Morphology and crystallinity of particles formed from dilute solutions of poly(vinyl alcohol-b-acrylonitrile), poly(vinyl alcohol) and polyacrylonitrile

The morphology of agglomerates and particles of poly(vinyl alcohol-b-acrylonitrile), poly(vinyl alcohol) (PVA) and polyacrylonitrile (PAN) formed from their dilute solutions and the variation of the morphology with the composition of the block copolymers were examined using transmission electron microscopy. The crystalline nature of these particles was studied by an electron diffraction method. Electron diffraction for copolymers containing AN lower than 30 wt% mainly showed a single-crystal diffraction pattern of the PVA component. With the copolymer containing 38.90 wt% AN, a mixed pattern of a blend of PVA polycrystal and PAN polycrystal as well as a PVA single-crystal pattern were simultaneously observed.