Microfibril angles of softwood and hardwood pulp fibres measured with white-light polarimetry

The objective of this study was to develop and apply a simple method for MFA measurement and use it for fibers with different morphology and some mechanical deformations.In this study, only fibers with significant sinusoidal light intensity curves were evaluated. The assessed MFA is an average value from all wall layers and structures in the polarised light beam. In thickwalled latewood fibers, the oriented S2-layer dominates, and low angles are measured with high light intensity differences between maximum and minimum intensity values within a 90°-range of polarisation filter position (for intensity difference see Figure 4). In thinwalled earlywood fibers, the S2-layer is much thinner, and the S1- and S3-layers affect the result much more than for latewood fibers. Subsequently, the resulting measured MFA shows higher values for this type of fibers. Due to the lower fiber wall mass, the intensity difference is also smaller