VISCOSIMETRIC STUDY OF POLY(2',5'-DIALKYL-P-TERPHENYLENE TEREPHTHALATE) - STATISTICAL SEGMENT LENGTH AND CONFORMATIONAL TRANSITION

The conformational behavior in solution and in the temperature range 30-85-degrees-C for the title polyester was investigated using simple viscosimetric methods. The obtained unperturbed dimensions parameter and the statistical segment length have shown that this polyester behaves in solution as a rigid polymer. Comparison with the persistence length values obtained for related polymers indicates a significant increase in rigidity, caused by the introduction of the terphenyl unit. The temperature dependence of both the unperturbed dimensions and the persistence length indicates the existence of a conformational transition at 60-degrees-C. These results are in good agreement with those obtained in the solid state, showing the existence for this polymer of a memory effect.