Using a Gravimetric Analyzer in Polymer Membranes

Measuring the rate of moisture and transport of vapor through polymeric packaging media with gravimetric analyzers is vital in a variety of industrial and commercial sectors. The effects are felt most by the food and beverage industry and the pharmaceutical sector, as these are industries where products may be subject to phase and stability changes due to chemical variations.

For instance, dosage form tablets may succumb to amorphic phase changes when they are permeated by microscopic levels of water. Naturally, this affects their efficacy and shelf life. Polymeric packaging is designed to resist moisture and vapor permeation to maximize the longevity of products that are moisture-sensitive in nature. This also ensures they meet the necessary regulatory standards for distinct sectors.

This blog post aims to outline a study that was designed to determine water content isotherms with diffusion measurements to characterize changes in water mobility behavior of polymer films at high water concentrations.

Testing Concentration Dependent Mobility of Water with a Gravimetric Analyzer

This study used an IGAsorp gravimetric analyzer to determine the isothermal concentration of water vapor and the chemical diffusion coefficient of two treated and untreated polymer films. The isothermal concentration of water vapor refers to changes in water concentration within the polymer film as a function of temperature. The chemical diffusion coefficient is based on Fick’s law of diffusion, and was calculated as a measure of temperature and concentration that depends on the distinct properties of the sample.

Each of these metrics were used to determine the transmission rates of water through polymer membranes of varying thicknesses. They were used in tandem to provide a detailed assessment of changes in microscopic water mobility based on concentration. This provided new data regarding relative changes in mobility as a function of concentration.

It also revealed that the untreated polymer achieved a water content that was almost 35% higher when compared with the treated sample. In addition, there were significant differences between the polymers in their diffusive behavior until a higher level of humidity (>70%), where the trends were then similar.

Gravimetric Analyzers from Hiden Isochema

One of the leading global manufacturers of dynamic vapor sorption analyzers and gravimetric sorption analyzers is Hiden Isochema. The IGAsorp DVS analyzers are popular in both academic as well as industrial sectors, finding use within hundreds of R&D and process laboratories. Key areas of application include: pharmaceutical, biotech, polymers, packaging, natural materials, building and construction materials (cement, timber, insulation, adhesives), electronics, and fuel cells (proton exchange membranes).

This information has been sourced, reviewed and adapted from materials provided by Hiden Isochema.

For more information on this source, please visit Hiden Isochema.