Polymer morphology control with crystallization during polymerization

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Most natural polymers are crystalline when polymerized. They crystallize concurrently with the polymerization reaction. We have studied crystallization during solution polymerization to control polymer morphology. In 1987, we found and reported that needle-like poly (p-oxybenzoyl) (POB) whiskers, which were single and extended chain crystals could be formed under certain polymerization conditions. This was the first polymer whisker obtained by polycondensation reaction and showed a new morphological processing for intractable polymers. We have also manifested the formation mechanism of POB whiskers. In this study, we investigated the basic problems on mechanism of crystallization during solution polymerization to control the nascent morphology. The isothe formation mechanism of needle crystals, the solid state polymerization mechanism of oligomers in stacking lamella and the relation between formation rate and crystallization rate of oligomers by used solvents were studied. In final, we elucidated the influence for the nascent morphology'with polymerization conditions. Furthermore, we applied this method for poly (oxy-2, 6-naphthalenediyl carbonyl) and poly (azomethine) and succeeded in the synthesis of the whisker. Thus, we developed the morphology control of polymers by crystallization method concurrent with solution polymerization.