Variability in the local structure and properties of paper

In this study, the variability in local bonded area has been computed by a novel method for both handsheets and machine-made papers. Microtensile specimens, with a stressed area of approximately 2 mm x 2mm, were cut from larger sheets and tested to failure, and their breaking length was plotted as a function of their local bonding index. It was found that for a sample of poorly formed kraft handsheets, there was no significant correlation between the local bonding index and tensile strength. However, a significant correlation was observed for machine made newsprint samples.