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The main goal of the investigation was to measure and estimate the thermal stability of pinosylvin, pinosylvin monomethyl ether, robinetin, and dihydrorobinetin, i.e., characteristic compounds of wood of Scots pine and black locust, respectively. The pure compounds were analyzed with chromatography before and after they were steam-sterilized and oven-dried. Detailed thermogravimetric analysis was followed to check the thermal decomposition of the stilbenes and flavonoids of wood. The tested phenolic compounds were susceptible to thermal degradation. After the steam-sterilization and oven drying, the amount of investigated phenolic extractives decreased by more than a half. The thermogravimetric analysis showed that stilbenes decompose differently than flavonoids, which can be attributed to the different chemical structures. Twenty minutes of steam sterilization followed by 24 h of oven drying decreased the amount of phenolic compounds in the vials; however, after the applied thermal treatments, the stilbenes and robinetins stayed available in such quantities that they can still provide sufficient bioactivity. [ABSTRACT FROM AUTHOR]

The main goal of the study was to examine and compare the inhibition effect of knotwood extractives of Scots (Pinus sylvestris) and black pine (Pinus nigra) against the two white-rot fungi and two brown-rot fungi. Knotwood was extracted in a Soxhlet apparatus. Extracts were chemically analyzed, and the inhibitory effect of purified pinosylvins and crude hydrophilic extracts was tested against growth of the white-rot fungi Schizophyllum commune and Trametes versicolor and the brown-rot fungi Fibroporia vaillantii and Gloeophyllum trabeum with the in vitro antifungal assay. Knotwood of Scots pine and black pine contained comparable amounts of total extractives. Pinosylvin, pinosylvin monomethyl ether and nortrachelogenin were characteristic compounds in knotwood extracts of both pines. Scots pine knotwood contained larger amounts of pinosylvin than black pine. The ratio between pinosylvin monomethyl ether and pinosylvin was higher in black pine knotwood. Purified pinosylvins and crude hydrophilic extracts inhibited the growth of all the white-rot and brown-rot fungi tested. Pure pinosylvins better inhibited fungal growth than crude knotwood extracts, whereas the efficiency was not unambiguous and relates to fungi species. Crude hydrophilic extracts of Scots pine more efficiently inhibited fungal growth than extracts of black pine. With the present investigation, hydrophilic extracts of pine knotwood were demonstrated as formulations of natural compounds with good antifungal properties. Broken tops of Scots pine, which can lie on forest grounds for a month or even more, still contain high amounts of phenolic extractives and are therefore a potential raw material for recovery of bioactive compounds. [ABSTRACT FROM AUTHOR]

Drug release profiles of novel alkane-crosslinked nanocellulose hydrogels were investigated. The common antiseptic compound chlorhexidine digluconate (CHX-DG) was loaded into the nanocellulose hydrogels, and the release kinetics were studied under two different release regimes. The hydrogels were effective at absorbing more than their dry weights of the antiseptic and retaining it during diffusion testing, with more than 60% of the drug retained in the hydrogels. Antimicrobial tests showed sustained antimicrobial activity of the CHX-DG-loaded hydrogels even after the two diffusion tests, which was attributable to non-ionic retention of the CHX-DG within the hydrogel structure. [ABSTRACT FROM AUTHOR]

The aim of the study was to find appropriate non-chlorinated solvent systems for the extraction and separation of pure pinosylvin (PS) and pinosylvin monomethylether (PSMME) from Scots pine/Norway spruce wood residues. The extraction was performed in a pressurized solvent extractor and the purification and isolation of pure substances was done by flash chromatography. More precisely, pure PS was isolated via sequential flash chromatography in two repetitions in the gradient mode of the mobile phase, with cylcohexane (CX) and ethylacetate (EtOAc), beginning with 100% CX and ending up with 100% EtOAc. The extractives were qualitatively and quantitatively analyzed in terms of PS and PSMME contents by gas chromatography-flame ionization detector (GC-FID), gas chromatography-mass spectrometry (GC-MS), high-performance liquid chromatography (HPLC) and proton nuclear magnetic resonance (1H-NMR) spectroscopy. [ABSTRACT FROM AUTHOR]

