Graft copolymerization of vinyl monomers on modified cottons,XXI. Cu++/hydrazine hydrate redox system induced grafting of methyl methacrylate on periodate oxidized cellulose

Periodate oxidized cellulose was grafted with methyl methacrylate using hydrazine hydrate in presence and absence of Cu⁺⁺. The grafting reaction was favoured in presence of Cu⁺⁺ and it was advantageous to treat first the cellulose material with copper sulphate solution rather than to incorporate it in the polymerization system. The graft yields depended upon the concentrations of copper sulphate and hydrazine hydrate, pH, temperature, and time of polymerization as well as degree of oxidation of cellulose. There were optimal concentrations of copper sulphate (6–8 mmol/l) and hydrazine hydrate (2 mmol/l). A polymerization medium of pH 6 and a temperature of 60°C constituted to optimal pH and temperature for grafting. Oxidized cellulose proved to be more amenable to grafting as compared with unoxidized cellulose and the magnitude of grafting relied on the degree of oxidation. A tentative mechanism was also suggested for grafting of cellulose substrates with a vinyl monomer using a Cu⁺⁺-hydrazine hydrate redox system.     

The effect of cupric ion on the radiation grafting of N-vinyl-2-pyrrolidone and other hydrophilic monomers onto silicone rubber

Radiation grafting systems containing cupric ion, N-vinyl-2-pyrrolidone (N-VP) and other hydrophilic monomers were studied. Such systems, in certain Cu⁺⁺ion concentration ranges were found capable of producing extremely high levels of graft on silicone rubber and other polymers. Gellation of the homopolymer surrounding the grafted film was inhibited by the presence of cupric salts. An increase in the graft water content and decrease in the wettability of the grafted film surface was noted as the Cu⁺⁺ ion concentration in the grafting solution was increased. Based upon attenuated total reflectance infrared spectroscopic examination of the grafted materials, these effects could be explained by variations in the copolymer composition of the graft and increased penetration of the graft into the silicone rubber with increasing cupric ion concentration. The Cu⁺⁺/N-VP system allows many monomers which would ordinarily graft only with great difficulty to be readily grafted to polymeric surfaces. It also allows control over a number of graft parameters such as graft water content composition and penetration. Therefore, this system should be ideal for preparing a series of radiation grafted hydrogels to be used to evaluate important variables in the interactions of hydrophilic biomaterials and biological systems.     

A modified model and algorithm for flow‐enhanced crystallization—Application to fiber spinning

The graft copolymerization of acrylamide (AAm) monomer onto polyethylene‐coated polypropylene (PE‐co‐PP) nonwoven fabric was carried out by the mutual irradiation method. The general peculiarities of the grafting have been studied by gravimetric, scanning electron microscope (SEM), mechanical properties, and Fourier transform infrared (FTIR) methods. The influence of absorbed dose, dose rate, as well as the monomer concentration on the degree of grafting has been determined. Metal ions uptake of Cu²⁺, Co²⁺, Ni²⁺ by the grafted fabrics was evaluated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3240–3245, 2006     

Radiation‐induced grafting of styrene onto poly(tetrafluoroethylene) (PTFE) films. I. Effect of grafting conditions and properties of the grafted films

Radiation‐induced grafting of styrene onto poly(tetrafluoroethylene) (PTFE) films was studied by a simultaneous irradiation technique. Grafting was carried out using γ‐radiation from a ⁶⁰Co source at dose rates of 1.32–15.0 kGy h⁻¹ at room temperature. The effects of type of diluent, dose rate, irradiation dose, and the initial monomer concentration in the grafting solution on the degree of grafting were investigated. The degree of grafting was found to be strongly dependent upon the grafting conditions. The dependence of the initial rate of grafting on the dose rate and the initial monomer concentration in the grafting solution was found to be in the order of 0.6 and 1.7, respectively. The chemical structure and the crystallinity of the grafted PTFE films were studied by means of Fourier‐transform infrared, (FTIR), electron spectroscopy for chemical analysis (ESCA) and X‐ray diffractometry (XRD). © 2000 Society of Chemical Industry     

Radiation-induced grafting of N,N′-dimethylaminoethylmethacrylate onto chitosan films

Chitosan films were grafted with N,N ′-dimethylaminoethylmethacrylate using the ⁶⁰Co gamma irradiation method. The effect of solvent composition, monomer concentration, dose rate, and total dose on grafting was studied. The solvent composition has a marked effect on the degree of grafting. Maximum yield was obtained in the water-methanol (1 : 1) system. The percent grafting increased with monomer concentration and was found to be higher at a lower dose rate for a constant total dose of 0.216 Mrad. The tensile strength, crystallinity, and degree of swelling of grafted films decreased on increasing graft level. However, the graft copolymers showed improved thermal stability. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 869–877, 1997     

