Preparation and swelling properties of semi‐IPN hydrogels based on chitosan‐g‐poly(acrylic acid) and phosphorylated polyvinyl alcohol

The phosphorylated poly(vinyl alcohol) (P‐PVA) samples with various substitution degrees were prepared through the esterification reaction of PVA and phosphoric acid. By using chitosan (CTS), acrylic acid (AA) and P‐PVA as raw materials, ammonium persulphate (APS) as an initiator and N,N‐methylenebisacrylamide as a crosslinker, the CTS‐g‐PAA/P‐PVA semi‐interpenetrated polymer network (IPN) ssuperabsorbent hydrogel was prepared in aqueous solution by the graft copolymerization of CTS and AA and followed by an interpenetrating and crosslinking of P‐PVA chains. The hydrogel was characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC) techniques, and the influence of reaction variables, such as the substitution degree and content of P‐PVA on water absorbency were also investigated. FTIR and DSC results confirmed that PAA had been grafted onto CTS backbone and revealed the existence of phase separation and the formation of semi‐IPN network structure. SEM observations indicate that the incorporation of P‐PVA induced highly porous structure, and P‐PVA was uniformly dispersed in the polymeric network. Swelling results showed that CTS‐g‐PAA/P‐PVA semi‐IPN superabsorbent hydrogel exhibited improved swelling capability (421 g·g^?1 in distilled water and 55 g·g^?1 in 0.9 wt % NaCl solution) and swelling rate compared with CTS‐g‐PAA/PVA hydrogel (301 g·g^?1 in distilled water and 47 g·g^?1 in 0.9 wt % NaCl solution) due to the phosphorylation of PVA. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Sulfonated polyimide and poly (ethylene glycol) diacrylate based semi‐interpenetrating polymer network membranes for fuel cells

Semi‐interpenetrating polymer network (semi‐IPN) membranes based on novel sulfonated polyimide (SPI) and poly (ethylene glycol) diacrylate (PEGDA) have been prepared for the fuel cell applications. SPI was synthesized from 1,4,5,8‐naphthalenetetracarboxylic dianhydride, 4,4′‐diaminobiphenyl 2,2′‐disulfonic acid, and 2‐bis [4‐(4‐aminophenoxy) phenyl] hexafluoropropane. PEGDA was polymerized in the presence of SPI to synthesize semi‐IPN membranes of different ionic contents. These membranes were characterized by determining, ion exchange capacity, water uptake, water stability, proton conductivity, and thermal stability. The proton conductivity of the membranes increased with increasing PEGDA content in the order of 10^?1 S cm^?1 at 90°C. These interpenetrating network membranes showed higher water stability than the pure acid polyimide membrane. This study shows that semi‐IPN SPI membranes based on PEGDA which gives hydrophilic group and structural stability can be available candidates comparable to Nafion® 117 over 70°C. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

The swelling behaviors and network parameters of cationic starch‐g‐acrylic acid/poly(dimethyldiallylammonium chloride) semi‐interpenetrating polymer networks hydrogels

Amphiphilic semi‐interpenetrating polymer networks (semi‐IPN) hydrogels were prepared by a sequential‐IPN method by acrylic acid graft copolymerization into cationic starch in mild aqueous media of poly(dimethyldiallylammonium chloride). Some main factors were investigated to evaluate the swelling of hydrogels, and the network parameters M_c were given accordingly to elaborate the interaction between polymers. The chemical structure of the resulting hydrogel was confirmed using Fourier transform infrared spectroscopy. The cationic starch‐based semi‐IPN hydrogels achieved a high swelling capacity of 1070 g/g in deionized water and 94 g/g in 0.9 wt % NaCl solution, respectively) and high compressive stress in a high water content. Besides, a different pH‐dependent behavior was found for this semi‐IPN hydrogel. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation and properties of alkaline anion exchange membrane with semi‐interpenetrating polymer networks based on poly(vinylidene fluoride‐co‐hexafluoropropylene)

