Universiti Teknologi Malaysia Institutional Repository

Penetrant-induced plasticization in glassy polymer membranes for gas separation

Wong, Lorna and Ismail, Ahmad Fauzi (2000) Penetrant-induced plasticization in glassy polymer membranes for gas separation. In: Malaysian Science & Technology Congress (MSTC) 2000, 7-9 November 2000, Genting Highlands.



The present paper deals with the performance of glassy polymer membranes plasticized by penetrant gases. Penetrant induced plasticization of gas separation membranes has been the subject of a number of recent investigations. Historically, plasticization can be attributed to the swelling stresses exerted by the penetrant molecules on the polymer network. It appears that carbon dioxide behaves as a plasticizing agent for many glassy polymers by expandng the polymer lattice and increasing the frequency of molecular motions. In glassy polymers, the permeability to carbon dioxide is pressure dependent. Permeability can either increase or decrease with increasing feed pressure.It was thought that the permeability of most glassy polymers to gases decreases with increasing pressure in accordance with the predictions of the dual-sorption theory. Presumably, the plasticizing action of CO2 decreases the ability of the membrane to separate molecules thereby causing the reduction in selectivity. In gas separation membranes, plasticization effects are observed as anomalous sorption and permeation during measurements at elevated pressures. The alteration of a number of properties resulting from the polymer conditioning by the sorbed penetrant molecules was investigated. It has been demonstrated that high sorption of carbon dioxide results in a strong plasticizing effect on the properties of several polymers. Disentanglement of polymer chains at elevated pressure, the depression of the glass transition temperature by absorbed CO2 molecules, the decreasing of activation energy for diffusion with increasing concentration visualize the plasticization effect of carbon dioxide on glassy polymers.

Item Type:Conference or Workshop Item (Paper)
Uncontrolled Keywords:Carbon dioxide, gas separation, glassy polymer membrane, plasticization
Subjects:T Technology > T Technology (General)
Divisions:Chemical and Natural Resources Engineering (Formerly known)
ID Code:5260
Deposited By: Norhani Jusoh
Deposited On:13 Mar 2008 10:38
Last Modified:01 Jun 2010 15:28

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