DETERMINATION OF MOLAR MASS-DISTRIBUTION OF POLY(TETRAFLUOROETHYLENE)

High-temperature static and dynamic laser light scattering characterization of polytetrafluoroethylene in perfluorotetracosane has been accomplished after solving the following experimental difficulties: (1) constructing a high-temperature laser light scattering spectrometer which can be operated at a temperature as high as 340-degrees-C, (2) developing a new all-glass apparatus for dissolving and filtering, (3) measuring the refractive index increment of polytetrafluoroethylene in perfluorotetracosane at 325-degrees-C, and (4) establishing a scaling relation between the molecular weight (M) and the translational diffusion coefficient at both infinite dilution and the zero scattering angle from only two broadly distributed polytetrafluoroethylene samples so that we can convert the translational diffusion coefficient distribution to the molecular weight distribution. This paper presents a summary of our published results of the characterization Of poly(tetrafluoroethylene) , which emphasizes the experimental details of high-temperature laser light scattering and the principle of the transformation from a translational diffusion coefficient distribution to a molecular weight distribution.