Radiation-induced Grafting Of Acrylic Acid Research Articles

Modification of UHMWPE porous fibers by acrylic acid and its adsorption kinetics for Cu2+ removal

Polyacrylic acid-grafted ultrahigh molecular weight polyethylene (UHMWPE-g-PAA) fibers were prepared by radiation-induced grafting of acrylic acid onto UHMWPE porous fibers and were examined for Cu2+ removal from aqueous solutions. The developed fibers were characterized using Fourier transform infrared spectroscopy, mechanics test, scanning electron microscopy and energetic dispersive spectroscopy analysis. It was demonstrated that the UHMWPE fibers were modified successfully with grafted acrylic acid, which conferred excellent hydrophilic performance to UHMWPE porous fibers. The mechanics test indicated that considerable mechanical strength (~0.4 GPa) still reserved for the UHMWPE-g-PAA fibers in spite of somewhat radiation degradation. The high-strength, hydrophilic and porous natures render UHMWPE-g-PAA fibers promising as economical adsorbent in wastewater treatment. Prepared under different radiation dose and different degree of grafting of polyacrylic acid (PAA), the adsorption kinetics of the UHMWPE-g-PAA fibers was investigated using pseudo-first-order, pseudo-second-order and intraparticle diffusion models. The results reveal a large adsorption capacity of 63 mg g−1 for the UHMWPE-g-PAA fibers and the adsorption behavior follows perfectly a pseudo-second-order kinetics model regarding the Cu2+ solution adsorption.

Radiation-induced grafting of acrylic acid onto polypropylene film and its biodegradability

Abstract Polypropylene based commodity polyolefins are widely used in packaging, manufacturing, electrical, pharmaceutical and other applications. The aim of the present work is to study the effect of grafting of acrylic acid on the biodegradability of acrylic acid grafted polypropylene. The effect of different conditions showed that grafting percentage increased with increase in monomer concentration, radiation dose and inhibitor concentration but decreased with increase in radiation dose rate. The maximum grafting of 159.4% could be achieved at optimum conditions. The structure of grafted polypropylene films at different degree of grafting was characterized by EDS, FTIR, TGA, DSC, SEM and XRD. EDS studies showed that the increase in acrylic acid grafting percentage increased the hydrophilicity of the grafted films. FTIR studies indicated the presence of acrylic acid on the surface of polypropylene film. TGA studies revealed that thermal stability decreased with increase in grafting percentage. DSC studies showed that melting temperature and crystallinity of the grafted polypropylene films lower than polypropylene film. SEM studies indicated that increase in acrylic acid grafting percentage increased the wrinkles in the grafted films. The maximum biodegradability could be achieved to 6.85% for 90.5% grafting. This suggested that microorganisms present in the compost could biodegrade acrylic acid grafted polypropylene.

Radiation grafting of ionically crosslinked alginate/chitosan beads with acrylic acid for lead sorption

Radiation-induced grafting of acrylic acid onto alginate/chitosan beads was performed in solution at a dose rate of 20.6 Gy/min of Co-60 gamma rays. The effect of absorbed dose on grafting yield was investigated. The characterization of the grafted and un-grafted beads was performed by FTIR spectroscopy and the swelling measurements at different pHs was studied. It is found that as the pH value increases the swelling degree increases up to pH 6 but with further increase in pH value the swelling decreases. Also, it is noticed that the grafting yield increased with increase the irradiation dose. Both un-grafted and grafted alginate/chitosan beads were examined as sorbents for the removal of Pb ions from aqueous solutions. The sorption behavior of the sorbents was examined through pH, and equilibrium measurements. Grafted alginate/chitosan beads presented higher sorption capacity for Pb ions than un-grafted beads.

Radiation-induced grafting of acrylic acid onto expanded poly(tetrafluoroethylene) membranes

Expanded poly(tetrafluoroethylene) (ePTFE) is currently being applied in facial reconstruction surgery. One requirement for the use of ePTFE membranes in soft tissue replacements is establishment of a well-bonded interface with the surrounding bone. However, ePTFE is classified as bioinert, thus lacking in biomimetic properties which may result in poor osseointegration at the bone–implant interface. Thus, the introduction of functional groups onto the polymer surface was carried out in the current study using radiation induced grafting of acrylic acid (AA) yielding graft yields of up to 40%. This resulted in reducing the hydrophobicity (advancing contact angle reduced from 116 to 92°). XPS revealed that the grafted PAA was highly crosslinked. The effects of grafting conditions (dose, monomer concentration, as well as solvent) on the grafting outcome were evaluated. Grafting of tertbutyl acrylate (tBA) was investigated but low graft yields were obtained and this was shown to be unaffected by the solvent used during the grafting process. The mechanical properties of the AA grafted membranes were altered significantly and were dependent on the testing conditions (wet or dry).

