The Dispersion Science of Papermaking

Abstract

Paper is one of the most important inventions in the history of civilization, and it is an essential commodity to all people in the world. The fact that we make ubiquitous use of a score of paper products makes it easy to underestimate its value and significance. This review is intended to put into perspective the dispersion science involved in papermaking and to describe how our understanding of key processes has evolve since its conception, approximately 2000 years ago, from art to science. Paper is formed from a slurry of fibers and much smaller particles that are often called "fines" and other chemical additives. Ahead of the paper forming process the slurry is subjected to a series of steps, including treatment with polyionic species and passage through unit operations that impose shear forces on the papermaking suspension. These steps alternately disperse the solids apart or re-gather them back together. The overall process is optimized to achieve a highly uniform product, while at the same time achieving high efficiency in retaining fines in the sheet and allowing water to drain relatively quickly from the wet paper as it is being formed. As we approach the 1900-year anniversary of the first detailed account of the papermaking process, it is the goal of this review to explore the scientific principles that underlie the art of papermaking, emphasizing the state of dispersion of the fibrous slurries during various stages of the manufacturing process. Some concepts that arise out of the experience of papermakers have potential applications in other fields.

Poly(ethylene oxide)‐block‐poly[2‐(dimethylamino)ethyl methacrylate] as Strengthening Agent in Paper: Dynamic Mechanical Characterization

“…Particle sizes of polymer in water solution are listed in Table 1. The values are close to the values reported in the literature, where PEO with a molecular weight more than a million has been reported to have an HS of 200 nm 7. HS of individual polymers must be smaller, and all of the polymers form some kind of clusters in water solution.…”

“…Poly(ethylene oxide) (PEO) is widely used in paper industry mainly to improve retention 7. It is common to use co‐factors to improve affinity of PEO into fibers in pulp and paper processes.…”

“…It is important to study polymer behavior in water solution in order to predict its behavior as an additive. Even though PEO visibly dissolves in water, it forms clusters, and the bigger the cluster the better the adsorption on fibers and fine particles 7. Therefore typical molecular weight of PEO used as paper additive is more than a million and the particle size is about 200 nm.…”

Comparison of alkaline pulping with steam explosion for glucose production from rice straw

“…Steam explosion is typically initiated at a temperature of 160-260 • C for several seconds to a few minutes before the material is exposed to atmospheric pressure (Kurabi et al, 2005;Sun & Cheng, 2002;Varga, Reczey, & Zacchi, 2004 On the other hand, chemical pulping methods attempt to dissolve the lignin with a minimum of dissolution or degradation of the cellulose and hemicellulose components of the fibers under high temperature and pressure. Historically, the most successful approaches to achieve these goals have employed NaOH (the soda process), SO 3 2− (the sulfite process), and alkaline S 2− (the kraft process) (Rojas & Hubbe, 2004).…”

Experimental investigation on momentum and drag reduction of Malaysian crop suspensions in closed conduit flow

“…Due to practical and economic reasons, papermaking technologists are interested in flocculation [16]. Flocculation effect paper strength, uniformity, appearance [17][18][19] and adversely affect subsequent operations, such as coating [20]. Flocculation and consequently the frictional pressured drop would be affect by any deviation in fiber properties particularly fiber length and flexibility.Also, many researchers [14,21] reported that fiber flexibility is dependent on cross-dimensional fiber properties and increases with the decrease of fiber cell wall thickness.…”