Electron Microscopic Investigation of the Structure and Morphology of Syndiotactic Polypropylene.

We have investigated the temperature dependence of the streaking that we had previously discovered in electron-diffraction patterns of single crystals of syndiotactic polypropylene. This h10 streak is essentially absent for crystallization temperatures higher than 105C, but has fully replaced all discrete reflections for growth below ca. 70C. This behavior confirms our newly proposed interchain lattice for syndiotactic polypropylene, is inconsistent with the long-standing original unit cell, and indicates progressive packing disorder as growth rate increases. These phenomena are interpreted in terms of different degrees of incorporation of right- and left-handed helical molecules within the crystal lattice.