Preparation of hydrophilic membranes by grafting acrylic acid onto pre-irradiated teflon-FEP films

Grafting of acrylic acid onto pre-irradiated poly(tetrafluoroethylene-hexafluoropropylene) (Teflon-FEP) films was investigated, and the reaction parameters dose, dose rate, monomer concentration and grafting temperature were examined. The results show that the degree of grafting depends on the dose (5-60 kGy), the weight of grafted specimen increased up to 37%. The degree of grafting was found to be independent of the dose rate. The overall activation energies were calculated to be 28.8 and 81.6 kJ mol^-1 for treatments at above and below 50°C, respectively. The swelling of grafted films was measured in water, aqueous potassium hydroxide and methanol. The degree of swelling was found to increase with the length of grafted chains.     

Proton exchange membranes prepared by simultaneous radiation grafting of styrene onto poly(tetrafluoroethylene‐co‐hexafluoropropylene) films. I. Effect of grafting conditions

The simultaneous radiation grafting of styrene onto poly(tetrafluoroethylene‐co‐hexafluoropropylene) (FEP) films was studied at room temperature. The effects of grafting conditions (type of solvent, irradiation dose, dose rate, and monomer concentration) were investigated. The degree of grafting was found to be dependent on the investigated grafting conditions. The dependence of the initial rate of grafting on the dose rate and the monomer concentration was found to be of 0.5 and 1.3 orders, respectively. The results suggest that grafting proceeds by the so‐called front mechanism in which the grafting front starts at the surface of the film and moves internally toward the middle of the film by successive diffusion of styrene through the grafted layers. Some selected properties of the grafted films were evaluated in correlation with the degree of grafting. We found that the grafted FEP films possess good mechanical stability, which encourages their use for the preparation of proton exchange membranes. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 220–227, 2000     

Radiation-induced graft copolymerization of 2-hydroxyethyl methacrylate onto poly(γ-methyl-L-glutamate) membrane in ethanol solution

The radiation-induced graft copolymerization of 2-hydroxyethyl methacrylate (HEMA) onto poly(γ-methyl-L -glutamate) membranes was investigated in ethanol. The effects of dose, dose rate, concentration of HEMA, and temperature on the degree of grafting were studied. The initial rate of grafting copolymerization shows the following functional relationship equation: dG₀/dt = k[M]₀D˙^0.56. The average values of the apparent constants at 27 and 37°C for the initial rates of grafting are k₁ = 51 and k₂ = 91 G%h^−0.44 kGy^−0.56 mol⁻¹ L, respectively. The apparent activation energy of grafting copolymerization is E = 10.7 kcal/mol. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1575–1580, 1998     

Modification of natural rubber tubes for biomaterials. II. Radiation-induced grafting of N,N-dimethylaminoethylacrylate (DMAEA) onto natural rubber (NR) tubes

Radiation-induced simultaneous grafting of N,N-dimethylaminoethylacrylate (DMAEA) onto NR tubes has been studied to improve blood compatibility of NR tubes. In the grafting of DMAEA onto NR tubes, effect of grafting parameters such as solvent, monomer concentration, temperature, dose, and dose rate on the grafting yield was investigated. As the results, it was found that the grafting proceeds effectively in the presence of carbontetrachloride (CCI₄) as a solvent. The initial rate of grafting was found to be proportional to 0.70 power of dose rate and to 0.95 power of monomer concentration. The activation energy for this grafting system was calculated to be 6.78 kcal/mol. The evaluation of blood compatibility of NR-g-DMAEA was carried out by ex vivo test. Blood compatibility of those samples was found to be dependent on only grafting yield. When the degree of grafting is higher than 30 wt %, blood compatibility of NR tube could be improved by DMAEA grafting. This is the same tendency which that of previous grafting system of NR-g-DMAA.     

Development of amidoxime functionalized silica by radiation‐induced grafting

A novel amidoxime‐based silica adsorbent was prepared by using radiation‐induced grafting technique. Grafting of acrylonitrile (AN) on silanized silica that was silanized by vinyltriethoxysilane (VTES) was carried out in solvent‐free system. The grafting of AN was increased with increasing the absorbed dose and monomer concentration in the mixture. Grafting of 748% of AN was achieved at 20 kGy dose. The nitrile groups of acrylonitrile grafted silica (AN‐g‐S) were chemically converted into amidoxime groups. The structure of AN‐g‐S and its corresponding products was investigated by FTIR, SEM, TGA, BET, and XRD analysis. FTIR and EDX analysis confirmed the grafting of AN onto silica surface. The changed morphology of SEM images shows the presence polyacrylonitrile layers on silica particles. The adsorption application of amidoxime‐grafted silica (AO‐g‐S) was studied against Cu²⁺. Its adsorption capacity is strongly depended on the pH of the solution and 172 (mg/g) of Cu²⁺ uptake was obtained at pH 5.0. The developed adsorbent has potential application to remove heavy metal ions from aqueous solutions. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45437.     

