Thermal Modifications in Softwood Studied by FT‐IR and UV Resonance Raman Spectroscopies

Nuopponen, Markus; Vuorinen, Tapani; Jämsä, Saila; Viitaniemi, Pertti

doi:10.1081/wct-120035941

Cited by 237 publications

(155 citation statements)

References 24 publications

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“…But TH treatment also dissolves some extractives and their degradation products. Nuopponen et al (2004) observed migration of fats and waxes along axial parenchyma cells to the surface of steam heat-treated Scots pine wood at temperatures between 1008C and 1608C, whereas at temperatures above 1808C the fats and waxes disappeared from the surface. Mobilisation of extractives during THM-densification is responsible for darkening of the wood substrate; however, partial removal of extractives facilitates the access of water molecules to the cell wall.…”

Section: Chemical Alterationsmentioning

confidence: 95%

Resistance of thermo-hygro-mechanically (THM) densified wood to degradation by white rot fungi

Skyba¹,

Niemz

Schwarze

2009

HFSG

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Colonisation and degradation by the white rot fungi, Trametes versicolor and T. pubescens, were studied in wood of Norway spruce and beech subjected to three different treatments: (1) hygro-thermal treatment (1608C and 1808C), (2) mechanical densification, and (3) thermohygro-mechanical (THM) treatment including densification and post-treatment at different temperatures (1408C, 1608C and 1808C). The weight losses induced by the fungi were lowest in THM-densified woods. However, volume related numerical indicators for decay susceptibility did not show any significant improvements of THMdensified woods against both fungi. Analysis of the chemical composition of treated wood species revealed slight alterations in the content of polysaccharides and lignin. White rot fungi circumvented conditions restricting hyphal growth within the occluded tracheid lumina by hyphal tunnelling in the secondary walls of fibre tracheids in beech or by forming bore holes that transversally penetrated cell walls of earlywood tracheids in THM-densified spruce. The studies indicate that THM-densified beech and Norway spruce wood may have some potential in utility class 3 but are inappropriate for use in utility class 4.

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Section: Chemical Alterationsmentioning

confidence: 95%

Resistance of thermo-hygro-mechanically (THM) densified wood to degradation by white rot fungi

Skyba¹,

Niemz

Schwarze

2009

HFSG

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“…Thermal modification of woods was studied by examining chemical changes in wood struc ture by UVRR spectroscopy [70]. It was found that upon heat treatment at 180 • C or higher lignin became partly soluble in acetone.…”

Section: Heat Treatedmentioning

confidence: 99%

Raman Spectroscopic Characterization of Wood and Pulp Fibers

Agarwal

2008

Characterization of Lignocellulosic Materials

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This chapter reviews applications of Raman spectroscopy in the field of wood and pulp fibers. Most of the literature examined was published between 1998 and 2006. In addi tion to introduction, this chapter contains sections on wood and components, mechanical pulp, chemical pulp, modified/treated wood, cellulose I crystallinity of wood fibers, and the "self-absorption" phenomenon in near-infrared (IR) Fourier-transform (FT)-Raman spectroscopy. When needed, the sections are further categorized into various subsections. For example, the section on wood and components contains a variety of topics ranging from Raman band assignments to molecular changes during tensile deformation. From this review it will become clear that Raman spectroscopy has become an essential analytical technique in the field of wood and pulp fibers. IntroductionTechniques that can provide information on the chemical constitution of wood and pulp fibers and on processing-related changes of these materials are of great interest. Raman spectroscopy [1] is one such technique that provides fundamental knowledge on a molecu lar level and does not require chemical treatment of the sample (contrary to the case, for example, in fluorescence and electron microscopy). It has become an important analyt ical technique for nondestructive, qualitative, and quantitative analysis of materials. The technique is useful in a number of areas, including analytical measurements, mechan istic studies, and structural determinations. Studying a sample is very simple and usually involves sampling an area of interest by directing a laser excitation beam and analyzing the collected molecularly specific scattered light [2]. Although initially, obtaining good-quality Raman data required operator skill and training, this has started to change as a result of the commercial availability of compact, easy-to-use, integrated instruments at reasonable cost.Nevertheless, although the specificity of Raman spectroscopy is very high, its sensitivity is somewhat poor. Considering that only a small number of the incident laser photons are inelastically scattered, the detection of analytes present in very low concentrations is limited. To overcome this problem, special Raman signal-enhancing techniques can be applied. The two most prominent approaches are the resonance Raman effect [3] and the

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“…Regarding W TM , it is well known that, during thermal modification, AA liberated from hemicelluloses catalyses carbohydrate cleavage and leads to a reduction in the degree of polymerization of carbohydrates and formation of new ether linkages between lignin at high temperatures (Tjeerdsma et al 1998;Sivonen et al 2002;Nuopponen et al 2004;Tjeerdsma and Militz 2005;Windeisen et al 2009). Thus, the values of ASE′ for TM samples do not reflect the real reactions occurring in the cell wall during thermal modification.…”

Section: Asementioning

confidence: 99%

Novel hydrophobization of wood by epoxidized linseed oil. Part 1. Process description and anti-swelling efficiency of the treated wood

et al. 2014

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Abstract:The known method of wood modification by epoxidized linseed oil (ELO) has a limiting practical application due to the rapid polymerization of ELO in the presence of acetic acid (AA) needed as a catalyst. The present study was designed to develop an alternative method by means of a two-step process to avoid the rapid polymerization. The treatment options were tested on Scots pine sapwood, with the dimensional stability (DS) of the treated samples in focus. The new method provided an anti-swelling efficiency (ASE) in the range of 40-57%, which was even better than the thermally modified (TM) reference samples with 40% ASE. The developed two-step process is a feasible and practical approach for ELO treatment of wood.

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Thermal Modifications in Softwood Studied by FT‐IR and UV Resonance Raman Spectroscopies

Cited by 237 publications

References 24 publications

Resistance of thermo-hygro-mechanically (THM) densified wood to degradation by white rot fungi

Resistance of thermo-hygro-mechanically (THM) densified wood to degradation by white rot fungi

Raman Spectroscopic Characterization of Wood and Pulp Fibers

Novel hydrophobization of wood by epoxidized linseed oil. Part 1. Process description and anti-swelling efficiency of the treated wood

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