Water has a major influence on wood properties, especially dynamic moisture cycles, which affect the wood in outdoor applications. It is thus important to understand the penetration and distribution of water in wood. In this study, rainfall events were simulated to correspond to water immersion periods of 1 h. Specimens were imaged by magnetic resonance imaging (MRI) after 1 h of immersion. These measurements were used to determine the water distribution in the wood and to elucidate changes during the drying of specimens of five wood species: sweet chestnut heartwood (Castanea sativa), European larch heartwood (Larix decidua), Scots pine heartwood and sapwood (Pinus sylvestris) and Norway spruce (Picea abies). Both gravimetric and MRI analysis showed that after 1 h of immersion, pine sapwood took up the highest amount of water, followed by spruce wood. Considerably lower moisture contents were determined in pine heartwood, chestnut and larch, which correlated with a lower signal intensity. The outer parts of the specimens exhibited similar patterns with all of the specimens. The most variable results were the moisture content time profiles in the middle part of the specimens. Comparison of the MRI measurements and gravimetrically determined moisture contents during drying validated the MRI measurements and confirmed the method to be suitable for giving comprehensive information about the water drying kinetic. Journal Cellulose is the highly ranked journal within the field Material Science, paper and wood. Besides respective article, there were the following similar articles published: KRŽIŠNIK, Davor, BRISCHKE, Christian, LESAR, Boštjan, THALER, Nejc, HUMAR, Miha. Performance of wood in the Franja partisan hospital : Elektronski vir. Wood material science & engineering, ISSN 1748-0280, 2019, vol. 14, no. 1, str. 24-32, ilustr. http://www.tandfonline.com/doi/full/10.1080/17480272.2018.1438512, doi: 10.1080/17480272.2018.1438512. [COBISS.SI-ID 2878601]
COBISS.SI-ID: 2966665
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 chromatographyflame ionization detector (GC-FID), gas chromatographymass spectrometry (GC-MS), high-performance liquid chromatography (HPLC) and proton nuclear magnetic resonance (1H-NMR) spectroscopy.
COBISS.SI-ID: 2989449
A novel low temperature approach was developed for the deposition of rutile TiO2 particles on a wood surface. The establishment of TiO2-wood coordinative bonds of titanium ions with hemicellulose and lignin were proven. TiO2 deposited on wood treated with SDS became highly hydrophobic. Our investigations proved that a low temperature hydrothermal process is a suitable way to deposit rutile nanoparticles also on surfaces of wood and not only on surfaces of other substrates, what has been shown in scientific literature so far. Some other publications with regards to this topics are: - PORI, Pavel, PETRIČ, Marko. Enhancement possibilities for surface finished wood properties with hydrothermal deposition of titania particles. Pro Ligno, ISSN 1841-4737, 2017, vol. 13, nu. 4, str. 316-322. http://www.proligno.ro/ro/articles/2017/4/PORI.pdf. [COBISS.SI-ID 2836617] PORI, Pavel, OREL, Boris, VILČNIK, Aljaž, SEVER ŠKAPIN, Andrijana, PETRIČ, Marko. Influence of reaction conditions of the crystalline form of hydrothermally deposited TiO2 on surfaces of spruce wood. V: HORACEK, P. (ur.). InWood 2015 : Innovations in wood materials and process : Brno, Czech republic, May 19-22, 2015. Brno: Mendel University in Brno. 2015, str. 105-106. [COBISS.SI-ID 2388617]
COBISS.SI-ID: 2518153
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. Besides respective article, there were the following similar articles published: KRŽIŠNIK, Davor, LESAR, Boštjan, THALER, Nejc, HUMAR, Miha. Performance of bark beetle damaged Norway spruce wood against water and fungal decay. Bioresources, ISSN 1930-2126, 2018, vol. 13, iss. 2, str. 3473-3486. BRISCHKE, Christian, HESSE, Carola, MEYER-VELTRUP, Linda, HUMAR, Miha. Studies on the material resistance and moisture dynamics of Common juniper, English yew, Black cherry, and Rowan. Wood Material Science & Engineering, ISSN 1748-0272, 2018, vol. 13, iss. 4, str. 222-230. MEYER, Linda, BRISCHKE, Christian, ALFREDSEN, Gry, HUMAR, Miha, FLATE, Per Otto, ISAKSSON, Tord, LARSSON, Pia Brelid-, WESTIN, Mats, JERMER, Jöran. The combined effect of wetting ability and durability on outdoor performance of wood : development and verification of a new prediction approach. Wood Science and Technology, ISSN 0043-7719, 2017, vol. 51, no. 3, str. 615-637.
