Surface analysis of press dried‐CTMP paper samples by electron spectroscopy for chemical analysis

Koubaa, Ahmed; Riedl, Bernard; Koran, Z.

doi:10.1002/(sici)1097-4628(19960718)61:3<545::aid-app18>3.0.co;2-#

Cited by 40 publications

(48 citation statements)

References 17 publications

(3 reference statements)

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“…This is in agreement with a previous study [127]. However, the weathering shows an opposite effect on the Ols spectra of heat-treated birch wood, decreasing fractional areas of the Oi and O3 components and increasing that of O2 (see Figure 4.25 (c)).…”

Section: Ols Peakssupporting

confidence: 93%

“…give Oi and O2 binding energies of 531.6 ± 0.4eV and 532.6 ± 0.1 eV, respectively (Table 4.10). The binding energies of Oi are in excellent agreement with those reported in the literature [127,140]. The binding energy of O2 component value is somewhat lower than that reported for birch and spruce chemicothermomechanical pulps [127].…”

Section: Chemical Changes Due To Irradiation Without Water Spray A) Fsupporting

confidence: 89%

“…The spectra fitting and component analysis were performed using the high-resolution spectra. The number of components and their binding-energy positions (shown in Table 3.3 below) were taken from Inari et al and Ahmed et al [127,140]. No specific chemical group is assigned to the O3 peak, since this peak is difficult to fit and unstable.…”

Section: Scanning Electron Microscopy (Sem)mentioning

confidence: 99%

“…In addition, the difficulty to distinguish between simple and double bonds between the oxygen and carbon atoms also leads to relatively sparse study on Ols peak of wood materials compared with the Cls peak reported in the literature [127]. It was suggested to compare the decomposition of this peak to known models [162].…”

Section: Ols Peaksmentioning

confidence: 99%

“…It was proposed that this component was associated to lignin and that increase in the Oi indicates a decrease in carbohydrates on the fiber surface and an increase in lignin and extractives [163]. It was also observed that eliminating lignin from the fiber surface by high temperature treatment decreased fractional area of Oi and increased that of O2 [127]. However, normally lignin relative content increases during heat treatment due to the degradation of hemicelluloses.…”

Section: Ols Peaksmentioning

confidence: 99%

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Study on the degradation mechanism of heat-treated wood by UV light /

Huang

2012

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Heat-treated wood is a wood product thermally treated at high temperatures in the range of 180°C and 240°C for its preservation without using any additional chemicals. Heat treatment modifies wood both chemically and physically. Amorphous polysaccharide content (hemicelluloses) decreases, condensation and demethoxylation of lignin take place, and certain extractives are removed. Consequently, heat-treated wood possesses new physical properties such as reduced hygroscopy, improved dimensional stability, better resistance to degradation by insects and micro-organisms, and attractive darker color. These new beneficial and attractive properties make heat-treated wood popular for indoor as well as outdoor applications.However, similar to untreated wood, heat-treated wood is also susceptible to degradation due to environmental conditions. Weathering results in poor aesthetics for heat-treated wood because of the discoloration and surface checking when exposed to UV radiation. However, investigations on the wettability changes, chemical changes, and microscopic changes of heat-treated wood after exposure to artificial weathering are very limited; and there is no publication available in the literature on the degradation taking place due to the weathering of heat-treated North American jack pine, aspen, and birch used in this study.This work was undertaken to study the weathering degradation mechanisms of the three North American regional species (jack pine (Pinus banksiana), aspen (Populus tremuloides\ and birch (Betula papyrifera)) heat-treated under different conditions to understand the chemical and physical changes taking place and to compare these changes with those of untreated controlled samples when they are exposed to artificial weathering with and without water spray for various periods. Several techniques and tools were used such as color measurement, contact angle test for wettability analysis, Fourier transforms infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) for chemical analysis, florescence microscopy (FM), and scanning electron spectroscopy (SEM) for microscopic structural analysis. These provide a great deal of insight into the degradation process.The results show that color changes occurring during weathering of heat-treated woods are due to the increasing lignin condensation and decreasing extractives content on wood surfaces caused by heat treatment. Changes in wettability during weathering of heattreated wood are induced by the combination of surface structural and chemical modifications. Lignin in heat-treated woods is more sensitive to weathering than other components. It is proposed that the weathering mechanism of heat-treated woods consists of the degradation of lignin matrix and extractives, which lightens the wood color. As a result, the color difference between the color of heat-treated wood before weathering and the color of the same wood during weathering increases with exposure time. Then, the leaching of other polymers present on wood surface takes place...

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Section: Ols Peakssupporting

confidence: 93%

Section: Chemical Changes Due To Irradiation Without Water Spray A) Fsupporting

confidence: 89%

Section: Scanning Electron Microscopy (Sem)mentioning

confidence: 99%

Section: Ols Peaksmentioning

confidence: 99%

Section: Ols Peaksmentioning

confidence: 99%

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Study on the degradation mechanism of heat-treated wood by UV light /

Huang

2012

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X‐ray Photoelectron Spectroscopy, Paper Surface Analysis By

Pamidimukkala¹

2000

Encyclopedia of Analytical Chemistry

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X‐ray photoelectron spectroscopy (XPS) also popularly known as electron spectroscopy for chemical analysis (ESCA) involves the irradiation of a solid surface in ultrahigh vacuum with monoenergetic soft X‐rays. The X‐rays cause electrons of an atom to be ejected and to be ionized as photoelectrons. The number of electrons and their kinetic energies are then measured. The energy of the emitted electron is very characteristic of the atom from which the electron originated and its environment. The XPS spectrum is a plot of the number of emitted electrons per energy interval versus their binding energies. Quantitation can be achieved either by fundamental parameter calculation or comparison with appropriate standards. In the pulp and paper industry, XPS has successfully been used to study migration of binder in coated paper, the surface chemistry of pulps and its effect on the properties of the final products; the adhesion between paper and polymer, toner or ink; and the chemical additives on the paper surface. As with most analytical instrumentation, XPS has its limitations and disadvantages and is often used in conjunction with other, complementary techniques such as SIMS (secondary ion mass spectrometry) and FTIR (Fourier transform infrared) spectroscopy for the identification of organic compounds on paper surfaces. XPS is surface sensitive which renders it useless if the underlying cause of the problem might be other than surface related. XPS provides only semiquantitative information. A more precise quantification of the elements is possible, but requires exhaustive calibration.

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