Freeze dried nanofibrils were acetylated in a heterogeneous system with acetic anhydride, pyridine, and dimethylformamide and the obtained acetylated cellulose nanofibrils (CNFac) were combined with poly(lactic acid) (PLA) to a composite. CNFac with its partially hydrophobic surface showed a good compatibility with PLA resulting in composite films with improved properties. Tensile strength (TS), modulus of elasticity (MOE), and elongation at break (EB) of PLA/CNF increased significantly when 2-5% of CNFac was added to the PLA matrix, while the addition of 10% and higher amounts CNFac decreased the EB at a higher TS and MOE. Mechanical parameters did not improve in the case of unmodified CNF addition. The addition of CNFac maintained transparency and had absorbance values between those of pure PLA film and PLA film with 2% CNF, while films formed with the addition of 5 and 10% of CNF were less transparent. The addition of CNF did not essentially affect the thermal properties of nanocomposite films. The addition of 2-10% of CNFac increased the enthalpy and maximal temperature of cold crystallization as opposed to higher loading of CNFac. The results of differential scanning calorimetry (DSC) coincide with those of the mechanical properties. Tailoring properties of PLA/CNF are only reproducible in case of homogenously distributed CNF within the PLA matrix and by an improved interphase adhesion between PLA and CNFac. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of different morphologies of solvent-exchanged (NFCSE), spray-dried (NFCSD), and freeze-dried (NFCFD) nano-fibrillated cellulose on the susceptibility to surface modification with the acetic anhydride/pyridine system. The degree of substitution (DS), morphology, degree of crystallinity (Icr), hydrophobicity, and thermal stability of acetylated products were examined. Acetylated NFCSD and NFCFD had higher DS than acetylated NFCSE, suggesting that drying pre-treatment increased the susceptibility of NFC for acetylation. The morphology of acetylated NFCFD and NFCSD with higher DS was different from unmodified samples, while that of NFCSE was not affected by acetylation. Microspheres of acetylated NFCSD started to dissolve when the highest DS was reached. As opposed to unmodified NFCFD, the nanofibrillar units of acetylated NFCFD became individualised at lower DS. Acetylated samples had lower Icr than the unmodified samples. A significant increase in the contact angle was observed at higher DS of acetylated NFC samples. Acetylation markedly elevated the thermal stability of the acetylated NFC samples. [ABSTRACT FROM AUTHOR]

Abstract: One-component polyurethane adhesives were prepared from difunctional linear polyether polyol and two types of isocyanates in order to achieve excellent adhesion to various substrates. The structure of the prepolymer was varied by using different stoichiometric excesses of isocyanate in the range between 5 and 24wt%. The simulation of synthesis between polyol and two isocyanates with 15wt% of the NCO groups was performed on a rheometer in order to determine the optimal reaction time. The average molecular weight, determined by GPC, and Brookfield viscosity of the prepolymers decreased with increasing amounts of free isocyanate (NCO) concentration. The structure of the prepolymers as well as the type and amount of side reactions as a function of the free NCO was determined by NMR analysis. The cross-linking, arising from allophanate linkages, was more pronounced at higher amounts of free NCO. Thermal properties of synthesized urethane prepolymers were investigated by DSC and TGA techniques. The glass transition temperatures (T g) of the prepolymers depend on the type of isocyanate used for the synthesis. Adhesion strength was also tested. Maximum tensile strength was observed at 15wt% of NCO for both series of prepolymers. [Copyright &y& Elsevier]

Abstract: The objective of this research was to investigate the effect of temperature, pressure, initiator concentration and agitation rate, in ethylene-vinyl acetate emulsion copolymerization, on copolymer composition. The inline React-IR ATR system was used to monitor the reaction as well as to determine residual free vinyl acetate. Pressure, temperature and agitation rate have great influence on mass transfer of ethylene monomer to the reaction sites. The vinyl acetate was introduced in semi-batch mode as well as ethylene since the copolymerization was carried out under a constant pressure of ethylene. The higher temperature results in lower content of ethylene incorporated in copolymer. Increase of pressure has a direct effect on the ethylene content in the copolymers through increasing solubilization of ethylene monomer which in turn increases ethylene content in the copolymers. Copolymers of up to 15wt.% of ethylene content have been synthesized at an ethylene pressure of 30bar and a temperature of 75°C. Analytical methods, such as differential scanning calorimetry, nuclear magnetic resonance, thermogravimetric analysis, and infrared spectroscopy were used for characterization of copolymers. [Copyright &y& Elsevier]

