Structure and properties of poly(ethylene‐co‐chlorotrifluoroethylene) and polyvinylidene fluoride exposed to water, hydrochloric acid, hydrobromic acid and tetrachloroethylene

Abstract

The transport of water, hydrochloric acid, hydrobromic acid and tetrachloroethylene in an poly(ethylene‐co‐chlorotrifluoroethylene) and polyvinylidene fluoride were studied at 70°C by the sorption/desorption technique. The effects on the structure and mechanical properties were studied using size‐exclusion chromatography, infrared spectroscopy, differential scanning calorimetry and tensile testing. Solute concentrations in the polymers indicated that both the water and HCl/HBr components diffused into the polymers on exposure to acid solutions. The calculated water contents of the diffusing acids generally differed from the water content in the solution. The ratio of water content in the diffusing acid to that in the surrounding acid solution was generally a function of the relative vapor activity of water and HCl/HBr. It was possible to describe the 35%HCl and 47%HBr desorption data using a two component model. It was here assumed that the water and HCl/HBr diffused separately, each having its own constant diffusion coefficient. The water diffusivity was obtained from the pure water system, and this allowed the HCl/HBr diffusivity to be calculated. It was found that the diffusivity decreased, in a non‐simple way, as a function of solute size. The exposure to solute did not lower the molar mass of the polyvinylidene fluoride. Differential scanning calorimetry indicated the development of low‐melting point polyvinylidene fluoride crystals during the exposure to all solutes. This seemed to be a consequence of the long‐term exposure (175 to 376 days) at 70°C. The long‐term exposure stiffened several of the polyvinylidene fluoride resins and occasionally made them less ductile. The poly(ethylene‐co‐chlorotrifluoroethylene) also became stiffer, but it was otherwise unaffected as far as observation by the other available techniques was concerned.

Is survival of patients with atherosclerotic renal artery stenosis affected by different predictors compared to other atherosclerosis manifestations?

“…The diffusion of water in the vinyl ester was also concentration dependent (Table III). The diffusion coefficient for hydrochloric acid, shown in Table III, is an average diffusion coefficient representing both the diffusion of water and that of hydrochloric acid molecules 22…”

Transport and adhesion properties of an unlined and a liquid‐crystalline polymer–lined vinyl ester thermoset exposed to severe environments

“…The diffusion coefficient for hydrochloric acid, shown in Table III, is an average diffusion coefficient representing both the diffusion of water and that of hydrochloric acid molecules. 22 Interestingly, the coefficients of diffusion of water and methanol in FEP and in the vinyl ester were of the same order of magnitude. The transmission rates of water and methanol in FEP, however, were about three orders of magnitude lower than those in the vinyl ester because of the extremely low equilibrium concentrations in FEP.…”

Effect of porosity and hydrostatic pressure on water absorption in a semicrystalline fluoropolymer

“…Semicrystalline fluoropolymers are often used as protective coating material in wet environments, which make it important to have a good knowledge of its sorption characteristics to assess the long-term properties of polymer structures. Only a few works have reported water sorption in this kind of polymers [18,19] and none have considered hydrostatic pressure or porosity effects.…”