X-RAY STUDIES OF STRUCTURAL ORDERING CHANGES ON ANNEALING A NON-CRYSTALLINE POLYCARBONATE

Structural ordering changes of a non-crystalline polycarbonate (trade name 'Bistan AW') were investigated. Three interference halo signals were recorded on the X-ray diffraction patterns at reflection angles equal to θ1 = 3.1° (d = 14.3 A ̊), θ2 = 8.5° (d = 5.2 A ̊), and θ3 = 12.7° (d = 3.5 A ̊). The areas of peaks at θ1 were found to decrease and those at θ2 to increase with increasing the time of annealing the previously melted polycarbonate samples at a temperature of 190°C. It was concluded that morphological changes were taking place in the polycarbonate prior to its thermal crystallization. These changes may be explained by assuming the existence of two morphological forms of structural ordering in non-crystalline polycarbonate macromolecules. On annealing, macromolecules belonging to the cis-form having a lower degree of structural ordering most probably tend to straighten out and assume a zigzag structure, i.e. all-trans conformation. After straightening out of the chains, these macromolecules link up with areas exhibiting a much higher degree of structural ordering and most probably exist in the trans-form. © 1979.