Optimum Graft Yield Research Articles

Modified Surface Polymer Prepared by using Radiation-Induced Grafting Co-polymerization Method and Its Application: A Mini Review

The use of radiation-induced grafting (RIG) polymerization techniques is an appealing way to create and develop polymerization of polymer. The method of copolymerization preparation was evaluated in this paper based on the types of radiation-induced grafting polymerization and their prospective applications. Based on the method of preparation, the optimum grafting yield of the monomer in the polymer backbone is described. The approach used to summarise this review was to go through polymer-related papers from the science direct online database from 2010 to 2021. Then, from those selected journals, the technique of preparation, the grafting yield, and the application were reviewed. Furthermore, the majority of researchers from reviewed journals employed gamma irradiation to prepare the modified polymer, followed by electron beam irradiation, plasma irradiation and UV irradiation. Gamma irradiation is popular because it has a better penetration rate and generates a purer result. As a result of this review paper, the radiation-induced graft polymer from the conducted study is ideal for use in biomedical applications, as a material for wastewater treatment fibre membranes, as an absorbent, and as a gas remover.

Modification of kenaf fibers by single step radiation functionalization of 2-hydroxyl methacrylate phosphoric acid (2-HMPA)

Phosphorylated adsorbent is commonly used in the extraction of rare earth metals and radioactive waste because of its high affinity in acidic condition. In this study, adsorbent containing phosphoric acid groups was synthesized by one-step radiation-induced grafting of 2-hydroxyl methacrylate phosphoric acid monomer (2-HMPA) onto kenaf fibers. The kenaf fibers were pre-treated with sodium chlorite prior grafting process. The incorporation of poly (2-HMPA) in the bleached kenaf fibers was confirmed by Fourier transform infrared spectroscopy (FTIR), FT-IR chemical imaging and scanning electron microscopy (SEM). The structural property was investigated using X-ray diffraction (XRD). The result revealed optimum grafting yield of 91.3% with 10% 2-HMPA and 50 kGy at 40 °C for 3 h. The performance of the synthesized adsorbent showed almost complete thorium adsorption. The removal efficiency of 99.9% thorium from aqueous solution was achieved using fibrous adsorbent at an initial thorium concentration of 10 mg/L, a reaction time of 3 h, and pH of 3 at room temperature. This single step combining grafting and functionalization to modify kenaf fibers showed sufficient property for application of natural fibers as adsorbent.

Grafting of Vinyl Pyrrolidone/Styrene onto Ethylene/Chlorotrifluoroethylene Membrane for Proton ExchangeMembrane Fuel Cell

Simultaneous gamma irradiation was proved to be an effective tool for ethylene/ chlorotrifluoroethylene grafting by styrene and vinyl pyrrolidone with different ratios. It was found that; the optimum grafting yield was 81% by using 40 kGy gamma irradiation dose when the binary monomers ratio was 1:1 (styrene: vinyl pyrrolidone). The grafted membranes were investigated for chemical structure by FT-IR and thermal properties by thermal gravimetric analysis. The mechanical properties were studied by measuring tensile strength while morphological structure was characterized by scanning electron microscope. The membranes’ free volume sizes were determined using positron annihilation lifetime spectroscopy (PALS). Ion exchange capacity, water uptake and membranes thickness were investigated and proton conductivity was evaluated. The optimum temperature for attaining the maximum fuel cell performance was at 75°C while it reduced by decreasing the temperature to 50°C or increasing it to 85°C. The fuel cell performance based highest yield of the grafted membrane was more durable than compressed Nr.118 (commercial membranes) up to 450hours.

Synthesis of Natural Cellulose–Based Graft Copolymers Using Methyl Methacrylate as an Efficient Monomer

AbstractCellulose‐based materials are one of the most significant candidates for the preparation of a number of copolymers by graft copolymerization owing to their linear structure, providing good reinforcing properties to the resulting copolymers. Therefore, in the present study, in an effort to develop novel low‐cost ecofriendly green polymeric materials, graft copolymers based on lignocellulose were synthesized by graft copolymerization of methyl methacrylate. Different reaction parameters were optimized to get the optimum graft yield, and the graft copolymers were subjected to the analysis of different physicochemical properties. © 2012 Wiley Periodicals, Inc. Adv Polym Techn 32: E741–E748, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21317

Functional Polymers from Lignocellulosic Materials: Synthesis, Characterization, and Evaluation of Properties

