Synthesis and Foaming of Water Containing Activated Carbon-Nano/Microparticulate Polystyrene

A novel method to increase thermal efficiency infrared absorption and bulk density of polystyrene foams.

The Need

Blowing agents create a cellular structure from a liquid plastic resin and, in certain cases, function as an insulating component of the foam. Hydrogen-containing chlorofluorocarbons and fluorocarbons are common blowing agents in the foam industry for extrusion forming of Polystyrene foam. However, it is known that these blowing agents cause ozone-depletion. Currently, hydrocarbons and carbon-dioxide are the most appealing alternatives, but it is difficult to produce foams from these compounds. It is critical to develop environmentally-friendly and inexpensive blowing agents that produce quality foams.

The Technology

Researchers at The Ohio State University, led by Dr. L. James Lee, have developed foam extrusion process that uses water as a co-blowing agent for CO2 to control the bulk density, bubble size, and expansion ratio. The method prepares water expandable polystyrene (PS)-activated carbon (AC). AC pre-saturated with water is introduced to the styrene monomer, which forms water-in-oil inverse emulsion. Spherical water/AC PS beads are obtained through suspension polymerization. By extrusion foaming process, a PS/AC composite foam with ultra-low density is produced.

Commercial Applications

  • Thermal Insulation
  • Packaging
  • Fire-Retardant Materials
  • Energy Recovery
  • Cushions
  • Absorbents
  • Scaffolds for cell attachment and growth

Benefits/Advantages

  • Produces foams with ultra-low bulk density
  • Foams produced by this method have greater thermal insulation efficiency and infrared absorption
  • Expandable PS/AC beads prevent quick escape of water during early stage of extrusion foaming process

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