Influence of water on the elastic modulus of paper part 2:Verification of predictions of the H-bond theory
In Part I, an extension of the theory of hydrogen-bond-dominated solids was proposed. In Part 2, the predictions of the extended theory are tested statistically using recently reported measurements of elastic moduli for 24 papers over a wide range of moisture contents. Moduli were reported both quasi-statically and ultrasonically. Statistial analysis shows that the effect of moisture in lowering the elastic modulus of paper is greater when the modulus is measured quasi-statically. The rate of decrease in the logarithm of modulus with moisture content when measured sonically is about 75% of the rate of decrease measured quasi-statically. The ratio of the two measured moduli for an isotropically equivalent paper is statistically indistinguishable from a ratio obtained from measurements of the effectiveness of water in reducing these elastic modull.This supports one of the new predictions of the extended H-bond theory proposed in Part 1.