The objective of this research was to investigate the effect of liquefied wood (LW) on the cure kinetics and network properties of melamine-urea-formaldehyde (MUF) resins by differential scanning calorimetry. The MUF/LW compounds exhibited two distinct cross-linking processes. It can be assumed that there did not appear to be a coreaction of the MUF with the LW. The overall apparent activation energies ( E) of the curing reactions were calculated using the Kissinger equation. An nth-order kinetic model was used to describe the cross-linking of MUF/LW compounds, of various compositions, cured at different heating rates. The E values for the cross-linking process of the MUF/LW compounds predominantly tended to be approximately 80 and 71 kJ mol for MUF and LW, respectively. The apparent reaction orders of the MUF cross-linking process of the MUF/LW compounds were in the range 1-2, whereas the n values of the LW were approximately unity or less, which hints to there being a more complex mechanism of this process. [ABSTRACT FROM AUTHOR]

In this study we present the preparation of amphiphilic multiblock and diblock poly(L,L-lactide-co-L-aspartic acid) (PLAA) copolymers of different comonomer composition as well as the differences in their structural and molar mass characteristics. Multiblock PLAA copolymers were prepared by heating a mixture of L-aspartic acid and L,L-lactide in melt without additional catalysts, whereas the diblock PLAA copolymers were synthesized by copolymerization of the amino terminated poly(β-benzyl L-aspartate) homopolymer and L,L-lactide in THF/dioxane solution. The differences in structure, composition and molar mass characteristics of poly(L,L-lactide-co-L-aspartic acid) copolymers prepared according to the described synthetic procedures are discussed. The PLAA copolymers synthesized in melt are multiblock copolymers with partially branched structure, whereas those synthesized in solution are linear diblock copolymers with well defined length of both blocks. Both copolymers have comparable molar mass averages in the range of 103-104 g/mol, but they differ in molar mass distribution, which is narrower for diblock copolymers. [ABSTRACT FROM AUTHOR]

The main objective of our study was to investigate the possible differences in the chemical composition of extractives from the bark of silver fir (Abies alba) with respect to the location of the bark sample on the tree, viz. differences in extract composition between stem bark and branch bark samples. Extractives in the bark samples from branches, depending on the distance of the sample from the trunk, were also analysed, and the stem bark samples were analysed with respect to their inner and outer parts. The results of the chemical analysis of extractives were supported by information about their antifungal and antioxidant effects. After felling and sampling silver fir trees, the collected bark samples were ground and freeze-dried. Extraction of bark samples was followed by a system of accelerated extraction using only water as a solvent. The extracts were analysed chemically using gravimetry, spectrophotometry and chromatography. Free-radical-scavenging activity was measured using the DPPH method, and the antifungal effect towards three moulds and three wood-decaying fungi was investigated with antifungal assay using the agar well diffusion method. It was found that the moisture content in bark samples decreased intensively just after the bark samples were peeled off the stem. Detailed chromatographic analysis showed that the bark extracts contained 14 compounds, among which phenolic acids, flavonoids and lignans were found to be the characteristic ones. The content of hydrophilic extractives in the branch bark samples decreased with increasing distance of the sample location from the tree stem. The largest amounts of phenolic extractives were measured in stem bark, followed by branch bark sampled at the point at which the branch entered the tree. Analysis of the separated parts of the bark showed that the outer layers of stem bark contained larger amounts of phenolic extractives, as well catechin and epicatechin, compared to the inner layers. Concentrated extracts of branch bark showed the largest free-radical-scavenging activity among the investigated samples, while strong antifungal effects of the bark extract were not found. [ABSTRACT FROM AUTHOR]

