Presenter's Name(s)

Xiangxiao YaoFollow

Primary Faculty Mentor Name

Linda Schadler

Status

Graduate

Student College

College of Engineering and Mathematical Sciences

Program/Major

Mechanical Engineering

Primary Research Category

Engineering & Physical Sciences

Presentation Title

Relationship Between Gas Solubilities/Diffusivities and Dielectric Properties of Gas Infused Polymer System under High Temperatures and High Pressures

Time

12:00 PM

Location

Frank Livak Ballroom

Abstract

Dissolving supercritical fluids (SCFs) or gas in polymers is widely used in processes. Many properties such as rheological properties, plasticization behaviors, glass transition, and crystallization of polymers can be directly affected by the solubility and diffusivity of the SCFs or gas in the polymers. There are several methods to obtain the diffusivity and solubility such as gravimetric, manometric, spectroscopic, and chromatographic methods. However, these measurements are either expensive, complex, and/or sensitive to an electromagnetic field. In order to overcome these disadvantages in the incumbent measurement techniques, a new method was investigated to determine the solubility and diffusivity of gas/SCF in polymers using a dielectric property. In this study, we hypothesized that the solubility and diffusivity of dissolved gas in polymers can be obtained from the dielectric constant of each component and the mixture and developed a new device for capacitance measurements. To calculate dielectric constants, we first determined the capacitance of pure gas and polymer matrix, respectively at given temperature and pressure. Then, we determine that of the mixture after saturating the matrix with the dissolved gas. CO2 is chosen as the gas because it is an environmentally benign gas, which can be used as a blowing agent with relatively a high solubility in various polymers and is widely used in polymer industry. Polystyrene is chosen as the matrix since it is amorphous and can dissolve a plenty amount of CO2 compared to other polymers. Results showed that the capacitance of the mixture increases with the amount of dissolved CO2 indicating that there is a direct relationship between the dissolved amount of CO2 and the dielectric constant of the mixture, and eventually, the solubility of CO2 can be estimated.

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Relationship Between Gas Solubilities/Diffusivities and Dielectric Properties of Gas Infused Polymer System under High Temperatures and High Pressures

Dissolving supercritical fluids (SCFs) or gas in polymers is widely used in processes. Many properties such as rheological properties, plasticization behaviors, glass transition, and crystallization of polymers can be directly affected by the solubility and diffusivity of the SCFs or gas in the polymers. There are several methods to obtain the diffusivity and solubility such as gravimetric, manometric, spectroscopic, and chromatographic methods. However, these measurements are either expensive, complex, and/or sensitive to an electromagnetic field. In order to overcome these disadvantages in the incumbent measurement techniques, a new method was investigated to determine the solubility and diffusivity of gas/SCF in polymers using a dielectric property. In this study, we hypothesized that the solubility and diffusivity of dissolved gas in polymers can be obtained from the dielectric constant of each component and the mixture and developed a new device for capacitance measurements. To calculate dielectric constants, we first determined the capacitance of pure gas and polymer matrix, respectively at given temperature and pressure. Then, we determine that of the mixture after saturating the matrix with the dissolved gas. CO2 is chosen as the gas because it is an environmentally benign gas, which can be used as a blowing agent with relatively a high solubility in various polymers and is widely used in polymer industry. Polystyrene is chosen as the matrix since it is amorphous and can dissolve a plenty amount of CO2 compared to other polymers. Results showed that the capacitance of the mixture increases with the amount of dissolved CO2 indicating that there is a direct relationship between the dissolved amount of CO2 and the dielectric constant of the mixture, and eventually, the solubility of CO2 can be estimated.