THE MACROMOLECULAR NATURE OF BITUMINOUS COAL

Considerable insight into the macromolecular state of coal has been obtained by examining the optical anisotropy of untreated solvent-swollen, and chemically derivatized thin sections of coal. From the effect of pressure on the optical anisotropy, and from the rate and degree of recovery after release of pressure, it was found possible to determine whether the coal is in a plastic or rubbery state, whether a rubbery state is cross-linked and how mobile the macromolecular chain segments are. The experimental technique utilized for this work was transmission optical microscopy in polarized light of uncontaminated thin sections of vitrinite from a bituminous coal.