Fiber Bending Flexibility Evaluation by Worm-like Chain Model

A new method for characterizing fiber bending flexibility was developed by worm-like chain model proposed by Kratky-Porod, [1] which was first introduced to the pulp and paper field in this study. For the three types of pulps, the experimental results were compared with the KP chain model, and the resulting determination coefficients were all above 0.95, which proved that the model was feasible to be applied to these three fibers. The relation between fiber bending rigidity and that of cellulosic chains inside was discussed to deduce the fiber bending flexibility. The flexibility of an individual fiber can be approximated as the contribution of that of all the cellulose chains inside. By this method, the fiber flexibility values were determined to be in the range of 0.6×10 11 −3.5×10 11 N −1 ·m −2 , which was comparable to that of the conventional methods recorded in the literature.