The main purpose of the current research was to determine the chemical structure of typical lignocellulosic residues generated in wood processing industries, fruit and vine growing activities, and ...the maintenance of green areas. Four characteristic groups of samples, e.g. wood sawdust, bark, tree prunings and the lignified residues of fruits were analysed for the content of ash, lipophilic and hydrophilic extractives, cellulose, hemicellulose and lignin. Gravimetric methods were used for the analyses, and the purity of individual isolated fractions was monitored by FTIR spectroscopy. The highest quantity of ash and low molecular weight extractive compounds was determined in bark and tree prunings, while concentrations of cellulose and total carbohydrates were highest in sawdust samples. Lignified fruit residues and bark proved to be rich sources of lignin. Because of their diverse chemical composition, all of the examined materials are potential feedstocks for the production of platform chemicals and other specific products within biorefinery processes.
The heartwood of two European larch trees was examined for the content of hydrophilic extractives. Ethanol was used as a solvent for extractions of adequately pretreated samples, while gas ...chromatography with flame ionisation detection (GC-FID), gas chromatography coupled to mass spectrometry (GC-MS) and high performance size exclusion chromatography (HPLC-SEC) were applied for analyses. Different phenolic compounds, such as flavonoids and lignans were identified and quantitatively evaluated. The most abundant flavonoids were taxifolin and dihydrokaempferol, while the main lignan was secoisolariciresinol. Contents of flavonoids and lignans, measured at different stem heights, varied between 10.6 and 15.7 mg/g. At lower and medium heights flavonoids prevailed, while at upper stem positions the concentrations of lignans significantly increased. In addition, some trimeric and tetrameric phenolic structures were also detected. There was very little variation in the composition of hydrophilics between the two examined trees. The identified flavonoids and lignans are classified as very strong antioxidants.
The heartwood of two European larch trees was examined for the content of lipophilic extractives. Hexane was used as a solvent for extractions, while gas chromatography with flame ionisation ...detection and gas chromatography coupled to mass spectrometry were applied for analyses. Different lipophilic groups of compounds, such as fatty acids, resin acids, diterpenoids, sterols, steryl esters and triglycerides were identified and quantitatively evaluated as well as individual low molecular mass components. Distribution of heartwood lipophilics in relation to the trunk heights was also determined and their most likely biological function in wood tissues discussed. The content of hexane extract increased with stem height. Various fatty and resin acids as well as diterpenoid alcohols and sterols were characterized. The predominating lipophilic compounds identified were isopimaric acid and diterpenoid alcohol larixyl acetate. Their average concentrations in examined samples was between 2.0 and 2.5 mg/g. Higher molecular mass lipophilics, e.g. steryl esters and triglycerides, were also present with concentrations between 0.5 and 2.2 mg/g. Key words: European larch, heartwood, lipophilic extractives, chromatographic techniques U radu je prikazan rezultat istrazivanja lipofi lnih ekstraktivnih tvari u srzi dvaju stabala europskog arisa. Kao otapalo za ekstrakciju primijenjen je heksan, a plinska kromatografi ja s plameno-ionizacijskim detektorom i plinska kromatografi ja povezana s masenom spektrometrijom primijenjene su za kemijske analize. Razlicite lipofi lne grupe spojeva, kao masne kiseline, smolne