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Ternary systems involving rod/coil/solvent: poly( p ‐benzamide)/poly(2‐phenylene(5‐benzimidazole)‐isophthalamide)/dimethylacetamide + LiCl
Author(s) -
Bianchi Estella,
Marsano Enrico,
Costa Camilla,
Conio Giuseppina,
Bisbano Stefania
Publication year - 1997
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1997.021980425
Subject(s) - dimethylacetamide , benzimidazole , polymer chemistry , phenylene , diluent , chloroformate , formamide , phase diagram , ternary operation , mesophase , chemistry , liquid crystal , ternary numeral system , polymer , phase (matter) , solvent , materials science , organic chemistry , optoelectronics , computer science , programming language
The ternary diagram involving a rigid polymer [poly( p ‐benzamide) (PBA)], a flexible polymer [poly(2‐phenylene(5‐benzimidazole)isophthalamide) Structure‐based name: poly(benzimidazole‐2,5‐diyl‐iminoisophthaloylimino‐1,4‐phenylene). (PABI)] and a diluent composed of dimethylacetamide plus 3 wt.‐% LiCl (DMAc/3LiCl) was investigated. Addition of PABI to PBA solutions increases the critical volume fraction value at which a nematic phase is observed. The line connecting these values at different PBA/PABI ratios divides a region of isotropic solutions from a biphasic area. No case of a single anisotropic phase was observed. A peculiarity of the diagram is that the composition of the anisotropic phase in the biphasic region lies on the PBA‐diluent axis when the molecular weight of PABI is relatively high, whereas it shows a small content of PABI when its molecular weight is low. This result has recently been theoretically predicted by considering the existence of anisotropic interactions in the mesophase. The agreement between theoretical and experimental phase diagrams is fairly good.