Alkaline anion exchange membrane with semi‐interpenetrating polymer network (s‐IPN) was constituted based upon quaternized poly(butyl acrylate‐co‐vinylbenzyl chloride) (QPBV) and poly(vinylidene fluoride‐co‐hexafluoropropylene) [P(VDF‐HFP)]. The QPBV was synthesized via the free radical copolymerization, followed by quaternization with N‐methylimidazole. The s‐IPN system was constituted by melting blend of QPBV and P(VDF‐HFP), and then crosslinking of P(VDF‐HFP). Ion exchange capacity, water uptake, mechanical performance, and thermal stability of these membranes were characterized. TEM showed that alkaline anion exchange membrane exhibited s‐IPN morphology with microphase separation. The fabricated s‐IPN membrane exhibited hydroxide ion conductivity up to 15 mS cm^?1 at 25 °C and a maximum DMFC power density of 46.55 mW cm^?2 at a load current density of 98 mA cm^?2 at 30 °C. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45775.     

Preparation and characterization of a semi‐interpenetrating network gel polymer electrolyte

Poly(PEG200 maleate) was synthesized as a new type crosslinkable prepolymer and the semi‐interpenetrating polymer network (semi‐IPN) gel electrolytes were prepared by means of thermal polymerization. Their intrinsic properties were characterized by FTIR spectroscopy, differential scanning calorimetry (DSC), X‐ray diffractions (XRD), scanning electron microscopy, alternating current impedance (AC impedance), and linear sweep voltammetry. The prepared polymer hosts are transparent and have good mechanical properties. The results of DSC and XRD confirm that the prepared hosts are in amorphous state and they can hold enough liquid electrolytes, which is favorable for Li⁺ ions to transport via both the absorbed liquid electrolyte and the gel of the entire systems. The semi‐IPN gel electrolytes exhibit high ionic conductivity on the order of 10^?3 S cm^?1. Their electrochemical stability up to +4.6 V against Li⁺/Li also makes them potential candidates for application as polymer electrolytes in devices. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Preparation of alginate/poly(N‐isopropylacrylamide) semi‐interpenetrating and fully interpenetrating polymer network hydrogels with γ‐ray irradiation and their swelling behaviors

Semi‐interpenetrating polymer network (semi‐IPN) and fully interpenetrating polymer network (full‐IPN) hydrogels composed of alginate and poly(N‐isopropylacrylamide) were prepared with γ‐ray irradiation. The semi‐IPN hydrogels were prepared through the irradiation of a mixed solution composed of alginate and N‐isopropylacrylamide (NIPAAm) monomer to simultaneously achieve the polymerization and self‐crosslinking of NIPAAm. The full‐IPN hydrogels were formed through the immersion of the semi‐IPN film in a calcium‐ion solution. The results for the swelling and deswelling behaviors showed that the swelling ratio of semi‐IPN hydrogels was higher than that of full‐IPN hydrogels. A semi‐IPN hydrogel containing more alginate exhibited relatively rapid swelling and deswelling rates, whereas a full‐IPN hydrogel showed an adverse tendency. All the hydrogels with NIPAAm exhibited a change in the swelling ratio around 30–40°C, and full‐IPN hydrogels showed more sensitive and reversible behavior than semi‐IPN hydrogels under a stepwise stimulus. In addition, the swelling ratio of the hydrogels continuously increased with the pH values, and the swelling processes were proven to be repeatable with pH changes. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4439–4446, 2006     

Feasibility of conducting semi‐interpenetrating networks based on a poly(ethylene oxide) network and poly(3,4‐ethylenedioxythiophene) in actuator design

