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The demand for eco-friendly packaging materials has urged researchers to look for alternatives to petroleum-based polymers. In this regard, paper-based products have turned out to be a promising choice; however, their weak resistance to water has limited their application. The use of various additives to enhance paper's moisture resistance is a common practice. However, considering the growing global agenda for sustainable development, the search for new bio-based paper additives has become increasingly important. This study investigated the potential synergistic impact of the addition of nanofibrillated cellulose (NFC) and chitosan additives (CHIT) to different fiber combinations to improve paper's properties, in particular, their wet strength. The efficacy of the additive application order was examined and was found to be crucial in achieving the desired outcomes. The results showed that incorporating CHIT after NFC enhanced the paper's tensile and burst indicators, as well as the paper stretch in the dry state, by 35–70%, 35–55%, and 20–35%, respectively. In addition, the tensile index and stretch in the wet state improved 9–13 times and 2.5–5.5 times over, respectively. The air permeability decreased 2.5–12 times over. These findings demonstrate that the sequential addition of the NFC and CHIT additives yield a greater enhancement of paper's properties than using each additive separately. [ABSTRACT FROM AUTHOR]

This study investigates the mycelial biomass production and chitosan extraction potential of various Basidiomycota strains, including Heterobasidion annosum, Phanerochaete chrysosporium, Pleurotus ostreatus, Trametes versicolor, and Lentinus lepideus. Both submerged fermentation (SF) and solid-state fermentation (SSF) methods were employed. The chitosan yield in basidiocarps of Pleurotus ostreatus, Agaricus bisporus, and Ganoderma applanatum was also evaluated as a reference material. The chitosan extracted from fungal cells was characterized using elemental analyses and FTIR spectroscopy. Among the cultivated strains, P. chrysosporium exhibited the highest mycelial biomass concentration in SF (1.03 g 100 mL–1) after 14 days, while T. versicolor achieved the highest biomass concentration in SSF (3.65 g 100 mL–1). The highest chitosan yield was obtained from the mycelium of P. chrysosporium (0.38%) and T. versicolor (0.37%) in shaken SF. Additionally, commercially cultivated A. bisporus demonstrated the highest chitosan yield in fungal fruiting bodies (1.7%). The extracted chitosan holds potential as a functional biopolymer additive for eco-friendly materials, serving as an alternative to synthetic wet and dry strength agents in packaging materials. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass (LCB)-based thermal insulation materials available in the market are more expensive than conventional ones and consist mainly of wood or agricultural bast fibers which are primarily used in construction and textile industries. Therefore, it is crucial to develop LCB-based thermal insulation materials from cheap and available raw materials. The study investigates new thermal insulation materials from locally available residues of annual plants like wheat straw, reeds and corn stalks. The treatment of raw materials was performed by mechanical crushing and defibration by steam explosion process. Optimization of thermal conductivity of the obtained loose-fill thermal insulation materials was investigated at different bulk density levels (30–45–60–75–90 kg m−3). The obtained thermal conductivity varies in range of 0.0401–0.0538 W m−1 K−1 depending on raw material, treatment mode and a target density. The changes of thermal conductivity depending on density were described by the second order polynomial models. In most cases, the optimal thermal conductivity was revealed for the materials with the density of 60 kg m−3. The obtained results suggest the adjustment of density to achieve an optimal thermal conductivity of LCB-based thermal insulation materials. The study also approves the suitability of used annual plants for further investigation towards sustainable LCB-based thermal insulation materials. [ABSTRACT FROM AUTHOR]

In this study, novel blends of mycelium biocomposites (MB) were developed. Various combinations of birch sawdust and hemp shives with birch bark (BB) and wheat bran (WB) additives were inoculated with basidiomycete Trametes versicolor to produce self-growing biomaterials. MB were characterized according to mycelial biomass increment in final samples, changes in chemical composition, elemental (C, H, N) analyses, granulometry of substrates, water-related and mechanical properties, as well as mold resistance and biodegradability. The mycelial biomass in manufactured MB increased by ~100% and ~50% in hemp and sawdust substrates, respectively. The lignocellulose ingredients during fungal growth were degraded as follows: cellulose up to 7% and 28% in sawdust and hemp substrates, respectively, and lignin in the range of 13% in both substrates. A larger granulometric fraction in hemp MB ensured higher strength property but weakened water absorption (600–880%) performance. Perspective MB combinations regarding strength performance were hemp/BB and pure hemp MB (σ10 0.19–0.20 MPa; E 2.9 MPa), as well as sawdust/WB combination (σ10 0.23 MPa; E 2.9 MPa). WB positively affected fungal biomass yield, but elevated water absorption ability. WB improved compressive strength in the sawdust samples but decreased it in the hemp samples. BB supplement reduced water absorption by more than 100% and increased the density of sawdust and hemp samples. All MB samples were susceptible to mold contamination after full water immersion, with identified fungal genera Rhizopus, Trichoderma and Achremonium. The MB exhibited high biodegradability after 12 weeks' exposure in compost, and are therefore competitive with non-biodegradable synthetic foam materials. [ABSTRACT FROM AUTHOR]

The study of converting grey alder (Alnus incana) chips and silver birch (Betula pendula) flakes - residues from plywood manufacture - into blow-in insulation material by steam explosion (SE) is reported. The SE was conducted at temperatures between 200 and 235°C, for 0-5 min at pressures between 16 and 32 MPa. The severity parameters (logR0) of the SE was calculated, from which logR0≈3.6 was the most appropriate for production of blow-in materials. Thermal conductivity of the obtained insulating material was found to be in the range of 0.053-0.057 W m-1·K-1. [ABSTRACT FROM AUTHOR]