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Permeation and sorption of CO 2 through amine‐contained polyurethane and poly(urea–urethane) membranes
Author(s) -
Teo LiangSiong,
Kuo JenFeng,
Chen ChuhYung
Publication year - 1996
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/(sici)1097-4628(19960307)59:10<1627::aid-app15>3.0.co;2-t
Subject(s) - membrane , permeation , polymer , polymer chemistry , polyurethane , sorption , ethylene glycol , barrer , chemical engineering , materials science , solubility , peg ratio , synthetic membrane , chemistry , organic chemistry , adsorption , composite material , biochemistry , finance , engineering , economics
As an absorbent of CO 2 , tetraethylenepentamine (TEPA) and/or N ‐methyldiethanolamine (MDEA) was introduced into the hard segment as chain extenders of the series urethane polymer (PU), urea–urethane polymer (PUU), and segmented urethane/urea–urethane copolymer (SPU) based on 4,4′‐diphenylmethane diisocyanate (MDI) and either poly(ethylene glycol (PEG)‐400 or ‐600. The obtained polymers thus contained a nearly equal weight composition of both soft and hard segments and were prepared as polymer membranes for permeation and sorption of CO 2 . The properties of the polymer membranes were characterized using a Fourier transform IR spectrophotometer, thermal gravimetric analysis, and rheometric measurement. The permeation and sorption isotherms as a function of temperature and pressure as well as the activation energy of permeability and diffusivity and the enthalpy change of the solution were measured. The test temperatures were carried out above and below the T gs of soft‐segment domains or the T gh of hard‐segment domains. The steady‐state permeability ( P ) and diffusion coefficients ( D ) obtained ranged from 1.01 to 12.9 barrer and 1.04 to 4.04 cm 2 /s, respectively, and the solubility coefficients ( S ), from 0.529 to 3.43 cm 3 (STP)/cm 3 polymer‐atm at 10 atm and 35°C. The TEPA‐containing polymer membranes showed a smaller P and D but a larger S than did MDEA‐containing ones. The membranes comprising PEG‐600 exhibit the values of P , D , and S at about 11.5‐, 2.5‐, and 4.5‐fold the PEG‐400 ones, respectively. For SPU membranes, above T gs or T gs , the pressure dependencies of P followed the modified free‐volume model. On the other hand, below T gs , they exhibited a minimum permeability at a certain pressure caused by the plasticization action of sorbed CO 2 . The sorption isotherms of CO 2 indicated that the membranes comprising PEG‐400 can be described by a dual‐mode sorption model below T gs . Also, the SPU polymer membranes obied the Henry's law above T gs as well as T gh . The characteristic constants of the sorption model were also determined and are discussed. © 1996 John Wiley & Sons, Inc.