PPO/PSƒ|ƒŠƒ}[ƒAƒƒC‚Ìp-ƒË-T“Á«‚Æó‘ÔŽ®
A Study on p-v-T Properties and Equation of State of the Polymer Alloys Polyphenylene Oxide (PPO)/Polystyrene (PS)
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Sato, Sadao / Itoga, Akira / Ito, Kimitaka / Oyamagi, Yasushi
A p-v-T device for determining the specific volume of solid and liquid polymer alloys as a function of pressure (up to 200MPa) and temperature (30-350Ž) has been constructed. It is a plunger type which consists of a plunger, cylinder, heater and laser displacement meter. The measurement accuracy of the device was within }2-3%. The p-v-T properties were determined by the isothermal testing method. We have discussed the effects of the mixing ratio on p-v-T properties of polymer alloys and the empirical equation of state. The empirical equation of state for amorphous polymers such as PPO, PS and its alloys is presented as follows :
v(p, T)=v0(0, T0) + (ƒ°AiTi+pƒ°BiTi+p2ƒ°CiTi)
Here, v is specific volumes as a function of pressure and temperature, v0 is specific volume at atmospheric pressure (p=0) and room temperature (T0). The Ai (i=0-3), Bi and Ci (i=0-1) are coefficients of the p-v-T characteristic each polymers. The values of these coefficients were determined by a least-squares fitting method. The specific volumes of solid and liquid amorphous polymers determined by the empirical eq, agree with the measured values to within 1.07% to 1.80% except for PPO. The volume strain Kv of the solid and molten polymer alloys changed irregularly depending on the mixing ratio. It is minimum when the mixing ratio is PPO/PS= 20/80 weight percent.
Key words: p-ƒË-T properties / Equation of state / Isothermal testing method / Polymer alloy / Volume strain