A new method for measuring RBA applied to the Page equation for the tensile strength of paper

The Page equation is the most widely used equation to predict the tensile strength of paper. In this paper, the derivation of the Page equation is examined critically and a modified Page equation is proposed based on a newly developed method to calculate the relative bonded area from sheet density and fibre shape. The predictions of the original and modified Page equations were then tested against twelve sets of sheets made from different unbleached, never dried radiata pine kraft pulps. The bond strength was used as a fitting parameter. The best fit bond strengths varied so widely as to make it impossible to use either the original or modified Page equation to predict tensile strength, without prior knowledge of the bond strength applicable to that data set.