Characterization of semi‐interpenetrating polymer network polystyrene cation‐exchange membranes

Abstract

Polystyrene cation exchange membranes were prepared by a PVC-based semi-interpenetrating polymer network (IPN) method. The reaction behaviors during polymerization and sulfonation in the preparation method were investigated. The prepared membranes were characterized in terms of the physical and electrochemical properties. The membranes exhibited reasonable mechanical properties (tensile strength, 13 MPa, and elongation at break, 52%) for an ion-exchange membrane with the ratio of polystyrene-divinylbenzene (DVB)/poly(vinyl chloride) (PVC) (R St-DVB/PVC ) of below 0.9. Fourier transform infrared/attenuated total reflectance, differential scanning calorimetry, and scanning electron microscopy studies revealed the formation of a homogeneous membrane. The resulting membrane showed membrane electrical resistance of 2.0 ⍀ cm 2 and ion-exchange capacity of 3.0 meq/g dry membrane. The current-voltage (I-V) curves of the membrane show that the semi-IPN polystyrene membranes can be properly used at a high current density, and that the distribution of cationexchange sites in the membrane was more homogenous than that in commercial membranes.

Anion exchange membranes based on semi-interpenetrating polymer network of quaternized chitosan and polystyrene

“…The two absorption peaks at 1660 and 1590 cm À1 for commercial chitosan are assigned to the C@O stretch of the secondary amide and the N-H bending of the primary amine, respectively [35]. The C-H bending of trimethylammonium group is registered at 1480 cm À1 for semi-IPN-0 confirming the existence of the quaternary ammonium salt in the QCS [27], and this absorption is shielded by the stretching vibration of the skeletal aromatic rings of the PS in the spectra of semi-IPN-8 and semi-IPN-21 [28]. It is also observed that the peak corresponding to the primary amine (1590 cm À1 ) of chitosan dwindles and a new peak at around 1640 cm À1 for semi-IPN-X (X -0) membranes was recorded, indicating the change of the primary amine to the secondary amine structure due to the reactions at NH 2 sites on the chitosan chains [23].…”

“…It is also observed that the peak corresponding to the primary amine (1590 cm À1 ) of chitosan dwindles and a new peak at around 1640 cm À1 for semi-IPN-X (X -0) membranes was recorded, indicating the change of the primary amine to the secondary amine structure due to the reactions at NH 2 sites on the chitosan chains [23]. The peaks at 3025, 1600, 1500, and 1493 cm À1 in the spectra of the semi-IPN-8 and semi-IPN-21 are attributed to the stretching vibration of the skeletal aromatic ring of the PS [28]. These results demonstrate that quaternary amino groups have been effectively grafted onto the chitosan backbones to form the QCS, and the linear PS has been synthesized to form the semi-IPN system with the cross-linked QCS together.…”

“…Attempts have also been made to develop AEMs by the preparation of chitosan composite membranes with other polymers [19]. With the aim of enhancement of the mechanical strength of the polymer membranes, a technology has been developed to fabricate composite membranes with a structure of so-called semi-interpenetrating polymer network (semi-IPN) [28][29][30][31]. The semi-IPN comprises at least one of the networks, in which one or more linear and branched polymers penetrated on a molecular scale of the macromolecules.…”

“…This technique has been used to improve the mechanical properties of the proton-conducting polymer membranes such as Nafion [32], sulfonated poly (ether ether ketone) [30], and poly (styrenesulfonic) acid membranes [33]. However, the AEMs based on the concept of semi-IPN are seldom to be reported [28,29].…”

Preparation and characterization of a cation exchange membrane using a styrene-hydroxyethyl acrylate-lauryl methacrylate terpolymer

“…8,9 The available substrate materials for preparing ion-exchange membranes are poly(ether ether ketone), poly(phosphazene), polystyrene, polyimide, poly(ether sulfone) (PES), polysulfone and so on. [10][11][12][13][14][15][16] It is generally agreed that cation exchange membranes should have high chemical and mechanical stability with favorable electrochemical properties.…”