Hydrogels are classified as a three-dimensional network system, capable of retaining large amounts of water while preserving their shape and dimensional stability. Due to their natural origin and biocompatibility with human tissue, cellulose nanofibrils are often considered to be promising candidates for bioactive hydrogels preparation. For such applications, their responsiveness under different types of mechanical load, including multiple cyclic compressions, is of crucial importance. In the present study, cellulose nanofibril-based hydrogels were initiated though a simple alkali neutralization treatment. Structural, rheological and compressive features were investigated as a function of elevated NaOH concentration and physical gelling conditions. It was found that a sufficiently concentrated alkaline solution allows the formation of mechanically robust cellulose nanofibril hydrogels, which can be dried to the state of ultralight material, aerogel, of low density (0.057 g cm −3), superior porosity (96.2%), super water absorbant capacity (1200%), and exceptional shear and compressive load resilience with elasticity modulus of 9.3 kPa. These outstanding characteristics can be predominantly attributed to the polymorphic conversion of cellulose I to cellulose II, which results from the mercerization of cellulose nanofibrils and creates a stable and firm hydrogels texture. [ABSTRACT FROM AUTHOR]

Bacterial cellulose (BC) film formation could be a critical issue in nanotechnology applications such as biomedical or smart materials products. In this research, purified pretreated BC was subjected to high intensity ultrasound (HIUS) and was investigated for the development of BC films. The morphological, structural and thermal properties of the obtained films were studied by using FE-SEM, AFM, FT-IR, XRD, TGA and DSC characterizations. Results showed that the most favorable purification treatment was the 0.01 M NaOH at 70 °C for 2 h under continuous stirring. The most suitable ultrasound operating conditions were found to be, 1 cm distance of ultrasonic probe from the bottom of the beaker, submerged in cold water bath cooling around 12 ± 2 °C. The power (25 W/cm²), time (30 min), BC concentration (0.1% w/w), amplitude (20 lm) and frequency (20 kHz) were maintained constant. [ABSTRACT FROM AUTHOR]

In this study, we modified melamine-formaldehyde (MF) resin adhesive with liquefied wood (LW) and determined the properties of MF–LW adhesive mixtures. Furthermore, we produced particleboards using prepared MF–LW mixtures and evaluated their mechanical and physical properties. Results showed that with increasing content of LW in the adhesive mixture gel time and peak temperature increased while reaction enthalpy decreased. With increasing substitution of MF resin adhesive with LW the thermal stability of adhesive mixture reduced, namely thermal degradation started at lower temperature and weight loss increased. Properties of particleboards improved with increasing amount of LW in the adhesive mixture up to 20% and then deteriorated. Nevertheless, the properties of particleboard with 30% LW in the adhesive mixture were comparable to the properties of particleboard without LW while they worsen at greater portion of LW. Consequently, MF resin adhesive with 30% LW substitution could be used to produce particleboards with suitable mechanical properties and reduced formaldehyde release content. [ABSTRACT FROM PUBLISHER]

Common beech (Fagus sylvatica) is one of the deciduous tree species characterized by the formation of a discolored red heart in the central part of the stem. The aim of this work was to review data in existing literature and to present original results on the extractives present in sapwood and the red heart of beech. Samples of sapwood and red heart were taken from freshly felled beech trees and extracted with a speed extractor. The content of lipophilic and hydrophilic extractives was determined gravimetrically and further evaluated by gas chromatography. The beech wood contained, on average, 1.04% lipophilic and 3.71% hydrophilic extractives. Even though the gravimetrically determined content of lipophilic extractives was comparable in the sapwood and the red heart, saturated fatty acids, fatty alcohols, and free sterols were dominant in the red heart. Sapwood contained a larger amount of total hydrophilic extractives. Mono- and oligosaccharides, sugar acids and alcohols, carboxylic acids, simple phenols, and flavonoids were identified as the prevailing hydrophilic solubles in sapwood, whereas the concentration of sugar alcohols was higher in the red heart. The composition and character of the extractives in the wood of red-hearted beech should be considered the relevant technological factor. [ABSTRACT FROM AUTHOR]