Functional polymers have been prepared through graft copolymerization of a binary monomer mixture of methyl methacrylate (MMA) and acrylamide (AAm) onto Agave americana fibers in the presence of Ce(IV) ions at a temperature of 45.0° ± 0.1°C. The different reaction parameters such as reaction time, temperature, and concentrations of initiator, nitric acid, and monomer were optimized for graft copolymerization of the principal monomer. The optimum graft yield and graft efficiency with MMA was found to be 43.50 and 11.54% respectively. The addition of acrylamide as comonomer showed a significant increase in graft copolymerization of methyl methacrylate onto the lignocellulosic fibers. A synergistic effect of acrylamide on methyl methacrylate was observed when graft copolymers were prepared using different feed compositions (f MMA) ranging from 0.3 to 0.9 at a constant feed molarity of 3.0 × 10−1 mol dm−3. The optimum graft yield of 53.30% was obtained when a feed molarity of 3.0 × 10−1 mol dm−3 was used at a feed composition of 0.7. The graft copolymers were characterized by various techniques such as FT-IR, TGA/DTA, X-RD, and SEM. Further graft copolymers were evaluated for physicochemical properties such as swelling behavior in different solvents, moisture absorption behavior, and resistance to chemicals as a function of percent grafting.

Synthesis and characterization of poly(hydroxamic acid)–poly(amidoxime) chelating ligands from polymer‐grafted acacia cellulose

AbstractGraft copolymerization of methyl acrylate (MA) and acrylonitrile (AN) onto acacia cellulose was carried out using free radical initiating process in which ceric ammonium nitrate (CAN) was used as an initiator. The optimum grafting yield was determined by the certain amount of acacia cellulose (AGU), mineral acid (H2SO4), CAN, MA, and AN at 0.062, 0.120, 0.016, 0.397, and 0.550 mol L−1, respectively. The poly(methyl acrylate‐co‐acrylonitrile)‐grafted acacia cellulose was obtained at 55°C after 2‐h stirring, and purified acrylic polymer‐grafted cellulose was characterized by FTIR and TG analysis. Therein, the ester and nitrile functional groups of the grafted copolymers were reacted with hydroxylamine solution for conversion into the hydroxamic acid and amidoxime ligands. The chelating behavior of the prepared ligands toward some metal ions was investigated using batch technique. The metal ions sorption capacities of the ligands were pH dependent, and the sorption capacity toward the metal ions was in the following order: Zn2+ > Fe3+ > Cr3+ > Cu2+ > Ni2+. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Thermo‐Responsive Gating Characteristics of Poly(N‐isopropylacrylamide)‐Grafted Membranes

AbstractBoth hydrophilic Nylon‐6 membranes and hydrophobic poly(vinylidene fluoride) (PVDF) membranes, with a wide range of grafting yields of poly(N‐isopropylacrylamide) (PNIPAM), were prepared using the plasma‐graft pore‐filling polymerization method. The effect of the physical and chemical properties of the substrates on the thermo‐responsive gating characteristics of the PNIPAM‐grafted membranes was investigated experimentally. For both the PVDF and Nylon‐6 membranes, the grafted PNIPAM polymers were found not only on the membranes outer surface, but also on the inner surfaces of the pores throughout the entire thickness of the membrane. The thermo‐responsive gating characteristics of the PNIPAM‐grafted membranes were heavily affected by the physical and chemical properties of the porous membrane substrates. The PNIPAM‐g‐Nylon‐6 membranes exhibited a much larger thermo‐responsive gating coefficient than the PNIPAM‐g‐PVDF membranes. Furthermore, to achieve the largest thermo‐responsive gating coefficient, the corresponding optimum grafting yield of PNIPAM for the PNIPAM‐g‐Nylon‐6 membranes was also larger than that for the PNIPAM‐g‐PVDF membranes.

Graft copolymerization of a mixture of perfluorooctyl-2 ethanol acrylic and stearyl methacrylate onto polyester fibers using benzoyl peroxide as initiator

Grafting polyester monofilaments with perfluorooctyl-2 ethanol acrylic monomer (C 8F 17–C 2H 4–O–CO–CHCH 2)/ stearyl methacrylate monomer (CH 3(CH 2) 17–O–CO–(CH 3)CCH 2) mixture was carried out with the aim of improving water and oil repellency and soil resistance. The percent grafting and the grafting rate depended upon the monomer concentration, the initiator concentration, and the time of reaction as well as the temperature of reaction. The optimum graft yield is obtained with a monomer concentration of 0.075 M and an initiator concentration of 1.8×10 −2. The effect of graft modification on the surface fibers has been investigated by crystallinity (thermal analysis) and surface topography (atomic force microscopy).

