Laser Light-Scattering Study of Novel Thermoplastics. 1. Phenolphthalein Poly(aryl ether ketone)

Abstract

Five different molecular weight phenolphthalein poly(aryl ether ketone) (PEK-C) fractions in CHCl3 were studied by static and dynamic laser light scattering (LLS). The dynamic LLS revealed that the PEK-C samples contain some large polymer clusters. These large clusters can be removed by filtering the solution with a 0.1-μm filter. We found that the persistence length of PEK-C in CHCl3 at 25 °C is ∼2 nm and the Flory characteristic ratio, C∞, is ∼25. Our results showed that 〈Rg2〉z1/2 = (3.50 ± 0.20) × 10-2Mw0.54±0.01 and 〈D〉 = (2.37 ± 0.05) × 10-4Mw-0.55±0.01, with 〈Rg2〉z1/2, Mw, 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 = (2.20 ± 0.10) × 10-4M-0.555±0.015, where D and M correspond to monodisperse species. Using this calibration between D and M, we have determined molecular weight distributions of five PEK-C fractions from their corresponding translational diffusion coefficient distribution.