From waxes to polymers - Crystallography of polydisperse chain assemblies

Exploiting available single-crystal diffraction patterns from individual microareas, electron crystallography has characterized rectangular layer chain packing for polydisperse extended chain polymethylene chain assemblies. From this work, one can appreciate how these chain assemblies form stable solid solutions and also how they may phase separate. It is clear that two types of stable solid solution are formed-one that is lamellar and one that is "nematocrystalline." Respective examples are wax fractions with narrow chain length distributions and chain-extended, low molecular weight polyethylene.