Surface analysis by ESCA of sulfite post‐treated CTMP

Abstract

SynopsisHandsheets of post-treated chemithermomechanical pulps (CTMP) and a sample of Whatman paper no. 1 were analyzed using an ESCA spectrometer. All of these samples revealed the presence of the C,, C,, and C, components in the carbon (1s) peak and the 0, component in the oxygen (1s) peak; the 0, peak component which was present in the other samples was missing from the Whatman paper. Pulp sulfonation produced a reduction in C, representing the group of carbon not bonded to oxygen, and an increase in C, with C, remaining relatively constant. These changes imply reductions in lignin and extractives and a corresponding increase in cellulose content on the fiber surface. Extrapolation of the C,, C,, C,/C,, and O/C curves of CTMP to zero percent sulfonation yielded the same values as those obtained for pure TMP. ESCA analysis allows us to monitor the increase of sulfur content as a function of sulfonation in accordance with results obtained from bulk pulp sulfonate content titration. INTRODUCTIONDespite the growth in the synthetic polymer industry, products made from wood fibers and cellulose still constitute the most important quantity of organic polymeric materials. Although the chemical composition of those materials are well characterized, much less is known about their surface chemistry, which in turn affects the properties of the final product. In the case of paper, for example, the quality of fiber-to-fiber bonding depends largely on the chemical nature of the fiber surface, which in turn determines the physical strength of paper and even its resistance to weathering and to photodegradation.Surface spectroscopic techniques, such as electron spectroscopy for chemical analysis (ESCA), reflectance (ATR) infrared spectroscopy, wettability measurements, and scanning electron microscopy (SEM) have potential of yielding chemical information for interfaces with a resolution of 10 A or better.','Since the ESCA technique is based on a direct analysis of the kinetic energy of electrons that have been excited by high energy x-rays and pulled away from their atomic environment, this technique is a powerful tool for the chemical analysis of surfaces of synthetic p~l y m e r s~-~ and natural or modified textiles fiber^.^^^ In fact, ESCA has already been employed in the characterization of the surface composition of wood fibers8*' and cotton fibers," and the results obtained seem very promising for the pulp and papers industries. The main objective of this study is to use the ESCA technique to characterize the changes in the surface chemistry of chemithermomechanical (CTMP) fibers when treated to various degrees of sulfonation. ESCA spectra of these fibers were also compared to the spectrum of Whatman paper no. 1, a material which was shown to have a surface composition rather close to that of cellulose. '-lo EXPERIMENTAL CTMP samples obtained from Kruger Inc. were cooked in a pressure bomb (1 L) for various periods of time ranging from 0 to 8.5 h in order to reach various degrees of sulfonation. The pulp sulfonation was d...

Surface analysis of explosion pulps by ESCA Part 1. Carbon (1s) spectra and oxygen-to-carbon ratios

“…C4 representing carbons linked to a carbonyl and a non-carbonyl -C~O is absent in our spectra due to the low concentration of carboxylic groups on the fiber surface which makes them undetectable when using the (Gelius et al 1970). As one can see in Table 2, data in this study are in good agreement with those reported in the literature (Dorris et al 1978(Dorris et al a, 1978Gray 1978;Hon 1984;Ahmed et al 1987aAhmed et al , 1987bAhmed et al , 1988Ahmed et al , 1989Grandmaison et al 1988;Barry et al 1990;Brinen et al 1989;Kamdem et al 1991;Young et al 1982). For example, the binding energy of C1, C2 and C3 on the cellulose surface in the report of lion (1984) were 285.0, 286.5 and 288.3 eV respectively, 284.9, 286.9 and 288.4 eV in the work of Young et al (1982), corresponding to our data, 284.8-285.0, 286.6-286.8 and 288.4-288.6 eV.…”

“…A tentative assignment for the component peaks of Ols peak was proposed. Barry et al (1990) studied the ESCA of sulfite post-treated CTMP. The ESCA technique was also used in alkaline sizes on paper surface and grafting of wood fibers (Brinen et al 1989;Kamdem et al 1991).…”

X-ray photoelectron spectroscopy study of red oak- (Quercus rubra), black cherry- (Prunus serotina) and red pine- (Pinus resinosa) extracted wood surfaces

“…7,17 The high carbon content in wood samples has been reported to be an indication of the presence of lignin and extractives on the wood surface. 7,17 The increase in O/C following extraction treatments is due to the partial removal of carbon-rich extractives such as fatty acids, terpenes, and phenolics.…”

Surface characterization of eucalyptus and ash wood veneers by XPS, TOF-SIMS, optic profilometry and contact angle measurements

“…The O/C ratio varied between 0.22 and 0.27 (Table 3). If experimental O/C ratio values are compared to those of pure compounds, 0.83 for cellulose, 0.33 for lignin and 0.1 for extractives [10] the preferential presence of lignin and extractives on the wood surface is demonstrated, mainly in the case of eucalyptus veneers. Moreover, the C1/C2 ratio provides an additional evidence to support the above interpretations.…”