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Relations entre la structure et les proprietes des membranes de polytetrafluoroethylene greffe—III. Membranes non-ionisables contenant de la poly-n-vinylpyrrolidone
Authors:A.-M. Jendrychowska-Bonamour  J. Millequant
Affiliation:Laboratoire de Chimie Macromoléculaire sous Rayonnement, C.N.R.S., 94320 Thiais, France
Abstract:
Equilibrium properties (swelling) and transport phenomena (dialysis) of non-ionizable membranes, obtained by radiation grafting of N-vinylpyrrolidone onto thin PTFE films, were studied. Grafting was conducted by the direct method with monomer solutions in benzene. The overall activation energy of grafting determined between 20 and 50° is high (12.5 kcal mol?1): the reaction is controlled by the monomer diffusion into PTFE film. The length of grafted chains increases with temperature.The molality of the membranes decreases when the temperature of grafting increases; for a given grafting ratio, the swelling is higher for membranes containing a small number of long grafts than for membranes with numerous short branches. The transfer of both ions and water is a function of the free volume in the films, it depends on the grafting ratio and is not influenced by the preparation conditions.
Keywords:
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