Inverkan av isostatisk komprimering på cellstrukturen

The influence of isostatic compression on the cell wall structure of wood By Dick Sandberg Abstract The aim of this study was to evaluate the response of the cellwall structure in Scots pine (Pinus sylvestris L.) samples to an isostatic compression. The annual ring orientation of the samples was either radial or tangential. The compression set of the each samples was determined during compression at a mean moisture content of 10 % and a temperature of 20°C. The structural changes were investigated in the Environmental Scanning Electron Microscope (ESEM). The samples were compressed between 50 to 70 % of their original thicknesses, which means the density of the samples was between 539 Kg/m3 to 1218 Kg/m3, according to composite mechanic, we can assume that the early and latewood are in parallel in the radial direction. This suggests that in the radial direction compared to the latewood the earlywood will be compressed significantly. The longitudinal compression was insignificant. The compressed wood retained up to 90 % of its original dimension when it was immersed in water. The swelling in the radial direction was four times greater than in the tangential direction. Cracks as a result of the compression deformation were observed both in the early-and late wood cellwalls.Upprättat; 1998; 20140904 (dicsan