Selectivity of Acrylic Acid Radiation Grafted Non-Woven Polypropylene Sheets towards Some Heavy Metals Ions

Graft polymerization has been considered as a general method for the modification of the physical and chemical properties of polymeric materials and of particular interest for synthesis of the hydrophilic membrane. In this study, hydrophilic carboxylic acid groups were introduced by radiation-induced grafting of acrylic acid (AAc) onto non-woven polypropylene fabric (NWPP). Different irradiation doses and (AAc) monomer concentrations were used to optimize grafting yield. Characterization and properties of the prepared graft copolymer were studied by employing X-ray Dif-fraction (XRD), Thermogravimetric Analysis (TGA), Scanning Electron Microscope (SEM ), Fourier Transform Infrared Spectrometry (FTIR) and differential scanning calorimeter (DSC). The prepared grafted materials were used for removing some heavy metals ions. The results showed that the non-woven PP grafted with (AAc) has good affinity toward Cu, Ni and Co.

Radiation synthesis of chitosan beads grafted with acrylic acid for metal ions sorption

Radiation-induced grafting of acrylic acid onto chitosan beads was performed in solution at a dose rate of 20.6 Gy/min of cobalt-60 gamma rays. The effect of absorbed dose on grafting yield was investigated. The characterization of the grafted material was performed by FTIR spectroscopy and the swelling measurements at different pHs. The grafting yield increased with the increase in dose, it reached 80% at 40 kGy irradiation dose. The removal of Pb and Cd ions from aqueous solutions was investigated with both ungrafted and grafted chitosan beads. The sorption behavior of the sorbents was examined through pH, kinetics and equilibrium measurements. Grafted chitosan beads presented higher sorption capacity for both metal ions than unmodified chitosan beads.

Optical dispersion of radiation-grafted fluoro-polymer

Controlling the index of refraction of polymers plays an important role in their advanced nonlinear optical and electro-optical applications as well as in nanophotonics and biophotonic technologies. A radiation-induced grafting of acrylic acid (AAc) onto poly(tetrafluoroethylene-co-perfluorovinyl ether) (PFA) copolymer films was carried out to synthesize graft copolymer films using gamma-irradiation by the mutual method. The resulted films were characterized by Fourier transform infrared spectroscopy. The grafting process is associated with cross-linking through which a considerable change in the material refractive index is achieved. The linear refractive index, optical dispersion, and the quantum parameters of grafted poly(tetrafluoroethylene-co-perfluorovinyl ether) (PFA-g-PAAc) polymeric film are determined in a wide spectral range of 0.2-3 microm. The wavelength for zero material dispersion is evaluated. The oscillator, dispersion, and lattice energies, respectively, are calculated revealing the optical properties of the studied trunk polymeric substrate and the grafted ones. The origin of the optical properties has been discussed.

The effect of additives on radiation-induced grafting of AA and SSS onto HDPE

A kind of ion-exchange membrane with strong acid and weak acid groups was prepared by radiation-induced grafting of acrylic acid (AA) and sodium styrene sulfonate (SSS) onto high-density polyethylene membrane (HDPE). The effect of additives such as sodium acetate, sodium chloride on grafting yield was studied. It was found that for either pre-irradiation method or simultaneous radiation method, the weak acid salt of strong alkali sodium acetate had a complex effect on the grafting yield by “pH effect” and “ion pair effect”, and the neutral salt sodium chloride was helpful to the increase of grafting yield by “ion pair effect”.

Electrochemical properties of polyolefin nonwoven fabric modified with carboxylic acid group for battery separator

Carboxylic acid group was introduced by radiation-induced grafting of acrylic acid (AAc) onto polyolefine nonwoven fabric (PNF), wherein the PNF comprises at least about 60% of a polyethylene having a melting temperature at ∼132°C and no more than about 40% of a second polypropylene having a lower melting temperature at ∼162°C, for a battery separator. The AAc-grafted PNF was characterized by XPS, SEM, DSC, TGA and porosimeter. The wetting speed, electrolyte retention, electrical resistance, and tensile strength were evaluated after grafting of AAc. It was found that the wetting speed, electrolyte retention, thickness, and ion-exchange capacity increased, whereas the electrical resistance decreased with increasing grafting yield. The tensile strength decreased with increasing grafting yield, whereas the elongation decreased with increasing grafting yield.

