Laser Light-Scattering Study of Novel Thermoplastics. 2. Phenolphthalein Poly(ether sulfone) (PES-C)

Five narrowly distributed fractions of phenolphthalein poly(ether sulfone) (PES-C) were studied in CHCl 3 by both static and dynamic laser light scattering (LLS) at 25 °C. The dynamic LLS showed that the PES-C samples contain some large polymer clusters as in previously studied phenolphthalein poly(ether ketone) (PEK-C). These large clusters can be removed by a 0.1-μm filter. Our results showed that 〈 R g 2 〉 z 1/2 = (3.35 ± 0.13) × 10 -2 M w (0.52 ± 0.03) and 〈 D 〉 = (2.26 ± 0.02) × 10 -4 M w -(0.54 ± 0.03) with 〈 R g 2 〉 z 1/2, M w, and 〈 D 〉 being the z -average radius of gyration, the weight-average molecular weight, and the z-average translational diffusion coefficient, respectively. A combination of static and dynamic LLS results enabled us to determine D = (2.45 ± 0.04) × 10 -4 M -(0.55 ± 0.05), where D and M correspond to monodisperse species. Using this scaling relationship, we have successfully converted the translational diffusion coefficient distribution into the molecular weight distribution for each of the five PES-C fractions. The weight-average molecular weights obtained from dynamic light scattering have a good agreement with that obtained from static laser light-scattering measurements.