Reactive processing of polymers: Melt grafting of glycidyl methacrylate on ethylene propylene copolymer in the presence of a coagent

Glycidyl methacrylate (GMA) was grafted on ethylene-propylene copolymer during melt processing with peroxide initiation in the presence and absence of a more reactive comonomer (coagent), trimethylolpropane triacrylate (Tris). The characteristics of the grafting systems in terms of the grafting reaction yield and the nature and extent of the competing side reactions were examined. The homopolymers of GMA (Poly-GMA) and Tris (Poly-Tris) and the GMA-Tris copolymer (GMA-co-Tris) were synthesized and characterized. In the absence of the coagent, high levels of poly-GMA, which constituted the major competing reaction, was formed, giving rise to low GMA grafting levels. Further, this grafting system resulted in a high extent of gel formation and polymer crosslinking due to the high levels of peroxide needed to achieve optimum GMA grafting and a consequent large drop in the melt index (increased viscosity) of the polymer. In the presence of the coagent, however, the grafting system required much lower peroxide concentration, by almost an order of magnitude, to achieve the optimum grafting yield. The coagent-containing GMA-grafting system has also resulted in a drastic reduction in the extent of all competing reactions, and in particular, the GMA homopolymerization, leading to improved GMA grafting efficiency with no detectable gel or crosslinking. The mechanisms of the grafting reactions, in the presence and absence of Tris, are proposed.

Graft Copolymerization of Polyester Fibers with a Fluorine-Containing Monomer

Polyester monofilaments are grafted with perfluorooctyl-2 ethanol acrylic monomer (AC8) (C 8F17—C2H4—O—CO—CH=CH 2) to improve water and oil repellency and chemical and thermal stability and to enhance adhesion with a fluor matrix. Kinetic parameters like the percent grafting and grafting rate are measured as a function of monomer concentration, initiator concentration, and time and temperature of the re action. The results show that the optimum graft yield is obtained for a monomer con centration of 1.125 moles/liter and for an initiator concentration of 1.8 10-2 moles/ liter. The impact of the graft modification is characterized by crystallinity and surface topography.

Graft Copolymerization of Acrylamide on Swollen poly (Ethylene Terephthalate) Fibers Using Cerium Ammonium Nitrate Initiator

In this study the graft copolymerization of acrylamide (AAm) on swollen poly(ethylene terephthalate) (PET) fibers using cerium ammonium nitrate (CeAN) initiator was investigated. Five organic solvents, dimethylsulfoxide (DMSO), morpholine, acetic acid (HAc), n-butanol, and 1,2-dichloroethane (DCE), were used as swelling agents. DMSO was found to be the most suitable swelling agent. Solvent diffusion into the fibers was observed to increase with treatment time and temperature. The optimum graft yield was obtained when fibers were grafted after having been swollen in DMSO for a period of 1 hour at 140°C. Variation of graft yield with polymerization time and temperature, and monomer, initiator, and acid concentrations were investigated. Graft yields were observed to increase initially with polymerization time, then to level off, and were found to increase up to a certain monomer and Ce4+ concentration, then to decrease slightly. The effect of grafting on such fiber properties as diameter, viscosity, and moisture gain were also investigated.

Effect of Some Physical Treatments On the Reactivity of Cotton Stalk Pulp Toward Grafting

Abstract The effect of different physical treatments-for example, grinding, beating, and swelling with ethylene diamine-on the reactivity of bleached cotton stalk pulp toward grafting with methylmethacrylate monomer using ceric ion redox system is studied. the effect of monomer concentration and liquor ratio of grafting system on the graftability is also demonstrated. the graftability of treated samples is improved by using a liquor ratio of 50:1 instead of 40:1 for the untreated sample. Optimum graft yield for the beaten samples is obtained at 37°SR. Increasing the °SR of the beaten samples decreases the graft yield till it reaches a value lower than that of the untreated sample at 61°SR. Swelling of cotton stalk pulp with ethylene diamine has a high effect on the reactivity toward grafting. the physically treated pulps are characterized by infrared spectra to clarify the effect of these treatments on the crystallinity index (Cr I) of cotton stalk pulp.

A study of the graft copolymerization of methacrylic acid onto starch using the H2O2/Fe++ redox system

AbstractGraft copolymerization of methacrylic acid (MetAc) onto potato starch using H2O2/Fe++ redox system was investigated. The best conditions of the grafting reaction were determined and several variables were studied: initiator and monomer concentrations, time, and temperature. Percent grafting efficiency, percent grafting, percent grafted monomer conversion, and total conversion were obtained. The optimum graft yield was obtained at 7.3 × 10−3M H2O2 concentration and it was favored by increasing the methacrylic acid concentration and reaction time.