Fickian and Non-Fickian Sorption Kinetics of Toluene in Glassy Polystyrene

Abstract

A gravimetric sorption apparatus is set up to measure solubilities and diffusivities in polymer−solvent systems, especially designed for measurements at low pressures and in glassy polymers. Interval sorption experiments are performed for the system toluene−polystyrene (PS) above and below the glass transition. Sorption isotherms (VLE) are obtained and diffusion coefficients are calculated in the Fickian diffusion region. Below the glass transition, non-Fickian sorption kinetics (sigmoid, two-stage) are observed.

Influence of humidity on the phase behavior of API/polymer formulations

“…The water sorption in pure PVP, PVPVA64 and PVAc as well as in the formulations considered was measured at 25°C by a gravimetric method using a magnetic suspension balance [34]. This balance measures the weight of an API/polymer sample as a function of the temperature and the partial pressure of water in a measuring cell.…”

Residual Monomer Reduction in Polymer Latex Products by Extraction with Supercritical Carbon Dioxide

“…Krüger and Sadowski (2005) (Zwolak et al, 2005). The amount of moles of monomer added to the autoclave was accurately known (see section 'Materials and methods').…”

Phase equilibria and diffusion coefficients in the poly(dimethylsiloxane)+n-pentane system

“…1). Further data analysis is carried out as described by Krüger and Sadowski [4]. However, for the calculation of the film thickness of the swollen polymer d one-dimensional swelling is assumed due to the polymers ability to swell only towards the top of the glass bucket:…”

“…Pressure decay [3] and sorption measurements, either gravimetric [4,5] or piezoelectric [6], are widely used to determine both properties simultaneously. Inverse gas chromatography (IGC) is mostly used to determine the activity coefficients at infinite dilution [7], but was also extended for measurements at finite concentration [8].…”

“…The equipment, the experimental procedure and the data analysis have been previously described [4] and are therefore only briefly discussed here.…”