The chemical composition of extractives in the sapwood (SW), heartwood (HW), knotwood (KW), and branchwood (BW of silver fir (Abies alba Mill.) was analyzed, and their antifungal and antioxidant properties were studied. In addition, the variability of extractives content in a centripetal direction, i.e., from the periphery of the stem towards the pith, was investigated. The extracts were analyzed chemically with gravimetry, spectrophotometry, and chromatography. The antifungal and antioxidative properties of the extracts were evaluated by the agar well diffusion method and the diphenyl picrylhydrazyl radical scavenging method. Average amounts of hydrophilic extractives were higher in KW (up to 210.4 mg/g) and BW (148.6 mg/g) than in HW (34.1 mg/g) and SW (14.8 mg/g). Extractives identified included lignans (isolariciresinol, lariciresinol, secoisolariciresinol, pinoresinol, matairesinol) phenolic acids (homovanillic acid, coumaric acid, ferulic acid), and flavonoids epicatechin, taxifolin, quercetin). Secoisolariciresinol was confirmed to be the predominant compound in the KW (29.8 mg/g) and BW (37.6 mg/g) extracts. The largest amount of phenolic compounds was extracted from parts of knots (281.7 mg/g) embedded in the sapwood and from parts of branches (258.9 mg/g) adjacent to the stem. HW contained more lignans in its older sections. Hydrophilic extracts from knots and branches inhibited the growth of wood-decaying fungi and molds. KW and BW extracts were better free radical scavengers than HW extracts. The results of the biological activity tests suggest that the protective function of phenolic extracts in silver fir wood can also be explained by their antioxidative properties. The results of this study describe BW as a potential source of phenolic extractives in silver fir. [ABSTRACT FROM AUTHOR]

The influence of the preconditioning at different temperatures on the cure kinetics of melamine-urea-formaldehyde resins coated on stone wool was investigated under acidic conditions using differential scanning calorimetry and thermogravimetry. The higher pre-treatment temperature was applied, to which resin-coated stone wool was exposed, the lower was the mass loss during the experiment. Kinetic model parameters were determined in two different manners, with the parameters being independent of preconditioning temperature and dependent on the latter. The apparent orders of reaction were approximately two (all of them being within the range 0.96-2.33), which would imply that cross-linking predominantly proceeds via the bimolecular reaction of either melamine or urea and formaldehyde. Nonetheless, the apparent orders of reaction decreased as a function of preconditioning temperature. The apparent activation energies varied less with preconditioning temperature, assuming values between 64.2 and 78.5 kJ mol. The applicability of nth-order reaction kinetic models was consequently validated for two other dynamic thermal regimes. [ABSTRACT FROM AUTHOR]

Cellulose was treated in ethylene glycol with p-toluene sulfonic acid monohydrate as a catalyst at different temperatures. At the highest treatment temperature (150 °C) liquefaction of wood pulp cellulose was achieved and was dependant on cellulose polymerization degree (DP). Furthermore, the rate of amorphous cellulose weight loss was found to increase with cellulose degree of polymerization, while the rate of crystalline cellulose weight loss was reciprocal to the size of the crystallites. The cellulose degradation was studied by monitoring of the molecular mass decrease by size-exclusion chromatography. It was revealed that microcrystalline cellulose degrades via a 'quantum mode' mechanism, while the degradation of Whatman filter paper no 1. and cotton linters proceeded randomly and were partly dependent on the starting polymerization degree, crystallinity, and treatment temperature. The kinetics of cellulose degradation in heterogeneous media was described by means of a one-stage model, characterised by the consumption of glycosidic bonds in amorphous and crystalline cellulose regions until the levelling-off degree of polymerization is reached. [ABSTRACT FROM AUTHOR]

