Compression wood in knots and the effect on surface roughness.

• The microstructural and ultrastructural characteristics of knot wood were examined and related to paper properties. Norway spruce (Picea abies) chips were laboratory fractionated and sorted into a knot containing assortment and a non knot containing reference assortment. The proportions of compression wood in these two assortments were then assessed and the two chip assortments refined in pilot refiners. The knot containing portion was divided into wood from the upper branch, wood from the lower branch compression wood and wood surrounding the branch. Fibres from the three knotwood portions and the reference chips were extracted and measurements were made of fibre properties including fibre length, fibre width and cell wall thickness. The two chip assortments were refined in a pilot plant and the surface properties of laboratory sheets were measured. The knot containing chips had adverse effects on several paper properties. However, no clear relationship was established between surface roughness and the presence of compression wood fibres in knot wood. (6 fig, 12 ref)

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering (hsv//eng)

Nyckelord

Roughness

Compression wood

Knot

Chip

Chemical engineering

Kemiteknik

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