IUPAC-NIST Solubilities Database

IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Solubility System: Carbon dioxide with Polyimide Upilex R

Components:
   (1) Carbon dioxide; CO2; [124-38-9]  NIST Chemistry WebBook for detail
   (2) Polyimide Upilex R; ; [26615-45-2]  NIST Chemistry WebBook for detail

Evaluator:
   Yu. P. Yampol-skii, A. V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, April, 1994

Critical Evaluation:

        Three investigations are available on sorption of CO₂ in the polyimide obtained from 3.3', 4,4'-biphenyltetracarboxydianhydride and 4.4'-oxydianiline known under the tradename Upilex R.^1-3 The authors studied commercial samples of Upilex R, but in one case specimens synthesized and pretreated under different conditions were investigated as well.³ For the temperature range 308—383 K and at pressures up to 3 MPa, the sorption isotherms can be described by parameters shown in the table which are based on data reported in two papers^1,3 by the same group. The results of Sada et al.² are somewhat different, particularly at lower temperatures.
Figures 82 , 83, and 84 show the temperature dependences of S,b, and k_D, respectfully.
      A least squares treatment of the temperature dependence of k_D, b, and S resulted in the following values of enthalpies: ΔH_D = —11.10 kJ/mol
ΔH_H = —13.13 J/mol
ΔH_S = —27.35 kJ/mol.
     The temperature dependence of Langmuir capacity adsorption parameter C'_H shows that it vanishes in the vicinity of 450 K or at temperatures much lower than the glass transition tensperatsre of this polymer. The dual mode sorption parameters can be found based on fugacity instead of pressure.² The values calculated in two cases do not differ greater than by 10 %, although the enthalpies ΔH_D and ΔH_H are greater when the parameters are found via fugacity.
     A study of the effects of pretreatment of the films indicated³ that the presence of the solvent led to the increase in the apparent solubility coefficient, while the annealing resulted in the opposite effect.

Experimental Data: (Notes on the Nomenclature)

Selected dual mode sorption parameters for the system Upilex R-CO₂
T/K	Henry's law constant, K	Langmuir's parameter, C_H	Affinity Coefficient b	Keunen coefficient, S [S = k_D + C'_Hb]	Reference
308	0.596	12.0	0.478	6.3	3
323	0.50	8.6	0.44	4.3	1
323	0.456	10.3	0.348	4.0	3
353	0.335	5.9	0.252	1.8	3
353	0.35	5.0	0.30	1.8	1
383	0.254	3.4	0.162	0.8	3
383	0.25	3.0	0.19	0.8	1

View Figure 1 for this Evaluation

View Figure 2 for this Evaluation

View Figure 3 for this Evaluation

Notes:
^*  Units: k_D and S/cm^-3 atm^-1; C'_H/cm³(STP) cm^-3; b/atm^-1.

References: (Click a link to see its experimental data associated with the reference)

   1  K. Tanaka, H. Kita and K. Okamoto, Japan - US Polymer Symposium, p.249-250 (1985).
   2  E. Sada, H. Kumazawa and P. Xu, J. Appl. Polym. Sci. 35, 1497 (1988).
   3  K. Okamoto, K. Tanaka, H. Kita, A. Nakamura and Y, Kusuki, J. Polym. Sci., Part B: Polym. Phys. 27, 1221 (1989).