Critical Processing Conditions of a Specific Ternary System-Molecular Composite

The phase relationship and thus the critical processing conditions, e.g., concentration and temp, 97 MSA3 CSA, a rigid rod-like polymer poly- para-phenylenebenzothiazole, PBT, and a flexible chain polymer poly-2,56 benzimidazole, AB-PBI was studied by means of cross-polarized light microscopy and small-angle light scattering SALS technique. Critical concentration points were observed and determined for all four ABPBIPBT blends studies. When the polymer concentration was higher than the critical concentration, the ternary solution segregated into coexisting anistropic and isotropic phases. The anisotropic phase, containing practically only rigid rod-like PBT polymers, showed distinct nematic features both in the solution and in processed film, while the isotropic phase retained all the ABPBI molecules. Excellent agreement between the experimental and the theoretical binodial curve for the isotropic phase in the phase diagram lend strong support to Florys recent theory concerning the behavior of mixtures of rigid rod-like polymers with flexible coil polymers. The nematic isotropic transition temperature, IN-I, was also determined for various ABPBIPBT blends at various concentrations. This study provides the insight of the important parameters such as concentration, temperature, composition, and rod-like polymer orientation of the ternary solution which are necessary for processing of PBPBIPBT molecular composite films.