Initial wet web strength of paper

Despite much research into and development within the complex area of the initial wet web strength of paper, no complete model has yet been developed to describe this property. This type of paper strength is the most important property to ensure an effective paper machine run. Furthermore, the process of strength development in the sheet forming and pressing portion of the process is the basis of the final paper strength. Recent investigations have focused on the surface interactions of fibers on the molecular level. There have also been several innovative findings about fiber swelling and the impact of swelling on the mechanical characteristics of fibers in wet conditions. Overall, progress obtained using new methodologies enables a deeper understanding of the mechanism of strength development. This review discusses these important areas by examining the literature and the authors’ own work to obtain a better understanding of the strength development in wet paper webs. This paper highlights that the fiber morphology and the dryness of the wet web have the greatest impact on the strength of the wet web. As fiber sources and machinery are fixed, the fiber water gel is one of the easiest factors to adjust via the process water quality and the use of chemical additives.