Recent Progress in Charged Polymer Chains Grafted by Radiation-Induced Graft Polymerization; Adsorption of Proteins and Immobilization of Inorganic Precipitates

Abstract

Radiation-induced graft polymerization provides industrially superior functionalization schemes by selection of existing polymer substrates and design of graft chains. In this review, by a pre-irradiation method of the radiation-induced graft polymerization and subsequent chemical modifications, charged polymer chains grafted onto various components and shapes of the polymer substrates are described. The charged graft chains immobilized onto a porous hollow-fiber membrane captured proteins in multilayers via multipoint binding. A membrane onto which positively charged graft chains are immobilized, i.e., an anion-exchange porous hollow-fiber membrane, was commercialized in 2011 for the removal of undesirable proteins in the purification of pharmaceuticals. On the other hand, a membrane onto which negatively charged graft chains are immobilized, i.e., a cation-exchange porous hollow-fiber membrane, exhibited a low permeation flux for pure water; however, the prepermeation of an aqueous solution of magnesium chloride through the membrane restored the permeation flux because of ionic crosslinking of graft chains with magnesium ions. The charged graft chains provide a precipitation field for inorganic compounds such as insoluble cobalt ferrocyanide. The graft chains entangle or penetrate a precipitate owing to electrostatic interactions with the surface charge on the precipitate. Braids and wound filters composed of insoluble-cobalt-ferrocyanide-impregnated fibers are used for the removal of radiocesium from contaminated water at Tokyo Electric Power Co. (TEPCO) Fukushima Daiichi Nuclear Power Plant.

Morphological characterization of grafted polymer electrolyte membranes at a surface layer for fuel cell application

“…Over the past 30 years, this technique has been extensively utilized to create the graft‐type polymer electrolyte membranes (PEMs) for fuel cell applications using graft monomers possessing sulfonic acid groups (i.e., conducting groups) grafted onto fully or partially fluorinated substrates or fully aromatic hydrocarbon substrates 2–4 . Furthermore, the recent advancements of radiation grafting are of interest to control composite architecture and graft polymerization to acquire the desired properties, such as drug loading and delivery, 5,6 active adsorbent, 7 separation, 8 and environmental protection 9 . In the pre‐irradiation grafting for preparation of PEMs, styrene monomer and its derivatives have been widely utilized to be grafted onto the irradiated polymer and subsequent sulfonation 2–4 .…”

Converting polyolefin fibres into CO2 adsorbent by radiation induced grafting

“…To develop SFA, specific ionic groups can be introduced to the surface of polymer substrates such as PE or PP fibres/nonwoven fabrics using graft copolymerization that can be initiated using thermal initiation, plasma treatment, redox initiation, photo-initiation in presence of UV and ionizing radiation [3,4]. Of all methods, initiation of graft copolymerization using ionizing radiation (known as radiation induced graft copolymerization or RIGC such as γ-rays and electron beam (EB), offers several advantages, including clean and environmentally friendly approach because eliminating the detrimental residues and providing precise and uniform control over the level of grafting and its homogeneity [5].…”

Torque Measurement as a Tool to Monitor the Breakdown of Cassava Starch Gels, by the Effect of Fenton's Initiator for Graft Copolymerization

“…Interesting papers in this respect were published by Reyes et al [8] and by Fanta and Doane [4]. And more recently, preactivation was also applied successfully by Ishihara et al for graft copolymerizations onto various polymer substrates [10]. After preinitiation of starch by irradiation, almost 100% selectivity for the graft reaction was reported, with acrylic acid in water.…”

“…After preinitiation of starch by irradiation, almost 100% selectivity for the graft reaction was reported, with acrylic acid in water. However, in the work of Reyes et al and Ishihara et al [8][9][10], the creation of radicals in starch was done by high energy radiation which is subject to severe drawbacks when industrial application is considered [9]. In several more recent articles, creation of radicals onto starch by chemical reaction before contacting the activated starch or cellulose to monomer was also reported [11][12][13][14][15].…”