A new type of synthetic pathway—the use of interpenetrating polymer networks (IPNs)—is proposed to design conducting polymer‐based actuators. Two types of materials with interesting conducting properties were prepared: (1) a semi‐IPN between poly(3,4‐ethylenedioxythiophene) (PEDOT) and branched poly(ethylene oxide) (PEO) network; (2) a tricomponent IPN between PEDOT and a PEO/polycarbonate (PC)–based network as the ionic conducting partner. In the first case, the influence of the amount of branching in the PEO network on the EDOT uptake and electrochemical properties was studied. A maximum conductivity (15 S cm^?1) was obtained for 60 wt % branched PEO in the material. Moreover, the dispersion profile of PEDOT in the material was shown by elemental analysis and energy dispersion spectroscopy to follow a gradient through the thickness of the film leading to a built‐in three‐layered device. With respect to PEO/PC materials, the best results were obtained for about 80 wt % PEO in the matrix where the material remains sufficiently elastomeric. In this case, the conductivity reaches about 1 S cm^?1 for a 10 to 30 wt % polycarbonate content. These materials are capable of reversible 45° angular deflections under a 0.5V potential difference. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3569–3577, 2003     

Regulation of micromorphology and proton conductivity of sulfonated polyimide/crosslinked PNIPAm semi‐interpenetrating networks by hydrogen bonding

A series of novel sulfonated polyimide (SPI)/crosslinked poly(N‐isopropylacrylamide) (cPNIPAm) semi‐interpenetrating polymer networks (semi‐IPNs) were synthesized as the proton exchange membranes for direct methanol fuel cells via in situ polymerization. The micromorphology and properties of the semi‐IPN membranes were characterized. The results indicated that the hydrogen bonds between cPNIPAm and SPI in the semi‐IPN structure were a crucial factor for regulating the micromorphology, proton conductivity and other properties of the semi‐IPN membranes. A more uniform sulfonic ionic cluster distribution was observed in the membrane of SPI‐20‐cPNIPAm with equimolar ratio of sulfonic acid groups and amido bonds, which could provide effective proton transport channels. The SPI‐20‐cPNIPAm exhibited a maximum proton conductivity of 0.331 S cm^?1 at 80 ^oC (relative humidity 100%), an optimal selectivity of 8.01 × 10⁵ S s cm^?3 and an improved fuel cell performance of 72 mW cm^?2 compared with both pristine SPI and other semi‐IPN membranes. The SPI‐20‐cPNIPAm semi‐IPN membranes also retained good mechanical properties and thermal stabilities on the whole. © 2014 Society of Chemical Industry     

Study of biomineralization of poly(vinyl alcohol)‐based scaffolds using an alternate soaking approach

The present work adds to the continuing efforts of designing a natural bone‐like structure by synthesizing a semi‐interpenetrating polymer network (IPN) of poly(vinyl alcohol)–poly[(acrylic acid)‐co‐acrylonitrile] and impregnating hydroxyapatite (HAP) into the polymer matrix by an alternate soaking process. The prepared HAP–polymer scaffolds were characterized using techniques like Fourier transform infrared spectroscopy, X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis and environmental scanning electron microscopy. The biomineralized semi‐IPN was evaluated for water sorption capacity and the data were utilized for calculating network parameters such as average molecular weight between crosslinks (M_c) and crosslink density (q). The impregnated HAP was quantified as a function of the chemical architecture of the semi‐IPN, number of reaction cycles and temperature of the swelling bath. Copyright © 2006 Society of Chemical Industry     

Swelling behavior of semi‐interpenetrating polymer network hydrogels composed of poly(vinyl alcohol) and poly(acrylamide‐co‐sodium methacrylate)