Abstract: The novel concept of a simultaneous, controlled release of a drug and a prodrug with different physico-chemical properties was applied in order to prolong the release period of antibiotics and estimate their high local concentrations, which are the necessary preconditions for the treatment of some chronic infection diseases. For this purpose poly(D,L-lactide-co-glycolide)/hydroxyapatite (PLGA/HAp) core–shell nanostructures were used as the carrier of clindamycin-base, as a drug, and clindamycin-2-phosphate, as a prodrug model. As a result, a two-step release was observed: the controlled release of the more soluble phosphate form and the sustained release of the less-soluble base form of clindamycin, resulting in a high overall concentration of the released drug during the period of 30 days in vitro. The HAp phase within the PLGA core–shells, applied as a drug carrier, delayed the process of the degradation of the polymer; however, the presence of the drug affected the process of degradation and this influence was the dominant factor in the control over the degradation of the polymer phase of PLGA/HAp and the consequent kinetics of the drug release. [ABSTRACT FROM AUTHOR]

Poly(vinyl alcohol) (PVA) biocomposite films reinforced with cellulose nanofibrils (CNF) and biologically active tannic acid (TA) were prepared. The influence of different concentrations of CNF and TA in the PVA polymer matrix was investigated in terms of mechanical properties, thermal properties and hydrophobicity improvement of the prepared films. The results showed that in all cases the addition of CNF and TA improved the values of tensile strength and elastic modulus. The PVA film with 10 % CNF exhibited a 30 % higher tensile strength, and the three-component PVA film with 2 % CNF and 10 % TA (P2C10T) exhibited a 40 % higher tensile strength compared to the neat PVA film. The thermal properties (T g , T onset) of the PVA biocomposite films were greatly improved, with a significant effect observed for the three-component PVA films. The T g of the PVA film with 10 % CNF and 10 % TA was 87 °C, 12 °C higher than that of the neat PVA film. For three-component PVA biocomposites with 4 % and 6 % CNF and with all weight percentages of TA, the T onset shifted to a higher temperature range by about 30 °C compared to the neat PVA film. The PVA film with 2 % CNF and 10 % TA exhibited about a 20° higher contact angle than the neat PVA film. Moreover, the addition of both fillers to the PVA matrix resulted in PVA biocomposites with lower water absorption. PVA film with 10 % TA absorbed about 90 % less water and PVA film with 10 % CNF and 10 % TA absorbed about 80 % less water than the neat PVA film after the films were soaked in water for one hour. The better properties of the composite films produced are due to hydrogen and ester bonds between the components of the composite, which was confirmed by FT-IR spectroscopy. Antioxidant effective films were also obtained due to the biologically active TA to the PVA and PVA/CNF systems. [Display omitted] [ABSTRACT FROM AUTHOR]

Poly(vinyl alcohol) (PVA) biocomposite films reinforced with cellulose nanofibrils (CNF) and biologically active tannic acid (TA) were prepared. The influence of different concentrations of CNF and TA in the PVA polymer matrix was investigated in terms of mechanical properties, thermal properties and hydrophobicity improvement of the prepared films. The results showed that in all cases the addition of CNF and TA improved the values of tensile strength and elastic modulus. The PVA film with 10 % CNF exhibited a 30 % higher tensile strength, and the three-component PVA film with 2 % CNF and 10 % TA (P2C10T) exhibited a 40 % higher tensile strength compared to the neat PVA film. The thermal properties (T g , T onset) of the PVA biocomposite films were greatly improved, with a significant effect observed for the three-component PVA films. The T g of the PVA film with 10 % CNF and 10 % TA was 87 °C, 12 °C higher than that of the neat PVA film. For three-component PVA biocomposites with 4 % and 6 % CNF and with all weight percentages of TA, the T onset shifted to a higher temperature range by about 30 °C compared to the neat PVA film. The PVA film with 2 % CNF and 10 % TA exhibited about a 20° higher contact angle than the neat PVA film. Moreover, the addition of both fillers to the PVA matrix resulted in PVA biocomposites with lower water absorption. PVA film with 10 % TA absorbed about 90 % less water and PVA film with 10 % CNF and 10 % TA absorbed about 80 % less water than the neat PVA film after the films were soaked in water for one hour. The better properties of the composite films produced are due to hydrogen and ester bonds between the components of the composite, which was confirmed by FT-IR spectroscopy. Antioxidant effective films were also obtained due to the biologically active TA to the PVA and PVA/CNF systems. [Display omitted] [ABSTRACT FROM AUTHOR]

