Morphological Studies of Semicrystalline Poly(2,6-dimethylphenylene oxide)

A sample of poly(2,6-dimethylphenylene oxide) (PPO) has been crystallized by exposure to 2-buta­none (MEK) vapor. This sample has been investigated by wide and small angle x-ray scattering (WAXS and SAXS), differential scanning calorimetry (DSC), and light-scattering techniques. The WAXS and DSC experi­ments reveal a maximum crystallinity of about 30%. The SAXS, analyzed according to the linear paracrystal model of Hosemann, indicates a high degree of order in the superlattice with an average crystal lamellar thickness of 38 A. Extensive peak broadening occurs in the W AXS curve arising from crystal lattice distortions or defects. These dis­tortions or defects most probably are a consequence of the removal of solvent molecules from the lattice during the drying process. The light-scattering studies show a rodlike morphology apparently made up of fibrous bundles. The exact nature of the structures responsible for the observed light-scattering patterns cannot be conclusively demon­strated.