Radiation-induced graft polymerization of acrylic acid onto poly(tetrafluoroethylene-perfluorovinyl ether) copolymer films: complexation with some transition metals and biological activity

The radiation-induced grafting of acrylic acid onto poly(tetrafluoroethylene-perfluorovinyl ether) copolymer film was carried out to synthesize graft copolymer membranes of complexing ability with some selected transition metal ions such as Cr III, Mn II, Cu II, Ag I and Cd II. The complex formation of these graft copolymer–metal complexes was studied by atomic absorption spectroscopy, X-ray fluorescence, IR, UV and electron spin resonance spectrometry. The overall results suggest octahedral geometry for both Cr III and Mn II but square planar for Cu II. The results revealed the high stability of the obtained ligand–metal complexes. The biological activity of the grafted film and its complexes with various metal ions was investigated under the same conditions. Silver (I) complexed membrane had a strong biocidal effect for all tested bacteria. The biological activity for Cr III complex has been effected on E. coli and S. aureus, whereas the Cd II complex has its effect on E. coli, B. anthrax and B. cereus. The Cu II complex has only antifungal activity. No biological effect has appeared for both the grafted film or Mn II complexed one on either bacteria or fungi.

Electrochemical properties of polyethylene membrane modified with carboxylic acid group

Two cation-exchange membranes modified with the carboxylic acid group for battery separator were prepared by radiation-induced grafting of acrylic acid (AA) and methacrylic acid (MA) onto a polyethylene (PE) film. The surface area, thickness, volume, water uptake, ion-exchange capacity, specific electric resistance, and electrolyte flux were evaluated after PE film was grafted with AA and MA. It was found that KOH diffusion flux of AA-grafted PE membrane and MA-grafted PE membrane increased with an increase in the degree of grafting. AA-grafted PE membrane had a higher diffusion flux than MA-grafted PE membrane. Electrical resistance of two cation-exchange membranes modified with AA and MA decreased rapidly with an increase in the degree of grafting.

Characterization and application of radiation grafted membranes in waste treatment

Ionic membranes were prepared by radiation-induced grafting of acrylic acid onto low density polyethylene films. To elucidate the possibility of practical use, a study has been made for the characterization of the grafted and chemically treated membranes. The selectivity of such prepared membranes towards the chelation or complexation of different alkali metals was investigated, to find that the higher affinity is observed for K+, Na+ and Li+ ions compared to other alkali metals used. The metal uptake percent was determined using different techniques: flame photometer and X-ray fluorescence (XRF). The uptake of metal from its feed solution by the grafted membrane increased as the degree of grafting increased, i.e., it is directly proportional to the content of functional carboxylic acid groups in the graft copolymer. As a consequence, the electrical conductivity of metal feed solution decreased during such process of metal chelation by the membrane. The higher the grafting degree of membrane, the lower the electrical conductivity of metal feed solutions observed. The changes in thermal properties of the prepared membranes were investigated and characterized using differential scanning calorimeter (DSC), and thermal gravimetric analysis (TGA). The thermal stability of these membranes increased with a degree of grafting due to the formation of crosslinked network structure via hydrogen bonding. Furthermore, such stability is enhanced for the alkali-treated membranes even at high elevated temperatures. The prepared membranes showed a great promise for possible use in the recovery of uranium from zirconium in their wastes.

Introduction of carboxylic acid group to polypropylene fabric for battery separator

Carboxylic acid group was introduced by radiation-induced grafting of acrylic acid (AAc) onto a polypropylene (PP) nonwoven fabric for a battery separator. The AAc-grafted PP nonwoven fabric was characterized by IR, SEM, and TGA. The wetting speed, electrolyte retention, electrical resistance, and tensile strength were evaluated after grafting of AAc. It was found that the wetting speed, electrolyte retention, thickness, and ion-exchange capacity increased, whereas the electrical resistance decreased with increasing grafting yield. The elongation of AAc-grafted PP nonwoven fabric decreased with increasing grafting yield in dry state, whereas the elongation increased in wetting state.

