Developments in research on the beating process since the Cambridge symposium are reviewed with respect to changes in the individual fibres and the manner in which these primary effects influence pulp and paper properties . The following are regarded as primary effects breaking of intrafibre bonds, external fibrillation and foliation, formation of fines and fibre shortening .
The breaking of intrafibre bonds can take place at various dimensional levels, but can be referred to changes in the hydrogen bond structure. Properties discussed include specific volume, specific surface, flexibility, flow resistance, drainage resistance, wet web strength, drying tensions, bonded area, density, tenacity, extensibility, Young’s modulus, rupture energy, creep, tear ,factor and folding endurance.
Experiments on the influence of beating on the flow resistance and drainage resistance are described in some detail .