kiseline, diterpenoidi, steroli, sterolni esteri i trigliceridi, identifi cirane su u uzorcima i kvantitativno su procijenjene. Takoder su identifi cirani i procijenjeni pojedini spojevi niskih molekularnih masa. Odredena je i raspodjela lipofi lnih tvari u srzi s obzirom na visinu stabala i objasnjena njihova najvjerojatnija bioloska uloga u drvnim tkivima. Sadrzaj ekstrakta heksana povecava se s visinom stabla. Razlicite masne i smolne kiseline, kao i diterpenoidni alkoholi i steroli, takoder su zastupljeni u srzi europskog arisa. Dominantni identifi cirani lipofi lni spojevi jesu isopimaricna kiselina i diterpenoidni alkohol. Njihove prosjecne koncentracije u ispitivanim uzorcima krecu se izmedu 2,0 i 2,5 mg/g. Lipofi lni spojevi vece molekularne mase, npr. sterolni esteri i trigliceridi, takoder su otkriveni u koncentracijama izmedu 0,5 i 2,2 mg/g. Kljucne rijeci: europski aris, srz, lipofi lni ekstraktivi, kromatografske tehnike
Typical wood tissues, such as stemwood, bark, branches, twigs and needles, of two very old European larch trees (Larix decidua Mill.) were examined for the content of macro and micro mineral ...substances. Elemental analysis, atomic absorption spectrophotometry (AAS) and ultraviolet/visible (UV/VIS) techniques were applied for quantitative determination of individual elements. The results indicated that both trees had almost identical mineral content. The highest contents of macro elements N, P, S, K and Mg as well as micro elements Ni, Fe, Al and Co were measured in needles, while Ca, Mn and Zn prevailed in bark. Concentrations of substances were the lowest in stemwood. Comparison with similar studies of foliar mineral distribution proved that both trees had good nutrient status, which corresponded to their condition. Keywords: European larch, micro and macro nutrients, AAS, elemental analysis, foliar mineral distribution U radu se prikazuju rezultati istrazivanja sadrzaja mikromineralnih i makromineralnih elemenata u tipicnomu drvnom tkivu dvaju stabala vrlo starih europskih arisa (Larix decidua Mill.) kao sto su stablo (deblo), kora, grane, grancice i iglice. Za kvantitativno odredivanje pojedinacnih elemenata primijenjene su elementarne analize, atomska apsorpcijska spektrofotometrija (AAS) i ultraljubicasta/vidljiva (UV/VIS) analiticka tehnika. Prema dobivenim rezultatima, svi su usporedivi uzorci oba drva imali prakticki jednak mineralni sastav. Najveci sadrzaj makroelemenata N, P, S, K i Mg, kao i mikroelemenata Ni, Fe, Al i Co, zastupljen je u iglicama, no Ca, Mn i Zn prevladavali su u kori. Najnize koncentracije mineralnih tvari izmjerene su u drvu stabla (debla). U usporedbi sa slicnim studijama raspodjele mineralnih tvari u iglicama, dokazano je da svi uzorci drva imaju primjeren sadrzaj tih tvari, sto odgovara njihovu zdravom stanju. Kljucne rijeci: europski aris (Larix decidua Mill.), sadrzaj mikromineralnih i makromineralnih tvari, atomska apsorpcijska spektrofotometrija, elementarna analiza
Beech sawdust was used as reinforcing component for the preparation of biocomposites with polyoxymethylene % POM and polylactic acid % PLA as polymer matrix. Materials with different portions of ...sawdust, e.g. 5, 10 and 15 wt. %, were prepared by using extrusion and injection techniques. Their mechanical (E modulus, flexural and tensile strength and strain) as well as thermal (melting point, glass transition) properties were determined. The results indicate that sawdust acts as reinforcement of the composites in the case of flexural stress and also tensile strength by POM matrix. Addition of sawdust to POM and PLA increases maximal temperature of biocomposite utilization. The main advantage of new materials is low density. Despite their brittleness they are convenient, low-cost alternatives to composites reinforced with glass fibres.
