16.動的粘弾性に基づく石炭の熱可塑性および再固化反応の解析

抄録

Effects of operational variables including heating rate and oscillation frequency on the dynamic viscoelasticity of four kinds of bituminous coals were examined during heating up to 823K under the flow of nitrogen. The complex viscosity, η^*, was used to evaluate the softening and re-solidification characteristics of the coals. It has been found that the onset temperature of softening is not varied with the heating rate, whereas the minimum η^* values and temperatures at which the η^* show minimum values are appreciably influenced by heating rate. The early stage of coal softening is likely to be a physical melting process but the later stage of softening and the solidification are controlled by the chemical reaction process. The solidification process was also studied under isothermal conditions. Gel time, which is a measure of reaction rate for solidification, has been utilized to determine the apparent activation energy of the solidification process. The activation energies of coal samples were approximately 200kJ/mol, much higher than those of thermosetting polymers (vinyl ester resin (VER)^<1)>, diglycidylether of bisphenol A (DGEBA)/trimethylolpropane triglycidylether (TMP)^<2)>).