Precipitation of polystyrene from toluene with HFC-134a by the GAS process
- National Tsing Hua Univ., Hsinchu (Taiwan, Province of China). Dept. of Chemical Engineering
Polystyrene is a versatile thermoplastic material used in a wide range of applications. Because of the large quantity of polystyrene produced in the world, recycling of waste polystyrene is essential in order to make this industry sustainable. Precipitation of polystyrene from toluene solution using HFC-134a as antisolvent was investigated. In this gas antisolvent (GAS) precipitation process, the pressurized HFC-134a was dissolved into a 20-g toluene solution containing 5 and 10 wt % polystyrene. The pressure required to expand toluene and cause precipitation of polystyrene by HFC-134a was observed to be much lower than that required by the frequently used antisolvent carbon dioxide. At a temperature of 293 K and a pressure of 5.17 bar, 67 and 74.5% yields were obtained for holding times of 50 and 120 min, respectively. The cloud-point pressure was found to be linearly dependent on temperature. Almost the same yield was obtained for any arbitrary combination of temperature and pressure having the same binary volume expansion. The volume expansion was found to be the major factor influencing yield. The operation with a higher pressure and a lower temperature would result in a higher yield.
- OSTI ID:
- 624346
- Journal Information:
- Industrial and Engineering Chemistry Research, Vol. 37, Issue 5; Other Information: PBD: May 1998
- Country of Publication:
- United States
- Language:
- English
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