The interest in nanocellulose made from woody biomass has been growing rapidly; however, detailed studies on the environmental performance of nanocellulose have only been reported on a few occasions. To fulfill this gap, the environmental performance of nanofibrillated cellulose fabricated from thermo-groundwood (removal of extractives, lignin and hemicelluloses, TEMPO oxidation and homogenization processes were included) was evaluated by means of a Life Cycle Assessment. The results show that the purification process contributes more than 95% of the impact. It is associated with a relatively high consumption of electrical energy and ancillary chemicals, i.e., cyclohexane and acetone. The global warming potential of 1 kg of nanofibrillated cellulose is as high as 800 kg CO 2 equivalents. Even in the case that in addition to the extractives and the hemicelluloses also lignin is considered as a potentially valuable co-product, and the latter takes over some of the burden, the impact of nanofibrillated cellulose remains relatively high, at around 400 kg CO 2 equiv. per kg of nanocellulose. While the primary energy consumption is around 19.000 MJ per kg of nanofibrillated cellulose, or 10.100 MJ in the case that the lignin is considered as a potentially valuable co-product. The study also had a methodological goal, i.e., the impact indicators were calculated using the three most relevant evaluation methods: ILCD/PEF, CML 2001 and ReCiPe 2016. These three methods show similar results for the impact on global warming and acidification. However, in the case of impacts on some other indicators, significant deviations in the obtained impact scores were observed with respect to the results for the three methods. Taking into account the background data of the methods, ReCiPe 2016 was found to be the most up-to-date method and can currently be considered as the preferable Life Cycle Impact Assessment method. Image 1 • Environmental footprint of the nanocellulose is considerable (e.g. 800 kg CO 2 eq.). • The purification contributes 95% to the environmental footprint of the nanocellulose. • Three the most relevant LCIA methods results were compared. • Current LCIA methods could be improved with regard to AP and ODP models. [ABSTRACT FROM AUTHOR]

Relevant properties of stone pine ( Pinus pinea ) wood have been only fragmentarily addressed in the past, which has been recognized as a limiting factor for its potential applications. The sorption properties, permeability to water, extractives content and durability against fungi of Pinus pinea sapwood and heartwood were therefore determined in the present research. A SEM analysis was also performed. The Meyer-Veltrup model for material resistance was used to test relevant data. The results showed that sapwood of P. pinea fits into durability class 5 (very susceptible wood), while heartwood meets the requirements of durability class 2 (durable wood), if the mass loss after fungal exposure is considered as the sole criteria for classification. Heartwood contains up to 15% of lipophilic compounds, contributing to its hydrophobicity and influencing its sorption properties. In contrast, sapwood is very permeable and hence takes up a lot of water, while heartwood, with a higher resin content, exhibits better water performance. The higher durability of stone pine heartwood against wood decaying fungi can be linked to the presence of phenolic extractives and hydrophobic properties. [ABSTRACT FROM AUTHOR]

The effects of various drying techniques, such as air, oven, freeze, and spray drying, on the morphological, thermal, and structural behaviors of two different nanofibrillated cellulose (NFC) materials were investigated. Field emission scanning electron microscopy (FE-SEM) observations indicated an interlaced network formation of predominantly in-plane fibrillar orientation for air- and oven-dried samples, while freeze and spray drying resulted in the formation of coarse and fine powder fractions. Comparison of redispersed powders obtained by freeze and spray drying indicated that aggregation phenomena are significantly reduced in freeze-dried specimens. Rheological and sedimentation analysis revealed that the freeze-dried NFC powders are more stable than spray-dried NFC powders when redispersed in water. Aggressive dehydration processes, such as freezing or heating, significantly influence the thermal stability of the dried cellulose samples. On the contrary, the crystallinity properties of dried NFC materials are very similar regardless of the drying treatment. [ABSTRACT FROM AUTHOR]

