Abstract
Pulps produced by mechanical defibration of sulphite treated black spruce wood chips contain large amounts of lignin. The degree of sulphonation of this lignin has a significant influence on the physical properties of handsheets made from the resulting pulps In earlier work we have described the factors affecting the sulphonation of black spruce.The aim of the present investigation was to determine the differences in reactivity of sulphite towards lignin in the middle lamella and cell wall of black spruce.Black spruce wood chips were well impregnated with sodium base sulphite solutions having pH 7, and then heated at 140° and 80°C for known times. The resulting sulphonated wood chips were cut into small sticks and embedded in Vestopal. Transverse sections, 150 nm thick, were placed on a carbon grid having a single 1 mm hole bearing a collodian film which had been carbon coated. Sulphur contents in the middle lamella and cell wall were determined with a Philips 400 TEM coupled with an EDAX 9100/60 analyser. The concentration of sulphur was taken to be proportional to the x-ray counts in the sulphur Kα window after background subtraction, as shown in Figure 1.
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Schedule a callMore From: Proceedings, annual meeting, Electron Microscopy Society of America
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