Nanocellulose has gained increasing attention during the past decade, which is related to its unique properties and wide application. In this paper, nanocellulose samples were produced via hydrolysis with ionic liquids (1-ethyl-3-methylimidazole acetate (EmimOAc) and 1-allyl-3-methylimidazolium chloride (AmimCl)) from microcrystalline celluloses (Avicel and Whatman) subjected to enzymatic pretreatment. The obtained material was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS), scanning electron microscopy (SEM), and thermogravimetric analysis (TG). The results showed that the nanocellulose had a regular and spherical structure with diameters of 30–40 nm and exhibited lower crystallinity and thermal stability than the material obtained after hydrolysis with Trichoderma reesei enzymes. However, the enzyme-pretreated Avicel had a particle size of about 200 nm and a cellulose II structure. A two-step process involving enzyme pretreatment and hydrolysis with ionic liquids resulted in the production of nanocellulose. Moreover, the particle size of nanocellulose and its structure depend on the ionic liquid used.

Lignocellulosic biomass, including that of energy crops, can be an alternative source to produce activated carbons (ACs). Miscanthus and switchgrass straw were used to produce ACs in a two-step process. Crushed plant material was carbonized at 600 °C and then obtained carbon was activated using NaOH or KOH at 750 °C. The content of surface oxygen groups was determined using Boehm’s method. The porosity of ACs was assayed using the nitrogen adsorption/desorption technique, while their thermal resistance using the thermogravimetric method. The ACs derived from miscanthus and switchgrass were characterized by surfaces rich in chemical groups and a highly developed porous structure. The highest specific surface areas, over 1600 m²/g, were obtained after carbon treatment with NaOH. High values of iodine number, 1200–1240 mg/g, indicate an extensive system of micropores and their good adsorption properties. The type of activator affected the contents of oxygen functional groups and some porosity parameters as well as thermal stability ranges of the ACs. Among obtained carbons, the highest quality was found for these derived from M. sacchariflorus followed by switchgrass, after activation with NaOH. Hence, while these crop species are not as effective biomass sources as other energy grasses, they can become valuable feedstocks for ACs.

The paper investigates the effect of surface modification of fumed nanosilica with (3-aminopropyl)triethoxysilane (APTES) on the kinetics and thermal stability of urea-formaldehyde (UF) resin. In the course of the investigation, nanoparticles were modified with APTES in the ratio 1, 2, 3, 4 and 5 part by weight (PBW) per 100 PBW of SiO₂. The parameters of curing kinetics of the resin, the conversion degree and its thermal stability were determined with use of differential scanning calorimetry (DSC) and thermogravimetric analysis (TG). The effect of nanosilica silanization on the curing process of resin was evaluated by determining the gel time at 100 °C and the activation energy (E_a) of the cross-linking process, the initial and final temperature of the reaction (T_onset, T_endset), the maximum value of the exothermic peak (T_p), the amount of emitted heat (ΔH_Tp) and the conversion degree (α_Tp) that responds to T_p. With the maximum level of silica modification, we have noted a decrease in the reactivity of the resin, which is manifested by a slightly longer gel time of the resin as well as an increase in the value of activation energy of the cross-linking process. It is accompanied by a slight decrease of resin conversion degree α_Tp. The modification of silica, regardless of the amount of silane inoculated on its surface, results in the increase in the thermal stability of UF resin.

The modern construction industry is looking for new ecological materials (available, cheap, recyclable) that can successfully replace materials that are not environmentally friendly. Fibers of natural origin are materials that can improve the properties of gypsum composites. This is an important issue because synthetic fibers (hardly biodegradable—glass or polypropylene fibers) are commonly used to reinforce gypsum boards. Increasing the state of knowledge regarding the possibility of replacing synthetic fibers with natural fibers is another step towards creating more environmentally friendly building materials and determining their characteristics. This paper investigates the possibility of manufacturing fiber–gypsum composites based on natural gypsum (building gypsum) and hemp (Cannabis sativa L.) fibers grown in Poland. The effect of introducing hemp fibers of different lengths and with varying proportions of mass (mass of gypsum to mass of fibers) into the gypsum matrix was investigated. The experimental data obtained indicate that adding hemp fibers to the gypsum matrix increases the static bending strength of the composites manufactured. The highest mechanical strength, at 4.19 N/mm², was observed in fiber–gypsum composites with 4% hemp fiber content at 50 mm in length. A similar trend of increased strength was observed in longitudinal tension. Again, the composite variant with 4% fiber content within the gypsum matrix had the highest mechanical strength. Manufacturing fibers–gypsum composites with more than 4% hemp fiber content negatively affected the composites’ strength. Mixing long (50 mm) hemp fibers with the gypsum matrix is technologically problematic, but tests have shown a positive effect on the mechanical properties of the refined composites. The article indicates the length and quantity limitations of hemp fibers on the basis of which fiber–gypsum composites were produced.

Novel carboxymethylcellulose (CMC) films with liquid products of pyrolysis (LPP) from wood pine were produced. The obtained CMC-LPP films were plasticized with 5% glycerol. CMC-LPP films were a light brown colour with a characteristic smoky scent, and showed a higher oxygen permeability when compared to control film without the addition of the LPP. CMC-LPP exhibited high antioxidant activity (5 and 18 times higher than CMC films). Furthermore, the antibacterial activity of the CMC-LPP films was tested, showing a strong inhibiting growth effect on the seven tested human pathogenic bacteria. The new material had the most substantial bacteriostatic effect on Listeria monocytogenes, Salmonella typhimurium, and Pseudomonas aeruginosa. Introduction of LPP to plasticised CMC produces an eco-friendly material with biocidal effect and favourable mechanical and structural properties, which shows its potential for possible use in many industries.

Forest biomass is a renewable source of environmentally friendly material—wood. However, wood processing generates large amounts of by-products, including branches. These byproducts are often used as firewood; however, they can be used much more effectively. In this study, the pyrolysis of two woods, namely birch and pine, was proposed. The liquid products of pyrolysis were studied by FTIR spectroscopy, and the heating value of these products was evaluated. In order to find the optimal pyrolysis temperature from the point of view of the calorific value of the product, the process was carried out at four temperatures: 450, 500, 550, and 600 °C. The liquid product yielded three fractions, from which two were analyzed, namely the dense tar fraction and light liquid fraction. FTIR analysis results clearly demonstrated that samples from different fractions differ from one another, yet the results within the same fraction are remarkably similar. The tar fraction was characterized with a higher gross calorific value between 42 to 50 MJ/kg, while the liquid fraction gross calorific value was between 29 and 39 MJ/kg; in general, pine wood yielded products with higher calorific values. The pyrolysis of small wood industry by-products is an interesting method of utilization, yielding not only a liquid product with good calorific properties, but also a solid product, namely biochar, which may be used in carbon storage or used as a soil amendment.