Interpenetrating polymer network (IPN) hydrogels based on poly(vinyl alcohol) (PVA) and poly(acrylamide‐co‐sodium methacrylate) poly(AAm‐co‐SMA) were prepared by the semi IPN method. These IPN hydrogels were prepared by polymerizing aqueous solution of acrylamide and sodium methacrylate, using ammonium persulphate/N,N,N¹,N¹‐tetramethylethylenediamine (APS/TMEDA) initiating system and N,N¹‐methylene‐bisacrylamide (MBA) as a crosslinker in the presence of a host polymer, poly(vinyl alcohol). The influence of reaction conditions, such as the concentration of PVA, sodium methacrylate, crosslinker, initiator, and reaction temperature, on the swelling behavior of these IPNs was investigated in detail. The results showed that the IPN hydrogels exhibited different swelling behavior as the reaction conditions varied. To verify the structural difference in the IPN hydrogels, scanning electron microscopy (SEM) was used to identify the morphological changes in the IPN as the concentration of crosslinker varied. In addition to MBA, two other crosslinkers were also employed in the preparation of IPNs to illustrate the difference in their swelling phenomena. The swelling kinetics, equilibrium water content, and water transport mechanism of all the IPN hydrogels were investigated. IPN hydrogels being ionic in nature, the swelling behavior was significantly affected by environmental conditions, such as temperature, ionic strength, and pH of the swelling medium. Further, their swelling behavior was also examined in different physiological bio‐fluids. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 302–314, 2005     

In situ preparation of polyaniline within neutral,anionic, and cationic superporous cryogel networks as conductive,semi‐interpenetrating polymer network cryogel composite systems

Polyaniline [p(An)], one of the most known conducting polymers, was prepared within superporus nonionic polyacrylamide [p(AAm)], anionic poly(2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid sodium salt) [p(AMPS)], and cationic poly(3‐acrylamidopropyltrimethyl ammonium chloride) [p(APTMACl)] cryogels. After they were synthesized, washed, and dried, the neutral p(AAm), anionic p(AMPS), and cationic p(APTMACl) cryogels were soaked in an ammonium persulfate/aniline solution (1:1.25 ratio) in 1 M hydrochloric acid for the in situ oxidative polymerization of p(An) with the cryogel matrices as templates or reactors. The prepared p(AAm)/p(An), p(AMPS)/p(An), and p(APTMACl)/p(An) semi‐interpenetrating polymer network (semi‐IPN) conductive cryogel composites were characterized with scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and conductivity analysis. The SEM images revealed that the superporus cryogel networks were almost completely filled with p(An) conductive polymers (CPs). Among the cryogel–CP semi‐IPNs, we found that p(AAm)/p(An) semi‐IPN conductive cryogel composites provided the highest conductivity values of 1.4 × 10^?2 ± 4 × 10^?4 S/cm; this was a 6.4 × 10⁶ fold increase in the conductivity from the values of 2.2 × 10^?9 ± 1 × 10^?10 for p(AAm) cryogels. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44137.     

Preparation and characterization of thermosensitive poly(N‐isopropylacrylamide)/poly(ethylene oxide) semi‐interpenetrating polymer networks

Temperature‐sensitive poly(N‐isopropylacrylamide) hydrogels were successfully synthesized by using poly(ethylene oxide) as the interpenetrating agent. The newly prepared semi‐interpenetrating polymer network (semi‐IPN) hydrogels exhibited much better properties as temperature‐sensitive polymers than they did in the past. Characterizations of the IPN hydrogels were investigated using a swelling experiment, FTIR spectroscopy, and differential scanning calorimetry (DSC). Semi‐IPN hydrogels exhibited a relatively high temperature dependent swelling ratio in the range of 23–28 at room temperature. DSC was used for the determination of the lower critical solution temperature of the semi‐IPN hydrogel. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3032–3036, 2003     

Preparation and properties of porous poly(sodium acrylate‐co‐acrylamide) salt‐resistant superabsorbent composite

A novel semi‐interpenetrating polymer networks (semi‐IPNs) porous salt‐resistant superabsorbent composite was prepared by copolymerization of partially neutralized acrylic acid and acrylamide using polyethylene glycol as semi‐IPNs composite, N,N′‐methylenebisacrylamide, triene propanol phosphate, and trihydroxymethyl propane glycidol ether as crosslinking agents, methanol, propanol, and butanol as foaming agents, and L ‐ascorbic acid and peroxide hydrogen as initiators. To improve the properties of swollen hydrogel, such as strength, resilience, permeabilities, and dispersion, the copolymer was surface‐crosslinked, and then blended with aluminum sulfate, sodium carbonate, and sodium 1‐octadecanol phosphate in the course of post treatment. The influences of reaction conditions on properties of superabsorbent composite were investigated and optimized, and the water absorbency of superabsorbent composite prepared at optimal conditions in 0.9 wt% NaCl aqueous solution under atmospheric pressure and certain load (P ≈ 2 × 10³ Pa) were 61 g g^?1 and 16.7 g g^?1, respectively. Moreover, the swelling rate reached 22.003 × 10^?3 g (g s)^?1. And the excellent hydrogel properties, such as hydrogel strength, resilience, permeabilities, and dispersion were also obtained. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

