The physical and chemical changes occurring during heating cellulose, thermal reaction of pentachlorophenol and its derivatives, and accessibility studies of cellulosic materials

The overall objectives of this study were to determine the effects of heating on cellulose and on pentachlorophenol. Both of these materials are very important to the Forest Products Industries.; Cellulose is the major constituent of all plants including wood and cotton. The chemical and physical properties of cellulose can be modified by using the low temperature thermal pretreatment method.; Pentachlorophenol is used in wood to protect wood from biological degradation. Under high temperatures and alkaline conditions, pentachlorophenol can be converted into highly toxic compounds such as dioxins and furans.; In this study, the thermal reactions of pentachlorophenol and its derivatives were characterized by TGA, FT-IR, and HPLC. The chemical properties of thermal treated cotton cellulose were investigated by determination of total available glucose (TAG), FT-IR spectroscopy, and enzymatic hydrolysis. The microporous properties of treated and untreated cotton cellulose and the accessibility of cellulosic materials were evaluated by the solute exclusion method.; The major thermal reaction of salts of pentachlorophenol at 350{dollar}spcirc{dollar}-500{dollar}spcirc{dollar}C involves the ortho positions of two pentachlorophenate molecules which undergo a condensation reaction, leading to octachlorodibenzo-p-dioxin (OCDD) formation. The maximum OCDD recovery from pentachlorophenate salts was found to be 88% at 500{dollar}spcirc{dollar}C. For low temperature treated cotton cellulose, chemical analysis indicates only minor changes in the molecular structure and FT-IR spectra also show a slight increase in the carbonyl group. However, the major thermal effects on the cotton cellulose between 160{dollar}spcirc{dollar}-200{dollar}spcirc{dollar}C involve changes in surface area and in pore structure. This in turn affects enzymatic hydrolysis rates, water properties, and dimensional stability. In the accessibility study, the accessibility of cellulosic materials is shown to vary according to the degree of pretreatment of the cellulosic materials.