LIGHT-SCATTERING AND RELATIVE BONDED AREA - SIMULATION OF THE EFFECT OF FIBER COLLAPSE

The relative bonded area of paper sheets can be determined by measurin g their light scattering coefficient. The biggest difficulty with this technique is obtaining the value for the scattering coefficient of th e unbonded sheet. This value is determined by extrapolating a plot of the scattering coefficient against tensile strength for a series of sh eets with different degrees of either beating or wet pressing. However , it has been shown that the result of the extrapolation depends on wh ether beating or wet pressure is used for changing the sheet structure . In this paper we will show theoretically that the degree of fiber co llapse may be the main reason for the differences in the light scatter ing coefficient of the unbonded sheet.