| Abstract: | The crystal structure of poly(p-xylylene), as polymerized, is the α form. This transforms irreversibly to the β from by annealing or drawing. To clarify the mechanism of this transition, structural changes of the α and β crystals were examined with a high-temperature stage in the electron microscope. Two high-temperature phases, β1 and β2, were found and their structures were analyzed. In these structures lattice distortions due to rotational and translational motions of chains are in troduced, especially in the β2 form. The α → β transition is induced through such a disordered phase. The statistical arrangement of a molecule in the β-form unit cell results from freezing the disorder in the high-temperature phases. |