Various types of wound-associated wood, such as discoloured wood including knots of living and dead branches, were sampled from common beech trees ( Fagus sylvatica L.), extracted, and the extracts have been analysed by GC and colourimetry assay. Sequential pressurised solvent extraction was applied with cyclohexane and aqueous methanol. The yield of hydrophilic compounds was three to five times higher than that of lipophilic extractives. The fractions differed mainly in their hydrophilic moieties. The lipophilic extractives consisted mainly of free fatty acids, fatty alcohols and free sterols. The yield of fatty acids was slightly higher in reaction zones and knots. The content of free sterols was highest in the reaction zones and in the discoloured wood. The hydrophilic extractives consisted of soluble sugars, various acids and phenolic compounds with catechin as the dominant one. Expectedly, the yield of phenolic extractives and catechin (proanthocyanidins) was highest in knots and wound-wood. Discoloured wood gave rise to lower amounts of catechin. [ABSTRACT FROM AUTHOR]

The extraction conditions have been evaluated concerning the recovery of specific polyphenols from Scots pine (Pinus sylvestris) knots by means of an accelerated solvent extractor. The composition of the extracts was determined by gas chromatography, gas chromatographymass spectrometry, and high-performance size-exclusion chromatography. The main phenolic compounds are the stilbenes pinosylvin and its monomethyl ether and the lignan nortrachelogenin (NTG), and their amounts vary a lot from sample to sample. The sequential extraction with a nonpolar solvent as a first step for removing the lipophilic compounds was the most efficient approach for the recovery of both pinosylvins and NTG. For food applications, hot water and 85% aqueous ethanol were good solvents for the production of the substances in focus. An industrial knotwood sample from a pulp mill was sequentially extracted with cyclohexane and ethanol/water (95:5) in a large-scale Soxhlet equipment. The results show that the industrial production of pinosylvins and NTG from knots is feasible. [ABSTRACT FROM AUTHOR]

Abstract: Different types of southern European hardwoods and softwoods were subjected to a liquefaction process with glycerol/diethylene glycol. The liquefied spruce wood was reacted in a condensation reaction in the hot press with different melamine–formaldehyde and melamine–urea–formaldehyde resin precursors and used as adhesives for wood particle boards. The mechanical properties of these particle boards and the determination of formaldehyde release, proved that addition of 50% of the liquefied wood to such resin precursors caused the product to meet the European standard quality demands for particle boards. Up to 40% reduction of the formaldehyde emission was achieved. The temperature of the press unit was lowered from 180°C to 160°C with no significant influence on the mechanical properties. On the basis of the presented results it was possible to conclude that liquefied wood can be used as substitute for synthetic resin precursors in adhesives that are used for the particle board production. [Copyright &y& Elsevier]

[Display omitted] • New multifunctional antibacterial and ultraviolet protective cotton cellulose was developed. • Sumac leaf extract is a novel green reducing and stabilising agent for the biosynthesis of Ag NPs. • Ag NPs and sumac leaf extract additively contribute to the antimicrobial and UV protection of cotton. • Reactive polysilixane matrix enhances cotton's ability to embed and physically trap Ag NPs. • Chemically modified cotton fabric shows high wash resistant multifunctionality. A novel facile and eco-friendly procedure for fabrication of multifunctional antibacterial and ultraviolet (UV) protective cotton surface was presented, including premodification of cellulose fibres with a polysiloxane matrix, followed by green in situ biosynthesis of silver nanoparticles (Ag NPs) in the presence of sumac leaf extract as a reducing and stabilising agent. During the biosynthesis, face-centred cubic Ag NPs with an average size of 52–105 nm were generated on the cotton fibres. Increasing the concentration of the AgNO 3 precursor resulted in increased concentration of Ag NPs of 50–11,000 mg/kg. The chemically modified cotton surface exhibited excellent antimicrobial and UV protection properties. The additive antibacterial activity of Ag NPs and sumac leaf extract showed biocidal activity against S. aureus even at the lowest Ag NP concentration of 50 mg/kg, and in the case of E. coli , biocidal activity was achieved at a concentration of 340 mg/kg. The presence of both Ag NPs and sumac leaf extract provided UV protection factor greater than 40, irrespective of Ag NP concentration. The increase in Ag NP concentration significantly improved the durability of the coating. [ABSTRACT FROM AUTHOR]