. fermentum LN99, L. rhamnosus LN113, and L. gasseri LN40 in order to reduce the possibility of infection or inflammation during menstruation and to develop a friendlier product. These towels were characterized through elemental composition using attenuated total reflectance Fourier transform infrared spectroscopy, determination of the pH of aqueous extract, water retention, capillary properties, determination of absorption capacity, and microbiological testing, to assess the antimicrobials’ function and stability of lactic bacteria paste as a coating for sanitary towels. The results of the used methods show that the physical–mechanical properties of towels functionalized by probiotic paste are not significantly different if compared to non-treated ones. Attenuated total reflectance Fourier transform infrared spectroscopy set the successful functionalization of sanitary towels with probiotic paste due to the occurrence of typical probiotics paste peaks. The pH of the probiotic-functionalized sanitary towels was reduced in comparison to the reference material to an acidified region of pH = 5.6, which is an ideal environment for maintaining physiological pH. The decrease in water retention of towels after functionalization is relatively low (8.48 %). The sorption behavior of towels was worse by up to 15% regardless of the reference material, which is still acceptable from a practical point of view and internal standards of the included company Tosama d.o.o. The probiotic-functionalized sanitary towels absorb synthetic blood faster than the reference ones, due to compatibility of the paste with synthetic blood. Moreover, towels obtain functionalities such as good condition for lactobacilli growth with simultaneous pH adjusting, as well as introducing of Staphylococcus aureus reduction. Functionalization of sanitary towels with probiotic paste showed a commercial potential to reduce the probability of infection during the menstruation cycle, as well as being a more customer-friendly product.

Interest in researching biopolymers from renewable resources has risen over recent decades. Biopolymers that are byproducts within industrial production processes are of special importance, thus there is no need for additional fertile soil for their production. During the production of thermo-mechanical pulp within the paper industry, galactoglucomannans (GGMs) are dominant hemicelluloses and are released in large quantities in the processing of water as a byproduct. In this research a new possibility was investigated for the application of GGM from spruce wood. The influence of GGM adsorption from aqueous solutions onto polyethyleneterephthalate (PET) fibers on their surface properties and hydrophilic/hydrophobic character was thoroughly analyzed. The adsorption process was analyzed and optimized using quartz crystal microbalance with a dissipation unit. Total organic carbon determination was applied for evaluating the success of GGM adsorption onto PET fabric samples. The hydrophilic/hydrophobic character of treated fabrics was evaluated by moisture sorption determination as well as by water adsorption determination using tensiometry and water contact angles determination using goniometry. The results showed that even small amounts of adsorbed GGM significantly increased the hydrophilicity of PET fabric samples. Moisture content within standard atmosphere was increased by about 100%, water adsorption by about 250% and water contact angles were decreased from 125° to immediate spreading when comparing non-treated PET fabric with a GGM-treated one. The presented research proved the hypothesis that GGM from spruce wood is potentially highly applicable for functionalization of synthetic textile materials in order to significantly increase their surface hydrophilic characteristics.

The aim of this study was to analyze binding of chitosan and chitosan nanoparticles onto cellulose via oxidized cellulose. The ability of chitosan and chitosan nanoparticles to be adsorbed onto surfaces was determined by the use of the XPS spectroscopy which provided information about chemical composition of the fiber surface. On the other hand, the gravimetric method was also used by which the amount of chitosan and chitosan nanoparticles bounded onto surface was calculated based on the difference in masses before and after functionalization. The most important was to study the influence of aldehyde groups on the stability of chitosan binding onto cellulose. Thus, desorption of chitosan/chitosan nanoparticles from the fiber surfaces was evaluated by the presence of total nitrogen (TN) in desorption bath as well as by polyelectrolyte titrations. Together with these two methods, desorption was evaluated also by gravimetric method, where the extent of desorption was evaluated on the basis of the differences in the masses of fibers before and after desorption. It is concluded that the chitosan and chitosan nanoparticles are more efficiently bounded onto oxidized cellulose in comparison with the non-oxidized (reference) ones. Despite the binding of the positively-charged amino groups with the negative groups of cellulose and consequently smaller amount of available/residual protonated amino groups that are responsible for bioactivity, such functionalized fibers are still specifically antimicrobial.