Faserflexibilität - Measuring the flexibility of pulp fibres

Fibre flexibility is a pulp property of considerable importance in the manufacture of paper. It influences the behaviour of the pulp suspension, the drainage characteristics of the sheet forming process and the strength and optical properties of the final paper. Despite the importance of this property there is no widely accepted method to measure fibre flexibility. The intention is to develop a method to measure fibre flexibility directly on single fibres. To get statistically significant results with reasonable effort the method has to be highly automatable. Fibres in highly diluted suspension in a well defined flow profile are loaded with defined hydrodynamic forces. Pictures are taken with a high-speed-camera and the fibres are captured by image analysis. The reaction of a fibre to the defined hydrodynamic load is used to calculate it´s flexibility. With this method influences on fibre flexibility by processes like cooking, bleaching, beating or drying can be investigated and systematically improved.