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Differential scanning calorimetry and thermogravimetric analysis curves were obtained for cotton cellulose in the presence of both flame-retarding and nonflame-retarding compounds and evaluated quantitatively for ΔH, activation energy, total weight loss, and char remaining after pyrolysis. Twenty-three compounds were tested and were found to fall roughly into three groups: (I) those which do not undergo decomposition in the temperature interval in which cellulose decomposes (200-400°C); (II) those which decompose appreciably during or preceding this temperature range; and (III) those which do not interact in any way with cellulose. It was found that, with increasing molar add-on, heat liberated from cellulose decreased for group I, increased for group II, and was not a function of molar add-on for III.A study of the kinetics of decomposition for these systems indicates that, while the majority of reactions proceeded as a pseudo first-order process, there are several exceptions to the trend. As would be expected for a first-order process, activation energy was found to decrease with increasing flame retardancy.Further, it has been observed that the addition to cellulose of any of the compounds from the first two groups lowers the onset temperature of decomposition and the temperature at which the first major weight loss begins. This temperature decrease approaches some type of limiting value for all the compounds, and varies from compound to compound. In addition, a large increase in remaining char results from a very small add-on, and this, too, tends to approach a limiting value as add-on increases. [ABSTRACT FROM PUBLISHER]

The kinetics of the shrinkage of a drawn polyester yam in a number of organic solvents, including toluene, acetonitrile, dimethylformamide (DMF), trichloroethylene, perchloroethylene, and tetrachloroethane, were investigated at several temperatures. The shrinkage process proceeds at a maximum rate after an induction period which is believed to be associated with diffusion of the solvent into the fiber structure. The temperature dependence of the maximum shrinkage rate follows the Arrhenius relationship. Activation energies ranging from 23 to 36 kcal/mol were found for the various solvents, compared to 13 kcal/mol for the shrinkage in the dry state. The equilibrium or final shrinkage values were found to increase linearly with temperature, thereby allowing extrapolation to a zero-shrinkage temperature. This latter value is believe to be an approximation of the glass-transition temperature of the polyester-solvent system. Horizontal shifting along the temperature axis of the curves relating final shrinkage to temperature resulted in a master shrinkage curve for the solvents investigated. The extent of shifting is also believed to be associated with the glass-transition temperature of the system. [ABSTRACT FROM PUBLISHER]