Adsorption of Pb2+, Cu2+ and Co2+ by polypropylene fabric and polyethylene hollow fiber modified by radiation-induced graft copolymerization

Cation-exchange adsorbents were prepared by radiation-induced grafting of glycidyl methacrylate (GMA) onto polypropylene (PP) fabric and polyethylene (PE) hollow fiber and subsequent phosphonation of epoxy groups of poly(GMA) graft chains. The adsorption characteristics of Pb²⁺, Cu²⁺ and Co²⁺ for the two cation-exchange adsorbents were studied. In the grafting of GMA onto PP fabric, the degree of grafting (%) increased with an increase in reaction time, reaction temperature, and pre-irradiation dose. The maximum grafting yield was observed around 60% GMA concentration. In 50, 130 and 250% GMA-grafted PP fabric, the content of phosphoric acid was 1.52, 3.40 and 4.50 mmol/g at 80 °C in the 85 % phosphoric acid aqueous solution for 24 h, respectively. The adsorption of Pb²⁺, Cu²⁺ and Co²⁺ by PP fabric adsorbent was enhanced with an increased phosphoric acid content The order of adsorption capacity of the PP fabric adsorbent was Pb²⁺>Co²⁺>Cu²⁺. In adsorption of Pb²⁺, Cu²⁺ and Co²⁺ by PE hollow fiber, the amount of Pb²⁺ adsorbed by the PE hollow fiber adsorbent containing 1.21 mmol/g of -PO₃H wasca. 54.4 g per kg. The adsorption amount of Cu²⁺ and Co²⁺ in the same PE hollow fiber wasca. 21.0 g per kg andca. 32.1 g per kg, respectively. The order of adsorption of the PE hollow fiber adsorbent was Pb²⁺>Co²⁺>Cu²⁺.     

Pervaporation of ethanol—water mixture by Co60 γ-ray irradiation-modified nylon 4 membrane

The ethanol—water separation by pervaporation with γ-ray irradiation-modified nylon 4 membrane was investigated. The membrane was prepared by homografting γ-ray irradiation of vinyl acetate (VAc) monomer onto nylon 4, poly(vinyl acetate) (PVAc)-homo-g-nylon 4 followed by hydrolysis treatment, poly(vinyl alcohol) (PVA)-homo-g-nylon 4. The homografting method shows significant improvement in the degree of grafting of (VAc) onto nylon 4 over the heterografting method. For example, the degree of grafting of the VAc with 30 vol % and total dose of 2 Mrad for the heterografted method and for the homografted method are 14.1 and 42.2%, respectively. The effects of irradiation with or without oxygen in solution, irradiation time, VAc content, degree of grafting, crystallinity, feed concentration, and operating temperature on performances of the PVA-homo-g-nylon 4 membrane were carried out. Comparison of the separation factor of sorption in membrane (α_sorp) and that of pervaporation (α_perv) was made. A separation factor of 7.3 and a 0.691 kg/m² h permeation rate can be obtained by the PVA-homo-g-nylon 4 membrane with a degree of grafting of 42.2% for 90 wt % ethanol feed concentration. Compared with the unmodified nylon 4 membrane, which has the separation factor of 4 and permeation rate of 0.350 kg/m² h, the PVA-homo-g-nylon 4 membrane shows improved a separation factor and permeation rate. © 1993 John Wiley & Sons, Inc.     

Cation exchange membranes by radiation-induced graft copolymerization of styrene onto PFA copolymer films. I. Preparation and characterization of the graft copolymer

PFA-g-polystyrene graft copolymers were prepared by simultaneous radiation-induced graft copolymerization of styrene onto poly(tetrafluoroethylene-co-perfluorovinyl ether) (PFA) films. The effects of grafting conditions such as monomer concentration, dose, and dose rate were investigated. Three solvents, i.e., methanol, benzene, and dichloromethane, were used as diluents in this grafting system. Of the three solvents employed, dichloromethane was found to greatly enhance the grafting process, and the degree of grafting increased with the increase of monomer concentration until it reached its highest value at a styrene concentration of 60 (vol %). The dependence of the initial rate of grafting on the monomer concentration was found to be of the order of 1.2. The degree of grafting was found to increase with the increase in irradiation dose, while it considerably decreased with the increase in dose rate. The formation of graft copolymers was confirmed by FTIR analysis. The structural investigation by X-ray diffraction (XRD) shows that the degree of crystallinity content of such graft copolymers decreases with the increase in grafting, and consequently, the mechanical properties of the graft copolymers were influenced to some extent. Both tensile strength and elongation percent decreased with the increase in the degree of grafting. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2095–2102, 1999     