p(AAm/TA)‐based IPN hydrogel films with antimicrobial and antioxidant properties for biomedical applications

Interpenetrating polymer networks (IPN), either semi‐IPN (s‐IPN) or full IPN, based on a natural polymer tannic acid (TA) and synthetic poly(acrylamide) (p(AAm)) were prepared by incorporation of TA during p(AAm) hydrogel film preparation with and without crosslinking of TA simultaneously. The synthesis of p(AAm/TA) s‐IPN and IPN hydrogels with different amounts of TA were prepared by concurrent use of redox polymerization and epoxy crosslinking. The p(AAm)‐based hydrogels were completely degraded at 37.5°C within 9 and 2 days at pHs 7.4 and 9, respectively. Biocompatibility of p(AAm), s‐IPN, and IPN were tested with WST assay and double staining, they had 75% cell viability up to almost 20 μg mL^?1 concentration against L929 fibroblast cell. Antioxidant properties of IPN and s‐IPN hydrogels were investigated with FC and ABTS^? methods. Antimicrobial properties of TA‐containing s‐IPN, and IPN hydrogels were determined against three common bacterial strains, Escherichia coli ATCC 8739, Staphylococcus aureus ATCC 6538, and Bacillus subtilis ATCC 6633, and it was found that p(AAm/TA)‐based s‐IPN and IPN hydrogels are effective antimicrobial and antioxidant materials. Moreover, almost up to day‐long linear TA release profiles were obtained from IPN and s‐IPN hydrogels in phosphate buffer solution at pH 7.4 at 37.5°C. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41876.     

Preparation of PAA‐g‐PEG/PANI polymer gel electrolyte and its application in quasi solid state dye‐sensitized solar cells

A microporous hybrid polymer of poly(acrylic acid)‐g‐poly(ethylene glycol)/polyaniline (PAA‐g‐PEG/PANI) is synthesized by a two‐step solution polymerization method. The influence of aniline concentration on the conductivity of PAA‐g‐PEG/PANI gel electrolyte is discussed, when the concentration of aniline is 0.66 wt%, the conductivity of PAA‐g‐PEG/PANI gel electrolyte is 11.50 mS cm^?1. Using this gel electrolyte as host, a quasi solid state dye‐sensitized solar cell (QS‐DSSC) is assembled. The QS‐DSSC based on this gel electrolyte achieves a power conversion efficiency of 6.38% under a simulated solar illumination of 100 mW cm^?2 (AM 1.5). POLYM. ENG. SCI., 55:322–326, 2015. © 2014 Society of Plastics Engineers     

Blood protein adsorption onto a polymeric biomaterial of polyethylene glycol and poly[(2‐hydroxyethyl methacrylate)‐co‐acrylonitrile] and evaluation of in vitro blood compatibility

A semi‐interpenetrating polymer network (semi‐IPN) of polyethylene glycol (PEG) and crosslinked poly[(2‐hydroxyethyl methacrylate)‐co‐acrylonitrile] was prepared and adsorption of bovine serum albumin (BSA) on the IPN surfaces was investigated. The dynamic nature of the adsorption process was studied, and the effects of various experimental factors such as pH and ionic strength on the adsorption isotherms of BSA were investigated. Various kinetic parameters, such as the adsorption coefficient, rate constant for adsorption and penetration rate constants, were calculated. For assessment of in vitro blood compatibility of the IPN surfaces, water sorption, blood clot formation tests and percent hemolysis measurements were performed. Copyright © 2004 Society of Chemical Industry     

