Characterization of Engineering Plastics Plasticized Using Supercritical CO₂.

Area of Science:

• Materials Science
• Polymer Engineering
• Chemical Engineering

Background:

• Traditional molding processes for engineering plastics often require high temperatures, potentially degrading polymer properties.
• Supercritical fluids, like carbon dioxide (CO2), offer alternative processing methods due to their unique solvating and swelling capabilities.
• Investigating supercritical CO2 for plasticizing engineering plastics at lower temperatures is crucial for developing advanced material processing techniques.

Purpose of the Study:

• To evaluate the physical and chemical property changes in engineering plastics after processing with supercritical CO2.
• To assess the feasibility of using supercritical CO2 for low-temperature plasticization and molding of engineering plastics.

Main Methods:

• Engineering plastic test pieces were prepared using a standard molding process.
• Samples were plasticized using supercritical CO2 at temperatures below their glass-transition points.
• Physical properties (mechanical strength, surface roughness, contact angle) and electrical properties (rate of charging) were measured.

Main Results:

• Supercritical CO2 treatment plasticized amorphous polymers without significant changes in molecular weight.
• Mechanical strength decreased significantly post-treatment, despite unchanged molecular weight.
• Surface roughness and contact angle showed slight increases, while electrical properties, including the rate of charging, decreased substantially.

Conclusions:

• Supercritical CO2 processing can plasticize engineering plastics at sub-glass-transition temperatures.
• This method alters material properties, notably reducing mechanical and electrical performance.
• The findings suggest potential for a novel, low-temperature molding process using supercritical CO2, tailored to specific property requirements.