Title: THERMAL CHARACTERISTICS OF DOUGLAS-FIR BARK FIBER 25 ° TO 250°C

Signature redacted for privacy. Abstract approved: J. D. Wellons, III Douglas-fir bark fiber was isolated from whole bark via three meth-ods: dry, disc-refined and electrically purified (fiber A); pressurized, disc-refined and water washed (fiber B); and mechanically fractionated and alkali extracted (fiber C). These three fiber types wexe used to test the hypotheses that extractives are responsible for the thermal properties of bark fiber from 25 ° to 250°C, and that thermal outgassing can be controlled by the fiber recovery process. Each fiber type was sequentially extracted with benzene, diethyl ether, ethyl alcohol and water. Benzene soluble extractives proved to be the most stable, and ethanol and water soluble extractives the least stable thermally. The ether soluble extractives were only a minor con-stituent of the total extractives. Thus it is speculated that remova