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

The development of coal thermoplasticity during the primary devolatilization region is critical in determining coke structures. The solvent swelling technique was used to study the changes in macromolecular structure 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 characteristics of the coals. The dilatometric and gas permeability properties are discussed in terms of changes in macromolecular structure. The study of the macromolecular structure provides new insight into the development of thermoplasticity and coke structure.