Mini-Encyclopedia of Papermaking Wet-End
Part Two: Definitions and Concepts
The word "polyelectrolytes" is a general term for water-soluble molecules comprised of many repeating units. As the name implies, most such materials of interest to papermakers have a significant level of electical charge. In other words, small ions dissociate from the macromolecule, leaving a net charge associated with the chain. Many polyelectrolytes of interest to papermakers are linear, as in the case of cationic amylose starch. This compound makes up 28% of dent corn starch and 21% of potato starch. These starches are used to make cationic starch for wet-end addition. Many other polyelectrolytes are branched, as in the case of polyethyleneimine (PEI). Also, most starch products contain a majority of branched molecules called amypolypecin. Cationic starch produced from waxy maize is about 100% branched molecules. Soluble aluminum products such as alum and PAC are often considered to be polymeric because of the formation of oxygen bridges between the aluminum ions (olation) during use.
Request from the webmaster: Our goals include brevity and accuracy. Hopefully we have succeeded with the first goal without sacrificing the second. Please let us know right away if you find an error or omition. Also, please indicate points that need a clearer description.
RETURN TO INDEX PAGE OF ENCYCLOPEDIA
This page is maintained by Martin hubbe, Associate Professor of Wood and Paper Science, NC State University, email@example.com .