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090			_aB-16341
245	1	0	_aOn the mechanism of gas transport in rigid polymer membranes
490	0		_vJournal of Applied Polymer Science, 49(12), p.2081-2090, 1993
520	3		_aConventional polymers are compared as gas separation membrane materials with "tailormade" polymers. The increased permeability of the latter are due to their higher free volume available for gas transport. The increased free volume is associated with the rigidity polymer backbone. Free volume is obtained by subtracting the occupied volume, calculated using group contributions from the polymer specific volume. Wide Angle X-ray techniques are used to obtain average d-spacings that are interpreted in terms of average intermolecular space, and that are related to permeability data. These highly permeable rigid polymer membranes have high glass transition temperatures. The physical parameters, that is, Tg and the jump in heat capacity (?Cp), are obtained with Differential Scanning Calorimetry, and are used to obtain an estimation of free volume. A good correlation for a series of random copoly[p, m-phenylene(4-phenyl)-1,2,4-triazoles]is obtained. A relationship between permeability and a free volume term, which can be estimated from thermodynamic properties, is equally valid for a wide variety of conventional polymers.
650	1	4	_aCALORIMETRY
650	1	4	_aCOPOLYMERS
650	1	4	_aCORRELATION METHODS
650	1	4	_aGASES
650	1	4	_aGLASS TRANSITION
650	1	4	_aMATHEMATICAL MODELS
650	1	4	_aMECHANICAL PERMEABILITY
650	1	4	_aMOLECULAR STRUCTURE
650	1	4	_aSPECIFIC HEAT
650	1	4	_aTHERMAL EFFECTS
650	1	4	_aTRANSPORT PROPERTIES
650	1	4	_aX RAY ANALYSIS
700	1	2	_aHensema, E.R.
700	1	2	_aMulder, M.H.V.
700	1	2	_aSmolders, C.A.
856	4	0	_uhttps://drive.google.com/file/d/1jrEUStPTkOIV586Qt1XDjrhyLpIL_xaD/view?usp=drivesdk _zPara ver el documento ingresa a Google con tu cuenta: @cicy.edu.mx
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