Fouling Prevention in Polymeric Membranes by Radiation Induced Graft Copolymerization

The application of membrane processes in various fields has now undergone accelerated developments, despite the presence of some hurdles impacting the process efficiency. Fouling is arguably the main hindrance for a wider implementation of polymeric membranes, particularly in pressure-driven membrane processes, causing higher costs of energy, operation, and maintenance. Radiation induced graft copolymerization (RIGC) is a powerful versatile technique for covalently imparting selected chemical functionalities to membrane surfaces, providing a potential solution to fouling problems. This article aims to systematically review the progress in modifications of polymeric membranes by RIGC of polar monomers onto membranes using various low- and high-energy radiation sources (UV, plasma, γ-rays, and electron beam) for fouling prevention. The feasibility of the modification method with respect to physico-chemical and antifouling properties of the membrane is discussed. Furthermore, the major challenges to the modified membranes in terms of sustainability are outlined and the future research directions are also highlighted. It is expected that this review would attract the attention of membrane developers, users, researchers, and scientists to appreciate the merits of using RIGC for modifying polymeric membranes to mitigate the fouling issue, increase membrane lifespan, and enhance the membrane system efficiency.

Synthesis and Characterization of Poly(methyl acrylate)-grafted-Sodium Salt of Partially Carboxymethylated Tamarind Kernel Powder

Ceric ammonium nitrate (CAN)-initiated graft copolymerization of methyl acrylate (MA) onto sodium salt of partially carboxymethylated tamarind kernel powder (Na-PCMTKP, DS = 0.15) was studied in an aqueous medium by solution polymerization technique. The growth of the graft reaction was monitored gravimetrically. The role of various synthesis variables on the grafting yields was examined to achieve the maximum graft yields (%G = 278.27, %GE = 94.38, %Hp = 5.62) and the influence of the synthesis variables in the graft copolymerization has been discussed. The reactivity of methyl acrylate (MA) towards graft copolymerization was compared with that of acrylonitrile (AN) on the basis of the results obtained from the earlier studies and plausible explanation was furnished for the observed reactivity of both the monomers towards grafting. The evaluated optimized reaction conditions were utilized to study the effect of reaction medium on grafting and it was found that reaction medium plays an important role in graft copolymerization. In order to ascertain the grafting, characterization of the samples made by FTIR, TGA and SEM was conducted. The synthesized novel graft copolymer may find potential application to be used as metal adsorbents.

Alginate Modification and Lectin-Conjugation Approach to Synthesize the Mucoadhesive Matrix

Alginates are natural anionic polyelectrolytes investigated in various biomedical applications, such as drug delivery, tissue engineering, and 3D bioprinting. Functionalization of alginates is one possible way to provide a broad range of requirements for those applications. A range of techniques, including esterification, amidation, acetylation, phosphorylation, sulfation, graft copolymerization, and oxidation and reduction, have been implemented for this purpose. The rationale behind these investigations is often the combination of such modified alginates with different molecules. Particularly promising are lectin conjugate macromolecules for lectin-mediated drug delivery, which enhance the bioavailability of active ingredients on a specific site. Most interesting for such application are alginate derivatives, because these macromolecules are more resistant to acidic and enzymatic degradation. This review will report recent progress in alginate modification and conjugation, focusing on alginate-lectin conjugation, which is proposed as a matrix for mucoadhesive drug delivery and provides a new perspective for future studies with these conjugation methods.

Graft Copolymerization of Methyl Methacrylate and Vinyltriethoxysilane onto Natural Rubber

Preparation and characterization of natural rubber grafted with methyl methacrylate (MMA) and vinytriethoxysilane (VTES) were performed in the present work. Graft copolymerization of methyl methacryate was carried out in latex stage, and VTES was added during the graft copolymerization of MMA. FTIR and NMR spectroscopy were used to investigate the structure of graft copolymer and determination of conversion and grafting efficiency of MMA. It confirmed that the poly(methyl methacrylate) (PMMA) and silica particles (PVTES) were successfully formed in NR-graft-PMMA-PVTES graft copolymer. Conversions of MMA were about 90-100%; however, MMA grafting efficiency decreased as the MMA concentrations increased. Tensile property of NR-graft-PMMA-PVTES was found to improve compared with that of pure NR.

Engineered Bioactive Polymeric Surfaces by Radiation Induced Graft Copolymerization: Strategies and Applications

The interest in developing antimicrobial surfaces is currently surging with the rise in global infectious disease events. Radiation-induced graft copolymerization (RIGC) is a powerful technique enabling permanent tunable and desired surface modifications imparting antimicrobial properties to polymer substrates to prevent disease transmission and provide safer biomaterials and healthcare products. This review aims to provide a broader perspective of the progress taking place in strategies for designing various antimicrobial polymeric surfaces using RIGC methods and their applications in medical devices, healthcare, textile, tissue engineering and food packing. Particularly, the use of UV, plasma, electron beam (EB) and γ-rays for biocides covalent immobilization to various polymers surfaces including nonwoven fabrics, films, nanofibers, nanocomposites, catheters, sutures, wound dressing patches and contact lenses is reviewed. The different strategies to enhance the grafted antimicrobial properties are discussed with an emphasis on the emerging approach of in-situ formation of metal nanoparticles (NPs) in radiation grafted substrates. The current applications of the polymers with antimicrobial surfaces are discussed together with their future research directions. It is expected that this review would attract attention of researchers and scientists to realize the merits of RIGC in developing timely, necessary antimicrobial materials to mitigate the fast-growing microbial activities and promote hygienic lifestyles.

Preparation of a Composite Material by Graft Copolymerization of Methylmethacrylate and Fish Gelatin Using a Photocatalyst - Complex Oxide RbTe1.5W0.5O6

A new composite material based on fish gelatin (FG) was obtained by graft copolymerization of methylmethacrylate (MMA) onto fish gelatin. The process was initiated by radicals formed by the RbTe1.5W0.5O6 photocatalyst under visible light (λ=400-700 nm) irradiation at room temperature. The characteristics of the new polymer material were obtained by the methods of elemental and physico-chemical analyses.