Synthesis and characterization of xanthan gum‐g‐N‐vinyl formamide with a potassium monopersulfate/Ag(I) system

A xanthan gum‐g‐N‐vinyl formamide graft copolymer was synthesized through the graft copolymerization of N‐vinyl formamide (NVF) onto xanthan gum with an efficient system, that is, potassium monopersulfate (PMS)/Ag(I) in an aqueous medium. The effects of the concentrations of Ag(I), PMS (KHSO₅), hydrogen ion, xanthan gum, and NVF along with the time and temperature on the graft copolymerization were studied by the determination of the grafting parameters (grafting ratio, add‐on, conversion, grafting efficiency, and homopolymer) and the rate of grafting. The maximum grafting ratio was obtained at a 0.6 g/dm³ concentration of xanthan gum. All the parameters showed an increasing trend with an increasing concentration of peroxymonosulfate, except the homopolymer percentage, which showed a decreasing trend. The grafting ratio, add‐on conversion, grafting efficiency, and rate of grafting increased with the concentration of Ag(I) increasing from 0.8 × 10^?2 to 1.2 × 10^?2 mol/dm³. The optimum time and temperature for the maximum degree of grafting were 90 min and 35°C, respectively. The graft copolymer was characterized with IR spectral analysis, thermogravimetric analysis, and differential calorimetry analysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1637–1645, 2006     

Preparation and characterization of a proton‐exchange membrane by the radiation grafting of styrene onto polytetrafluoroethylene films

Radiation‐induced simultaneous grafting of styrene onto polytetrafluoroethylene (PTFE) films and the subsequent sulfonation in the chlorosulfonic acid/dichloroethane were investigated. The effects of the main radiation grafting conditions, such as the type of solvents, irradiation dose, dose rate, the styrene concentrations, etc., on the degree of grafting (DOG) were studied. To elucidate the influence of both the grafting and sulfonation conditions on the properties of the PTFE‐g‐polystyrene‐sulfonic acid (PSSA) membranes, the sulfonation conditions, including the sulfonation temperature and the concentration of the ClSO₃H with respect to the DOG, were systematically evaluated. The grafted and sulfonated membranes were characterized by FTIR–ATR spectra, ion‐exchange capacity (IEC), water uptake, thickness measurement, etc. The as‐prepared PTFE‐g‐PSSA membranes in this work showed a good combination of a high IEC (0.85–2.75 meq g^?1), acceptable water uptake (8.86–56.9 wt %), low thickness, and volume expansion and/or contraction. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1415–1428, 2006     

Electron‐beam‐radiation‐induced grafting of acrylonitrile onto polypropylene fibers: Influence of the synthesis conditions

Electron‐beam‐radiation‐induced grafting of acrylonitrile onto polypropylene fibers was investigated with a pre‐irradiation method. Grafting conditions such as the solvents, additives, monomer concentration, radiation dose, and temperature were varied, and the effects on the degree of grafting were studied. The nature of the reaction medium and additives had a considerable influence on the degree of grafting. The dilution of acrylonitrile with N,N‐dimethylformamide significantly enhanced the degree of grafting in comparison with other solvents. The addition of sulfuric acid to the reaction mixture led to an increase in the degree of grafting and an acceleration of the rate of grafting. The order of dependence of the rate of grafting on the pre‐irradiation dose and monomer concentration was found to be 1.31 and 1.21, respectively, in the presence of sulfuric acid. The activation energy for grafting was calculated to be 21.9 kJ/mol. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis,characterization, and properties of polymeric flocculant with the function of trapping heavy metal ions

