Orientation in uniaxially drawn polystyrene plasticized by CO₂ sorption

Abstract

SYNOPSISUniaxial drawing experiments of the polystyrene films plasticized by a sorption of compressed CO, gas at pressures up to about 18 MPa were carried out with strain rates c of 0.0290 and 0.0079 s-l. The drawing was performed successfully with draw ratio X up to 4 at the temperatures of 308.15, 318.15, 328.15, and 338.15 K. The Hermans orientation function f of the drawn samples was determined from the dichroic ratio measured by an infrared spectrophotometer. While f value increases with increasing c or A, it decreases with increasing C 0 2 pressure or temperature.

Glass Transition Temperature of Polystyrene with Compressed Carbon Dioxide.

“…The in situ uniaxial drawing of PS films in CO2 can not be done until PS films are plasticized with CO2 gas. Hence information on Tg of PS has been given from the possible drawing of films under some pressure and temperature conditions [9]; it is suggested that Tg of PS in CO2 above 10MPa is lower than 308.2K. This idea is consistent with the results obtained by Condo et al from the creep compliance method [6].…”

“…By using this apparatus, uniaxial drawing experiments of PS films in CO2 have been carried out up to about 18MPa at several temperatures to study the effects of strain rates, draw ratio, temperature, and pressure on the orientation in uniaxially drawn PS films [9]. In addition, gas permeability in the uniaxially drawn PS films has been measured [10]; some improvements of gas permeability coefficients of gases such as CO2, O2, and N2 have been observed.…”

Generation of microcellular poly(methyl methacrylate) by compressed gases

“…In a previous paper [2], we have constructed an in situ uniaxial drawing apparatus for polymeric materials in compressed gases up to 30 MPa. We have studied the orientation in uniaxially-drawn polystyrene (PS) plasticized by COz sorption to get some insight into the effects of temperature, pressure, strain rate, and drawn ratio on the orientation of films [3]. Furthermore, we have reported that no appearance change except for the dimensions was found and no micro void was detected in PS films after uniaxial drawing in COz and a rapid expansion of C 0 2 gas in the temperature and pressure ranges of 308.15-338.15K and 5.5-18MPa [2].…”