Proton‐exchange membranes via the grafting of styrene and acrylic acid onto fluorinated ethylene propylene copolymer by a preirradiation technique. IV. Dynamic mechanical analysis, X‐ray diffraction, and scanning electron microscopy studies of grafted and sulfonated membranes

Abstract

ABSTRACT:The grafting of styrene and acrylic acid onto fluorinated ethylene propylene copolymer was carried out by a preirradiation technique. The resulting membranes were sulfonated with concentrated sulfuric acid. The effects of the degree of grafting and sulfonation on the structure of the membranes were studied by X-ray diffraction and scanning electron microscopy. The crystallinity percentage decreased with increasing grafting. Scanning electron microscopy studies confirmed that grafting took place by a front mechanism, by which grafting started at the surface and slowly proceeded inwards. The dynamic mechanical properties of the membranes and their sulfonated derivatives were also investigated. The storage modulus at room temperature increased with grafting and increased further with sulfonation.

Ionic polymer‐metal composites made from radiation grafted FEP‐g‐styrene‐SO3H membranes

“…The method of determination of IEC has been reported in our earlier studies. 17 The sulfonated membranes have been coated with silver by electrochemical deposition method. Resultant IPMCs have been characterized in terms of surface resistance, tensile properties, and actuation.…”

Analytical Evidence

“…The variation of crystallinity with the grafting percentage can also be illustrated as in Figure 4.25 [47] . The decrease in crystallinity upon the grafting of styrene and acrylic acid on fl uorinated ethylene propylene copolymer (FEP) and the post -grafting treatment (sulfonation) is due to the dilution effect of crystallites because of the incorporation of styrene -co -acrylic acid into the amorphous region of the FEP matrix as well as crystal disruption.…”

Aplicaciones de radiación gamma y UV para el injerto molecular y el diseño de matrices para aplicaciones terapéuticas

“…Las gráficas representativas de esta técnica se llaman difractogramas. Cuando se presentan máximos orientados se considera que el compuesto es cristalino y cuando no hay máximos, sino una zona ancha de dispersión el compuesto es amorfo [74][75][76][77]. Cuando se utiliza esta técnica con una platina de calentamiento controlado, es muy útil en la determinación de un cristal líquido polimérico.…”