Sulfonated gamma‐irradiated blend poly(styrene/ethylene‐vinyl acetate) membrane and their electrical properties

Abstract

A compatibilized blend membrane of polystyrene (PS)/polyethylene-vinyl acetate (PEVA) (50: 50) wt % was produced by compression molded at 180°C after irradiated by gamma ray at 50-kGy dose. The influence of gamma radiation on the properties of the blend (PS/PEVA) membrane was investigated. The irradiated samples showed an increase in the degree of crystallinity due to the presence of additional chemical bonds as observed by X-ray diffraction. As a result of irradiation, the miscibility of the two polymer matrix is enhanced by interfacial adhesion between the components in the blend polymer without any voids as observed by scanning electron microscopy. Furthermore, electrical conductivity in the blend (PS/PEVA) membrane was enhanced by introducing SO 3 H groups. Sulfonation process converts the blend from noncontact (5 × 10 −8 S cm −1 ) to semi-contact (3.8 × 10 −3 S cm −1 ) by AC current at wet condition, and this can find applications in the fuel cells. K E Y W O R D Scompatibilization, electrical conductivity, gamma irradiation, morphology, PS/EVA blends

pH stimuli‐responsive poly(acrylamide‐co‐sodium alginate) hydrogels prepared by γ‐radiation for improved compressive strength of concrete

“…The hydrogel samples are dried, weighed, and then immersed to swell in a solution of desired pH (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11), at 25°C for 24 h. The hydrogels are then withdrawn from the solution and weighed after removing excess surface water. The equilibrated swelling (ES) is measured twice using equation (1): where W t is the weight of swollen gel at certain time and W o is the weight of dried gel.…”

“…Hydrogels have a more open and porous channel structure at pH from 1 to 4 exhibiting a dense and smooth surface while the hydrogel showed a sponge-like porous architecture in alkaline media above pH 7 due to intramolecular H-bonding in PAMco-NaAlg networks. After a period of time (24 hr) which corresponds to the time required to obtain dried cement samples, the mold is removed (6). Also, it may be noticed that, by comparing between a micrograph of swollen hydrogel in acidic and basic media, the brightness is increased in accordance with the increase in pH bringing about an increase in charge densities.…”

“…The slurry is stirred well for 3 min and then poured in the aluminum mold (4 × 4 × 4) cm 3 (5). After a period of time (24 hr) which corresponds to the time required to obtain dried cement samples, the mold is removed (6).…”

“…pH-sensitive hydrogels are polyelectrolytes that contain weak acidic or weak basic groups in their network structure. [3][4][5][6] However, NaAlg tends to radiation degradation. [1] In the present study, polysaccharides with fully characterized sodium alginate (NaAlg) and radiation cross-linked hydrogel polyacrylamide (PAM) responsive to pH are obtained using free radical polymerization induced by gamma radiation.…”

“…Gamma irradiation is a promising method to prepare a wide polymeric material because of formation of active sites for initiating polymerizing throughout the matrix under appropriate experimental conditions. [3][4][5][6] However, NaAlg tends to radiation degradation. [7] Usually, for a given application, PAM is cross-linking with other polymeric materials.…”