Conformational transition in poly(p-tert-butylstyrene)

In recent years many reports have arisen of temperature-induced conformational transitions in some synthetic polymers in dilute solutions. The phenomenon has been characterized by a discontinuity in the change of some physical properties of polymers (such as intrinsic viscosity and refractive index increment) with temperature in dilute solutions. Discontinuity has also been found in the change of intrinsic viscosity with the composition of solvent mixture and has been interpreted as a conformational change of the polymer. In some polymers, conformational transitions have also been evidenced by other techniques such as light-scattering, NMR, and UV spectrometry and by dipole moment measurements. Dilute solution properties of poly(p-tert-butylstyrene) exp 16 (PTBS) have been studied. The variation of intrinsic viscosity and refractive index increment with temperature for PTBS in good solvents are presented. Graphs. 20 ref.--AA