COBISS.SI-ID: 2890633
Tannin-based foams were successfully prepared, using Norway spruce and maritime pine tannins. Various parameters, including the amount of procyanidins, were varied in order to observe the effect of changes in the density of the foam, on the structure its pores, and on the homogeneity, compressive strength, and compressive modulus of the foams. It was found that an optimum amount of spruce tannin exists, which results in a foam with the lowest density whereas the amount of cross-linker affects homogeneity, and the foam morphology is defined by the surfactant. A partial replacement of pine tannin with spruce tannin decreased the foaming temperature and led to decreased compressive strength and a decreased compressive modulus of the foams. The main attribute affecting the reaction was the amount of polyphenols, or the amount of impurities (cellulosic sugars) present in the tannin extract.
COBISS.SI-ID: 1132970
Thermal modification (TM) is the most important commercial modification procedure. TM wood has improved durability, but its performance does not meet expectations predominately under moist conditions. To reduce water uptake of TM wood, Norway spruce specimens were treated with suspensions of a natural wax by dipping or by vacuum-pressure impregnation. Wax treated specimens were subsequently thermally modified at 185, 200, 215, and 230°C. Control specimens were heated up to 100°C only. Contact angle (CA), short-term and long-term water uptake, bending strength and performance against wood decay fungi of the resulting material were determined. The results show that a combination of wax treatment and TM have a synergistic effect that considerably improves hydrophobicity, reduces liquid water uptake, slows down water vapour uptake, and improves the resistance against fungal decay of the treated material. Besides respective article, there were the following similar articles published: LESAR, Boštjan, HUMAR, Miha. Use of wax emulsions for improvement of wood durability and sorption properties. European journal of wood and wood products, ISSN 0018-3768. [Print ed.], 2011, vol. 69, no.2, str. 231-238. LESAR, Boštjan, STRAŽE, Aleš, HUMAR, Miha. Sorption properties of wood impregnated with aqueous solution of boric acid and montan wax emulsion. Journal of applied polymer science, ISSN 0021-8995, 2011, vol. 120, no. 3, str. 1337-1345. LESAR, Boštjan, PAVLIČ, Matjaž, PETRIČ, Marko, SEVER ŠKAPIN, Andrijana, HUMAR, Miha. Wax treatment of wood slows photodegradation. Polymer degradation and stability, ISSN 0141-3910, 2011, vol. 96, no. 7, str. 1271-1278. LESAR, Boštjan, KRALJ, Polonca, HUMAR, Miha. Montan wax improves performance of boron-based wood preservatives. International biodeterioration & biodegradation, ISSN 0964-8305. [Print ed.], 2009, vol. 63, no. 3, str. 306-310.
COBISS.SI-ID: 2601097
New environmentally friendly concepts of protection of wood to fungal decay are not based on application of biocides, but on increased water repellence of wood. In the paper it is reported on hydrophobisation and decrease of equilibrium moisture content in Norway spruce wood with polymerisation of hydrophobic monomers in wood cell walls. It was found that Norway spruce wood after treatment with octadecyltrichlorosilane exhibited reduced water uptake by the wood cell walls, lowered water vapour sorption, and signi?cantly increased dimensional stability of wood in terms of anti-swelling ef?ciency. Hydrophobicity and lower equilibrium moisture content were shown to cause increased resistance of the treated samples against brown-rot decay and molds. Besides respective article, there were the following similar articles published: WEIGENAND, Oliver, HUMAR, Miha, GEOFFREY, Daniel, HOLGER, Militz, CARSTEN, Mai. Decay resistance of wood treated with amino-silicone compounds. Holzforschung : International Journal of the Biology, Chemistry, Physics and Technology of Wood, ISSN 0018-3830. Tiskana izdaja, 2008, vol. 62, no. 1, str. 112-118. KUMAR, Anuj, RICHTER, Jan, TYWONIAK, Jan, HAJEK, Petr, ADAMOPOULOS, Stergios, PETRIČ, Marko, ŠEGEDIN, Urban. Surface modification of Norway spruce wood by octadecyltrichlorosilane (OTS) nanosol by dipping and water vapour diffusion properties of the OTS-modified wood. Holzforschung : International Journal of the Biology, Chemistry, Physics and Technology of Wood, ISSN 0018-3830. Tiskana izdaja, 2018, vol. 72, iss. 1, str. 45-56. https://www.degruyter.com/view/j/hfsg.2018.72.issue-1/hf-2017-0087/hf-2017-0087.xml, doi: 10.1515/hf-2017-0087. [COBISS.SI-ID 2801545] KUMAR, Anuj, RYPAROVÁ, Pavla, PETRIČ, Marko, TYWONIAK, Jan, HAJEK, Petr. Coating of wood by means of electrospun nanofibers based on PVA/SiO2 and its hydrophobization with octadecyltrichlorosilane (OTS). Holzforschung : International Journal of the Biology, Chemistry, Physics and Technology of Wood, ISSN 0018-3830. Tiskana izdaja, 2017, vol. 71, iss. 3, str. 225-231. https://www.degruyter.com/view/j/hfsg.ahead-of-print/hf-2016-0108/hf-2016-0108.xml?format=INT, doi: 10.1515/hf-2016-0108. [COBISS.SI-ID 2697097] PORI, Pavel, VILČNIK, Aljaž, PETRIČ, Marko, SEVER ŠKAPIN, Andrijana, MIHELČIČ, Mohor, SURCA, Angelja Kjara, NOVAK, Urban, OREL, Boris. Structural studies of TiO[sub]2/wood coatings prepared by hydrothermal deposition of rutile particles from TiCl[sub]4 aqueous solutions on spruce (Picea Abies) wood. Applied Surface Science, ISSN 0169-4332. [Print ed.], 2016, vol. 372, str. 125-138, ilustr. http://www.sciencedirect.com/science/article/pii/S0169433216305104, doi: 10.1016/j.apsusc.2016.03.065. [COBISS.SI-ID 2518153]
COBISS.SI-ID: 2593417
Different kinds of tannin-based foams were developed in the recent past with fisetinidin/robetinidin-typetannins extracted from mimosa (Acacia mearnsii) or quebracho (Schinopsis lorentzi) bark; or procyanidin-type tannins from pine (Pinus pinaster and Pinus radiata). These biobased porous products revealedexcellent properties similar to their synthetic counterparts in many applications. Norway spruce (Piceaabies) bark is another large potential source of procyanidin-type tannins. In this study rigid and homo-geneous foams were produced from purified tannins containing at least 80% of polyflavonoid condensedtannins. This paper deals with the study of spruce tannins reactivity for rigid foam formulations. Charac-terization results have point out their very good mechanical resistance (% ) 0.08 MPa), and low thermalconductivities (% ( 0.045 W/m/K) at low densities (d ( 50kg/m3).
COBISS.SI-ID: 2380425
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 CNF Other articels from the field of nanocellulose research: ŽEPIČ, Vesna, POLJANŠEK, Ida, OVEN, Primož, SEVER ŠKAPIN, Andrijana, HANČIČ, Aleš. Effect of drying pretreatment on the acetylation of nanofibrillated cellulose. Bioresources, ISSN 1930- 2126, 2015, vol. 10, 4, str. 8148-8167. http://www.ncsu.edu/bioresources/BioRes_10/BioRes_10_4_8148_Zepic_POSH_Props_Dried_Acetylated_Nanofibrill_Cellulose_7849.pdf. [COBISS.SI-ID 2454921] TSALAGKAS, Dimitrios, LAGAŇA, Rastislav, POLJANŠEK, Ida, OVEN, Primož, CSOKA, Levente. Fabrication of bacterial cellulose thin films self-assembled from sonochemically prepared nanofibrils and its characterization. Ultrasonics Sonochemistry, ISSN 1350-4177, 2016, no. 1, vol. 28), str. 136-143, ilustr., doi: 0.1016/j.ultsonch.2015.07.010. [COBISS.SI-ID 2418569] ŽEPIČ, Vesna, ŠVARA FABJAN, Erika, KASUNIČ, Marta, CERC KOROŠEC, Romana, HANČIČ, Aleš, OVEN, Primož, SLEMENIK PERŠE, Lidija, POLJANŠEK, Ida. Morphological, thermal, and structural aspects of dried and redispersed nanofibrillated cellulose (NFC). Holzforschung, ISSN 0018-3830. Tiskana izdaja, 2014, vol. 68, no. 6, str. 657-667. http://www.degruyter.com/view/j/hfsg-ahead-of-print/hf-2013-0132/hf-2013-0132.xml?format=INT, doi: 10.1515/hf-2013-0132. [COBISS.SI-ID 2176905]
COBISS.SI-ID: 2670985
The interaction between xylem phenology and climate assesses forest growth and productivity and carbon storage across biomes under changing environmental conditions. We tested the hypothesis that patterns of wood formation are maintained unaltered despite the temperature changes across cold ecosystems. Wood microcores were collected weekly or biweekly throughout the growing season for periods varying between 1 and 13 years during 1998-2014 and cut in transverse sections for assessing the onset and ending of the phases of xylem differentiation. The data set represented 1321 trees belonging to 10 conifer species from 39 sites in the Northern Hemisphere and covering an interval of mean annual temperature exceeding 14 K. The phenological events and mean annual temperature of the sites were related linearly, with spring and autumnal events being separated by constant intervals across the range of temperature analysed. At increasing temperature, first enlarging, wall-thickening and mature tracheids appeared earlier, and last enlarging and wall-thickening tracheids occurred later. Overall, the period of wood formation lengthened linearly with the mean annual temperature, from 83.7 days at -2 °C to 178.1 days at 12 °C, at a rate of 6.5 days °C-1. April-May temperatures produced the best models predicting the dates of wood formation. Our findings demonstrated the uniformity of the process of wood formation and the importance of the environmental conditions occurring at the time of growth resumption. Under warming scenarios, the period of wood formation might lengthen synchronously in the cold biomes of the Northern Hemisphere.
COBISS.SI-ID: 2558089