Studues on morphology conrtrol of polymer crystals during polymerization IV. Molecular weight change during poly(p-oxybenzoyl) whisker formation.

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  • 重合過程を利用した高分子結晶の形態制御に関する研究　第４報　ポリ（ｐ‐オキシベンゾイル）ウィスカーの生成過程における重合度変化
  • ポリ p オキシベンゾイル ウィスカー ノ セイセイ カテイ ニ オケル ジュ

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Molecular weight changes during poly (p-oxybenzoyl) whisker formation from p-acetoxybenzoic acid in liquid paraffin were studied. Our electron microscope observation suggestd that the needle crystals in the very early stage of polymerization consist of stacks of oligomer lamellae. Here, the degree of polymerization of precipitated oligomers was found to be about 8, from analysis of oligomers dissolved in liquid paraffin by HPLC method. Furthermore, transesterification in the interlamellar regions starts as soon as crystals precipitate. The average DP of whiskers obtained with 3 min after crystal precipitation increases from 8 to 48. These crystals show fibrillation by crushing of whiskers in liquid nitrogen or etching in KOH solution. This fact indicates that reorganization into extended chain crystals occurs accompanied by the increase of DP. On the other hand, DP of the eventual whiskers increased by 1860. That is, the average molecular length exceeds 1μm. The formation of such high molecular weight polymers in the solid state polymerization is caused by the closely packed structure of the end groups.

Journal

  • KOBUNSHI RONBUNSHU

    KOBUNSHI RONBUNSHU 47 (7), 583-589, 1990

    The Society of Polymer Science, Japan

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