A novel crosslinked starch‐graft‐polyacrylamide‐co‐sodium xanthate (CSAX) was synthesized by grafting copolymerization reactions of crosslinked corn starch, acrylamide (AM), and sodium xanthate, using epichlorohydrin (EPI) as crosslinking reagent and ceric ammonium nitrate as initiator in aqueous solution. The effects of some factors, such as crosslinker, initiator, AM, NaOH and so forth, on the flocculation were investigated in terms of efficiency of grafting (% GE), grafting percentage (% GP), and viscosity averaged molecular weight (M) of the PAM pendant chains. The results showed that the CSAX was successfully synthesized with the different number and length of grafted PAM pendant chains and with the functions of removing both substance causing turbidity and heavy metal ions from aqueous solution. Under optimum synthesis conditions, CSAX exhibited excellent performances: the rate of turbidity removal (% T) reached 98.4% and the rate of Cu²⁺ removal (% R) reached 99.2% in water treatment, respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Modification of chitosan onto PE by irradiation in salt solutions and possible use as Cu2+ complex film for pest snail control

Chitosan‐grafted‐polyethylene (CS‐g‐PE) film was prepared using simultaneous radiation‐inducing grafting technique. The copper ion (Cu²⁺) adsorptivity on the CS‐g‐PE film was determined. The CS‐hydroxybenzyltriazole (CS‐HOBt), CS‐N‐hydroxysuccinimide (CS‐NHS), CS‐acetic acid (CS‐HOAc), and CS‐glutathione (CS‐GSH) were used as CS‐salts in aqueous solutions. Among these grafting solution systems, the CS‐g‐PE film prepared from CS‐HOBt solution showed the greatest grafting amount and highest Cu²⁺ adsorptivity, up to 30.2% (1.51 ppm, 7.56 µg cm^?2). The effects of the CS‐HOBt concentration and mixing solution on the grafting amount were also observed to clarify their efficacies to assist radiation‐induced grafting reaction. SEM/EDS mapping, ICP and XRF were used to clarify the Cu²⁺ adsorption capacity of the CS‐g‐PE film and the stability of Cu²⁺ on the CS‐g‐PE complex film. The Cu²⁺ showed its stability on the CS‐g‐PE film at room temperature in neutral and basic solutions. The Cu²⁺‐‐‐CS‐g‐PE complex film reduced pest snail breeding as high as 54%. The success of this observation is a new approach to modify PE surface with a functional biopolymer, CS containing Cu²⁺ complex for controlling pest snail breeding. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41204.     

Comparative study of the radiation‐induced grafting of styrene onto poly(tetrafluoroethylene‐co‐perfluoropropylvinyl ether) and polypropylene substrates. I: Kinetics and structural investigation

A comparative study has been made of the radiation grafting of styrene onto poly(tetrafluoroethylene‐co‐perfluoropropyl vinyl ether) (PFA) and polypropylene (PP) substrates, using the simultaneous irradiation method. Effects of grafting conditions such as monomer concentrations, type of solvent, dose rate and irradiation dose on the grafting yield were investigated. Under the same grafting conditions it was found that a higher degree of grafting of styrene was obtained using a mixture of dichloromethane/methanol solvents for PFA and methanol for PP and the degree of grafting was higher in PP than in PFA at all doses. However, the micro‐Raman spectroscopy analysis of the graft revealed that, for the same degree of grafting, the penetration depth of the grafted polystyrene into the substrate was higher in PFA than in PP substrates. In both polymers the crystallinity was hardly affected by the grafting process and the degree of crystallinity decreased slightly with grafting dose. The dependence of the initial rate of grafting on the dose rate and the monomer concentration was found to be 0.6 and 1.4 order for PFA and 0.15 and 2.2 for PP, respectively. The degree of grafting increased with increasing radiation dose in both polymers. However, the grafting yield decreased with an increase in the dose rate. The increase in the overall grafting yield for PFA and PP was accompanied by a proportional increase in the penetration depth of the graft into the substrates. Copyright © 2003 Society of Chemical Industry     

Performance studies of heterogeneous ion exchange membranes in the removal of bivalent metal ions in an electrodialysis stack

Heterogeneous anion and cation exchange membranes have been prepared by solution casting technique with poly(vinyl chloride) as inert binder and anion/cation exchange resins (?300 + 400 mesh) in a blend ratio of 60 : 40. The membranes were characterized with respect to their physical, mechanical, and electrochemical behavior. Anion and cation exchange membranes (10 cell pairs) were packed in an electrodialysis stack in a parallel plus series flow pattern. Desalting experiments were carried out with four different salt solutions, such as calcium chloride, magnesium chloride, cupric chloride, and nickel chloride (varying in their total dissolved solid from 500 to 1000 ppm), at different applied potentials and flow rates. The resultant current, percentage reduction in total dissolved solid, current efficiency, and energy consumption were calculated. The maximum current density in the electrodialysis stack was observed for calcium chloride solution and at any applied potential and flow rate the percentage reduction in total dissolved solid for Ca⁺⁺ > Cu⁺⁺ > Ni⁺⁺ > Mg⁺⁺. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009