SOME ASPECTS OF CHANGES IN THE MACROMOLECULAR STRUCTURE OF COALS IN RELATION TO THERMOPLASTIC PROPERTIES

The development of coal thermoplasticity during the primary devolatili zation region is critical in determining coke structures. The solvent swelling technique was used to study the changes in macromolecular str ucture of four coals of different rank (902 to 203 in the British Coal classification scheme) during carbonization to temperatures up to 600 degrees C. The results were compared with the thermoplastic character istics of the coals. The dilatometric and gas permeability properties are discussed in terms of changes in macromolecular structure. The stu dy of the macromolecular structure provides new insight into the devel opment of thermoplasticity and coke structure.