Mini-Encyclopedia of Papermaking Wet-End
Part Two: Definitions and Concepts
Hydrophobic means "water-hating." Chemical groups that tend to make substances hydrophobic include -CH2- chains and rings (hydrocarbons). These substances lack the ability to hydrogen bond and their surface free energy is relatively low. Water does not tend to wet hydrophobic surfaces; rather, the droplets stay beaded up with high values of contact angle. Internal sizing agents such as rosin, ASA, and AKD depend on hydrophobic groups in order to perform their function. The opposite of hydrophobic is hydrophilic, water-loving. Surface-active agents contain both hydrophobic and hydrophilic groups on the same molecules.
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 .