European Journal of Wood and Wood Products
Springer Science+Business Media
About: European Journal of Wood and Wood Products is an academic journal published by Springer Science+Business Media. The journal publishes majorly in the area(s): Materials science & Composite material. It has an ISSN identifier of 0018-3768. Over the lifetime, 5907 publications have been published receiving 70563 citations. The journal is also known as: Holz (Berlin. Print) & Holz (Berlin. Internet).
Papers published on a yearly basis
TL;DR: In this paper, the chemical composition of raw materials potentially useful for hydrothermal processing as well as the results reported on the kinetics of hemicellulose hydrolysis by water treatments are reviewed.
Abstract: Hydrothermal processing of lignocellulosic materials (wood or agricultural residues) causes a variety of effects including extractive removal, hemicellulose hydrolysis and alteration of the properties of both cellulose and lignin. This article reviews the chemical composition of raw materials potentially useful for hydrothermal processing as well as the results reported on the kinetics of hemicellulose hydrolysis by water treatments. The fundamentals of the mathematical modelling of hemicellulose degradation reactions by pseudohomogeneous kinetics and by severity factors are reviewed. Additional information on the effects caused by hydrothermal treatments on lignin and cellulose is also provided.
TL;DR: In this article, mild thermal treatments of wood according to a two-step process which leads to improved dimensional stability and improved timber performance were investigated by solid phase CP-MAS 13C-NMR to understand at molecular level the reasons for the improvements reported.
Abstract: Relatively mild thermal treatments of wood according to a two step process which leads to improved dimensional stability and improved timber performance were investigated by solid phase CP-MAS 13C-NMR to understand at molecular level the reasons for the improvements reported. All the occurrences described appear to be the consequence of reactions which are known in wood chemistry. These are the formation of acetic acid liberated from the hemicelluloses, which further catalyses carbohydrates cleavage, causing a reduction of degree of polymerisation of the carbohydrates. Acid catalysed degradation results in the formation of formaldehyde, furfural and other aldehydes as well as some lignin cleavage at Cα and O4 and believed to cause some aldehyde production from lignin units Cγ, all occurring in the first reaction step. Lignin autocondensation through the cleaved, positively charged benzylic Cα to form some methylene bridges presumably starts already to occur in this first phase. The increase in the number of free reactive sites on the aromatic ring of some lignin units already occurs in this phase but continues into the next. In the second treatment step completion of the autocondensation of lignin is believed to occur through the formation of methylene bridges connecting aromatic rings. The aromatic nuclei sites are released by demethoxylation and through the cleaved, positively charged benzylic Cα. Reactions of some of the aldehyde groups formed in the first step phase occur with lignin aromatic nuclei sites to connect aromatic rings through methylene bridges. The extent of these reactions is mild, but nonetheless they lead to an increase in cross-linking with consequent improvement in dimensional stability and decreased hygroscopicity of wood.
TL;DR: In this paper, Fourier transform infra red spectroscopy (FTIR) was used to study the chemical transformation of the cell-wall material and associated with improved wood qualities.
Abstract: Wood specimens of Beech (Fagus silvatica L.) and Scots pine (Pinus sylvestris L.) modified by a hydrothermal treatment process were analysed by means of Fourier transform infra red spectroscopy (FTIR). The chemical transformation of the cell-wall material was studied and associated with improved wood qualities. For this purpose, FTIR spectroscopy was used as since this technique has been found appropriate to determine the intensity of specific bonds and functional groups within the polymeric structure. Cleavage of acetyl groups of the hemicellulose has been found to occur in the first treatment step under moist conditions and elevated temperature. This results in the formation of carbonic acids, mainly acetic acid. Most of the acetyl groups were found to be cleaved during the treatment of wood at high temperature, whereas only partial deacetylation was found to occur at moderate treatment temperature. The concentration of accessible hydroxyl groups was measured by acetylation and found reduced after treating at high temperature. Esterification reactions were found to occur under dry conditions at elevated temperature in the curing step, indicated by the increase of the specific ester carbonyl peak at 1740 cm−1 in the FTIR spectrum. The esters that were formed turned out to be mainly linked to the lignin complex, considering that the newly formed carbonyl groups were found present in heat-treated wood, yet were found to be absent in the isolated holocellulose. Esterification contributes to a decrease of hygroscopicity of wood and consequently improvements of its dimensional stability and durability. However, the role of esterification in the decrease of hygroscopicity in the hydrothermal treatment process examined is believed to be minor compared to the influence of cross-linking reactions known to occur during thermal treatment of wood.
TL;DR: In this paper, the authors used bending test data from the ASTM 2017 standard to show that such treatment may create a 10 to 50% reduction in MOR and deflection, which will limit the use of such wood for structural purposes.
Abstract: and 46% for P. placenta. About 56% and 54% weight loss were obtained for southern pine control exposed to G. trabeum and P. placenta, respectively. The weight loss of the water and acetone extracted heat-treated sample exposed to P. placenta was 49.7% and 53.9%, respectively. Only about 11% and 14.8% weight loss was obtained for water and acetone extracted samples exposed to G. trabeum. The moisture content of the tested samples was about 70 ± 10% for the un-heated controls and 50 ± 10% for heat-treated samples. This treatment may modify the durability from non-resistant to moderate/resistant species depending on the fungus species as defined in the ASTM 2017 standard. The data from the bending test indicate that such treatment may create a 10 to 50% reduction in MOR and deflection, which will limit the use of such wood for structural purposes.