ポリアクリロニトリル無配向フィルムの無定形領域の微細構造分布

抄録

The detailed fine structure of amorphous region in unoriented polyacrylonitrile (PAN) film was studied by analyzing, according to the method proposed by the authors, the dynamic loss tangent (tanδ)-temperature curve. If a major component of solvents remaining in the solution at the instance when the solution solidifies by evaporating solvent or by adding non-solvent was poor solvent for PAN, an amorphous region with a strong intermolecular interaction (i.e., a closely-packed region) (region 1) had a tendency to be produced from the solidified gel. If a major component was good solvent in that case, an amorphous region with a weak interaction (i.e., a loosely-packed region) (region 2) appeared. Region 1 had a comparatively uniform distribution with respect to the degree of molecular packing (packing density) (i.e., small heterogeneity index n_t), whereas region 2 had a broad distribution (i.e., large n_t). With increase in the amount of solvent (for example, N, N′-dimethylformamide (DMF)) C_D absorbed after film formation, n_t for region 1 increased, but n_t for region 2 decreased. Region 1 transformed to region 2 in the range C_D of DMF>14wt%. Region 2 transformed to region 1 by annealing in wet state. Introduction of co-monomer (methylacrylate) increased the relative amount of region 2 and decreased n_t of region 2.