Novel ion‐exchange resin beads with acid–base indicator property

Abstract

Copolymers of styrene and methyl acrylate were synthesized in the form of spherical beads (0.4 -1.2 mm) and sulfonated with concentrated sulfuric acid. The sulfonated copolymer shows an in-built acid-base indicator property; the yellow color in the acid medium changes to an intense pink color at the equivalence point. Also, the ion-exchange capacity of the sulfonated copolymer increases with time, reaches a maximum, and decreases thereafter. The results were explained in terms of Fourier transform infrared spectroscopic analysis considering internal Friedel-Craft acylation followed by cyclic dehydration leading to a conjugated structure. The developed ionexchange resin also demonstrated better performance in demineralization of water as compared with the conventional polystyrene-based beads. MaterialsSt (Fluka) and MA (Fluka) were purified by washing twice with aqueous NaOH solution (5% w/v) to

Sorption of Cr(VI) ions on two Lewatit-anion exchange resins and their quantitative determination using UV–visible spectrophotometer

“…Anion exchange resins are generally prepared from synthetic polymers such as styrene-divinylbenzene copolymers, which are aminated and methylated to form strongly base anion exchangers. Removal of Cr(VI) from cooling water and ground water by an ion exchanger has been investigated by some researchers [16,17]. Weak-base anion exchange resins are generally used for removing chromates from water at acidic pH values.…”

Fracture toughening of epoxy matrices with blends of resins of different molecular weights and other modifiers

“…A modifier‐rich phase segregated from the matrix through curing can allow the mechanism of crack propagation to be modified and consequently the fracture toughness of thermosetting matrices to be improved. A common method of improving the toughness of epoxy resins consists of introducing a liquid rubber as a second component,1 but this addition can lead to significant reductions in the thermal performance and mechanical strength of the thermosetting matrices 2–4…”

“…A common method of improving the toughness of epoxy resins consists of introducing a liquid rubber as a second component, 1 but this addition can lead to significant reductions in the thermal performance and mechanical strength of the thermosetting matrices. [2][3][4] Fortunately, another toughening technology can enhance fracture toughness without sacrificing the mechanical properties of the thermosetting systems. This technology uses high-modulus thermoplastics (TPs) with high glass-transition temperatures (T g 's).…”

Synthesis and Application of a Bi-Functional Sorbent Derived From Ethylacrylate-Divinylbenzene Copolymer for the Solid-Phase Extraction of Pesticides From Water

“…[11] The copolymer was converted into a bi-functional ion-exchanger carrying -COOH and -SO 3 H functional groups. This was achieved by employing a novel approach of hydrolyzing the ester groups with concentrated sulfuric acid [12] instead of using conventional alkaline hydrolysis. [13] The sulfuric acid hydrolyzed a significantly higher percentage of ester groups compared with alkaline hydrolysis, and it sulfonated the aromatic rings as well.…”