Solid‐state single‐ion conducting comb‐like siloxane copolymer electrolyte with improved conductivity and electrochemical window for lithium batteries

Achievement of high conductivity and electrochemical window at ambient temperature for an all‐solid polymer electrolyte used in lithium ion batteries is a challenge. Here, we report the synthesis and characterization of a novel solid‐state single‐ion electrolytes based on comb‐like siloxane copolymer with pendant lithium 4‐styrenesulfonyl (perfluorobutylsulfonyl) imide and poly(ethylene glycol). The highly delocalized anionic charges of ? SO₂? N^(–)? C₄F₉ have a weak association with lithium ions, resulting in the increase of mobile lithium ions number. The designed polymer electrolytes possess ultra‐low glass transition temperature in the range from ?73 to ?54 °C due to the special flexible polysiloxane. Promising electrochemical properties have been obtained, including a remarkably high conductivity of 3.7 × 10^?5 S/cm and electrochemical window of 5.2 V (vs. Li⁺/Li) at room temperature. A high lithium ion transference number of 0.80, and good compatibility with anode were also observed. These prominent characteristics endow the polymer electrolyte a potential for the application in high safety lithium ion batteries. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45848.     

Preparation and characteristic of a sodium alginate/carboxymethylated bacterial cellulose composite with a crosslinking semi‐interpenetrating network

A novel ionic crosslinking sodium alginate (SA)/carboxymethylated bacterial cellulose (CM‐BC) composite with a semi‐interpenetrating polymer network (semi‐IPN) structure was developed in this study. The composite was prepared through the blending of an SA gel with CM‐BC then crosslinking by Ca²⁺ followed by a freeze‐drying process. Scanning electron microscopy showed the composite matrix organized in a three‐dimensional network of CM‐BC interpenetrated against SA molecular chains with a quantity of calcium alginate microspheres upon the surface. The swelling ratios of the composite were enhanced by 183, 198, and 212% with the supplementation of CM‐BC weight fractions of 25, 50, and 75%, respectively; the swelling ratios changed with changing pH. The tensile modulus, tensile strength, and elongation at break of SA were enhanced by 165, 152, and 188%, respectively, with the addition of 50 wt % CM‐BC. This study demonstrated that the semi‐IPN structure dramatically changed the swelling and mechanical properties of the composite, and the semi‐IPN will be a promising candidate for biomedical applications such as wound dressings and skin tissue engineering. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39848.     

LiClO4 salt concentration effect on the properties of PVC‐modified low molecular weight LENR50‐based solid polymer electrolyte

A work was carried out on a solid polymeric electrolyte system comprising blends of poly (vinyl chloride) and liquid 50% epoxidized natural rubber (LENR50) as a polymer host with LiClO₄ as a salt and prepared by solution casting technique. In this paper, the main study was the effect of LiClO₄ salt concentration on the electrolyte properties. The effect of the salt on the electrolyte properties was characterized and analyzed with impedance spectroscopy (EIS), X‐ray diffraction (XRD), differential scanning calorimeter (DSC), and scanning electron microscopy (SEM). The EIS result showed that highest ionic conductivity was obtained at 30 wt % salt with a value of 2.3 × 10^?8 S cm^?1. The XRD results revealed that the LiClO₄ salt was fully complexed within the polymer host as no sharp peaks were observed. However, above 30 wt % of salt, some sharp peaks were observed. This phenomenon was caused by the association of ions. Meanwhile, DSC analysis showed that T_g increased as the salt content increased. This implied that LiClO₄ salt had interaction with polymer host by forming coordination bond. The morphologies' studies showed that good homogeneity and compatibility of the electrolyte were achieved. Upon the addition of the salt, formation of micropores occurred. It was noted that micropores which aid in mobility of ions in the electrolyte system has increased the ionic conductivity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

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

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 Ω cm² 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 cation‐exchange sites in the membrane was more homogenous than that in commercial membranes. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1488–1496, 2003