The thermal study of pseudohomogeneous ion-exchange membranes

Abstract

Derivatograph was used to investigate pseudohomogeneous ion-exchange membranes. Two membrane types were examined: a) a membrane obtained from polyethylene film modified with the copolymer of styrene and DVB; and b) membrane AMF C-311 obtained on a film of fluorinated polymeric material.Although differential thermal analysis (DTA) has been used in the investigation of polymers only recently, a large number of papers concerning different problems in this field have already appeared. Only a few of these papers, however, have been devoted to cross-linked polyelectrolytes and more exclusively to ion-exchange resins [1-5], i.e. "homogeneous" polyelectrolytes. Up to date no publication dealing with "pseudohomogeneous" ion-exchange membranes has appeared. The pseudohomogeneous membrane is a system of two phases: a polymer film (polyethylene is most often used as matrix), with a cross-linked acid (e.g.polystyrenesulphonic acid) dispersed in the polymer film. The present investigation was undertaken to find the correlation between the thermal curves of a pseudohomogeneous cation-exchange membrane and the thermal properties of both phases of the membrane. ExperimentalTwo types of these membranes were examined: a) a membrane obtained from polyethylene film modified with the copolymer of styrene and DVB; this membrane was synthesized at Wroctaw Polytechnic School; b) membrane AMF C-311 (American Machine and Foundry Co.) obtained on a film of fluorinated polymeric material.The examination of other polymers was performed to explain endo-and exothermic effects occurring in the DTA curves of pseudohomogeneous ion-exchange membranes. These polymers were: the initial polyethylene film (PE); the polyethylene film modified with the copolymer of styrene and DVB (before sulphonation); the ethylene-styrene copolymer; the PE and PS homopolymer physical mixture; and the mixture of PE and polystyrenesulphonic acid ion-exchangers with different degrees of cross-linking.13"

Novel multiple methods and results in thermal analysis

“…Thermal analysis of some arylsulphanylamines containing benzene and naphthalene rings, resp., indicated that the compounds containing benzene rings have higher thermal stability [125]. Polish researchers report investigations of pseudo-homogeneous two-phase ion exchange membranes [126].…”