Seven fast-growing invasive plant species were harvested in Slovenia and tested for their valorisation potential in the pulp and paper industry with the aim of sustainable substitution of commercial ...cellulose fibres. Cellulose fiber materials were isolated by filtration after solubilizing extractives, lignin and hemicellulose in a kraft pulping process. The chemical structure was thoroughly studied, as well as the optical, morphological and mechanical properties. All examined species (
Ailanthus altissima
,
Fallopia bohemica
,
Fallopia japonica
,
Rhus typhina
,
Robinia pseudoacacia
,
Rudbeckia laciniata
and
Solidago canadensis
) contain relatively high amount of C6 polysaccharides (> 35%), have notable hemicellulose content (30–40%), low ash content (< 2%) and can be easily delignified, while manufactured natural fibers exhibit convenient morphology (fiber length 0.47–0.88 mm; width 14.4–20.9 μm), optical (ISO whiteness 19.0–36.0%) and mechanical characteristics (tensile index 18.0–58.0 Nm/g; tear index 0.8–4.1 mN m
2
/g; and burst index 0.5–2.4 kPa m
2
/g indices), which makes them applicable to sustainable paper production. The pulp yields varied between 34–44%, where both darker herbaceous and brighter woody fibers were morphologically comparable to typical hardwoods. According to the observed properties
Robinia pseudoacacia
and
Rudbeckia laciniata
seem to be superior raw material for commercial papermaking products. The ubiquitous invasive plants pose a huge potential for the circular economy, especially in terms of their cascade valorisation of biorefinery by the isolation and valorization of hemicellulose, sugars, and lignins into added-value aromatic and aliphatic building blocks. However, promising yield of cellulose fibers of decent morphology and mechanical properties are reported in this study.
We have studied properties of thin protective coating layers of Al2O3, grown by atomic layer deposition (ALD) technique on surfaces of cellulose fibrous materials, using scanning electron microscopy ...(SEM), scanning transmission microscopy (STEM), energy dispersive x-ray spectroscopy (EDS), high-resolution transmission microscopy (HR-TEM), x-ray diffraction (XRD) and thermal gravimetry (TGA). A minimum thickness of about 50nm was required to completely inhibit oxygen diffusion into the material and prevent self-ignition at elevated temperatures. No substantial differences were found in morphology or protection performance of Al2O3 coatings produced by thermal or plasma-enhanced ALD (PEALD) methods. However, PEALD technique has shown almost a double growth rate, while, at the same time, it was successfully applied at temperatures as low as 40°C without degrading quality of the coating.
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•(PE)ALD produces thin, conformal protective coatings of Al2O3 on cellulose fibres.•Al2O3 coating protects cellulose fibres from self-ignition at elevated temperatures.•The minimum thickness of an effective Al2O3 coating is 50nm.•Pyrolysis of a coated cellulose fibre results in a stable hollow structure of Al2O3.
The deinking of paper-based printed electronics is a growing concern regarding the increase of printed electronics products. The benefits of using paper-based substrates instead of polymer or ceramic ...for the single-use printed electrodes can contribute to sustainability goals. The use of invasive plant species for making paper substrates for printed electronics is a unique opportunity to have several environmental benefits. In this study, the recycling issue of these products through the use of the deinking technique was evaluated. Screen-printed electrodes printed on an invasive plant-based paper and commercial cardboard were deinked, and their optical, morphological, and silver residues in paper and corresponding water extract were analyzed. The invasive plant-based paper had higher silver content in the recycled paper sheets, which influenced the optical and surface resistivity and residue ink particle number. On the other hand, the surface-treated cardboard had lower silver particle content after deinking, but higher silver concentrations in the water extract. The results indicate that ink-paper surface and ink-fibre interaction and adhesion is vital in the ink silver particles binding during the deinking process.
We have studied properties of thin protective coating layers of Al2O3, grown by atomic layer deposition (ALD) technique on surfaces of cellulose fibrous materials, using scanning electron microscopy ...(SEM), scanning transmission microscopy (STEM), energy dispersive x-ray spectroscopy (EDS), high-resolution transmission microscopy (HR-TEM), x-ray diffraction (XRD) and thermal gravimetry (TGA). A minimum thickness of about 50 nm was required to completely inhibit oxygen diffusion into the material and prevent self-ignition at elevated temperatures. No substantial differences were found in morphology or protection performance of Al2O3 coatings produced by thermal or plasma-enhanced ALD (PEALD) methods. However, PEALD technique has shown almost a double growth rate, while, at the same time, it was successfully applied at temperatures as low as 40 °C without degrading quality of the coating.
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