An investigation of selected factors that influence hardwood wettability

Abstract

Wettability of sanded and non-sanded transverse and tangential sections of 22 southern hardwoods species was judged by measurement of contact angles using phenol formaldehyde resins. As expected, contact angle values on transverse sections were higher than those on tangential sections for both sanded and non-sanded surfaces. On sanded surfaces, hackberry had the highest mean contact angle (64.7°), and black oak had the lowest mean contact angle (50.1°). On non-sanded surfaces, winged elm had the highest mean contact angle (59.1°), and sweetgum had the lowest mean contact angle (45.9°). In addition, 4 of the 22 species (southern red oak, sweetgum, white oak, and post oak) were selected to investigate the effect of oven-drying, air-drying, and free-drying on wettability. The mean transverse contact was 2.1°-29.0° and 5.l°-31.5° higher than radial and tangential values, respectively. The contact angle pattern typically displayed for a given species and plane was generally oven-dry > air-dry > freeze-dry. The species pattern for most methods and planes was: sweetgum > white oak > post oak > southern red oak. White oak and post oak have similar contact angle values.

Citation

Shupe, Todd F.; Hse, Chung-Yun; Wang, Wan H. 2001. An investigation of selected factors that influence hardwood wettability. Holtzforschung 55(5):541-548