Some investigations on radiation-grafting of acrylic acid onto poly(tetrafluoroethylene-ethylene) copolymer films and its complex with copper salt solution

A study was made of the graft copolymers obtained by radiation-induced grafting of acrylic acid onto poly(tetrafluoroethylene–ethylene) (ET) films. The conversion of the graft copolymers (60wt%) into metal acrylate copolymer complexes was carried out by treatment with various concentrations of aqueous CuCl2. These graft copolymer–metal complexes were studied by IR, UV spectrometry, X-ray diffraction (XDR), and electron spin resonance (ESR). The effect of temperature on the trunk, untreated grafted and treated grafted copolymer films was investigated by IR and thermogravimetric (TG) analysis. The influence of metal complexes of Cu2+ ions on the thermal properties and electrical conductivity was determined. It is assumed that such materials may be of great interest in the field of semiconducting materials, in addition to their resistance to degradation under high temperature, up to 300°C. © 1998 Society of Chemical Industry

Radiation-induced Grafting of Acrylic Acid and Vinyl Acetate Monomers onto Heavy-duty Poly(ethylene-vinyl acetate) Films

The preparation of graft films was carried out by direct radiation-induced graft polymerization of acrylic acid and vinyl acetate comonomer onto heavy-duty poly(ethylene–vinyl acetate) films. The effect of various comonomer compositions on the degree of grafting was investigated. The characterization and some selected properties of the graft copolymers prepared were studied. Thermal stability, mechanical and electrical properties of the films showed great promise for some practical applications. © of SCI.

Radiation‐grafting of acrylic acid onto ultrahigh molecular, high‐strength polyethylene fibers

AbstractRadiation‐induced grafting of acrylic acid onto ultrahigh molecular weight (UHMW) high‐strength polyethylene fibers to impart heat resistance and dyeability was undertaken. A preirradiation method was employed for grafting in an aqueous solution of acrylic acid containing a small amount of Mohr's salt as inhibitor. The grafting rate for UHMW high‐strength polyethylene fibers is one‐tenth of that for high‐density polyethylene fibers currently in use, and one‐hundredth, for high‐density polyethylene film. It has become clear that the preirradiation dose should be as low as 1 Mrad to keep the high strength of the starting fibers. The starting UHMW high‐strength polyethylene fiber begins to shrink remarkably at around 145°C, showing a maximum shrinkage of 90%, and then breaks at 154°C. When a 24% acrylic acid graft is converted to calcium salt, the grafted fiber retains the fiber form even at 300°C and gives only a maximum shrinkage of 11%. The less than 1% acrylic acid graft UHMW high‐strength polyethylene fibers and their calcium salt can be dyed to a deep shade with cationic dyes, whereas the starting fibers cannot be dyed with usual dyes including the cationic dye. © 1993 John Wiley & Sons, Inc.

Synthesis of complexing copolymers by the radiation-induced grafting method

The radiation-induced grafting of acrylic acid with acrylamide onto polyethylene, PE, and poly(isobutylene oxide), PIBO, was carried out to synthesize graft copolymers of complexing ability with such metal ions as lanthanides and transition metals. The adsorption efficiency of Tb 3+ obtained at [metal]/[ligand] = 1/10 with PIBO grafted with acrylic acid (AAc), PIBO- g-AAc, markedly increased with the increase in number of graft chains while it slightly decreased with the increase in molecular weight of graft chains. The adsorption of Sm 3+ was suppressed by Cu 2+ when these metal ions coexisted in solution at pH>5. Introducing poly(acrylamide) PAAm in graft chains improved not only the hydrophilic property of the graft copolymer but also its adsorption ability of metal ions. Sm 3+ was preferentially adsorbed in the surface region while Cu 2+ was adsorbed well inside the graft copolymers. The application of the modified Bjerrum method to the complexation made it clear that the complex forms were Sm(carboxyl) 2 for PE- g-AAc/Sm 3+ system, Sm(carboxyl) 3 for PE- g-(AAc-co-AAm)/Sm 3+ system, and Cu(carboxyl) 2 for both PE- g-AAc and PE- g-(AAc-co-AAm)/Sm 3+ systems, respectively. The logarithm of overall formation constant, log β n, increased with the increase in the acid dissociation constant p K a of graft chains.

Radiation-induced grafting of acrylic acid onto polyester fiber

Greffage par les rayons γ sur des fibres de polyethylene terephtalate. Acceleration du greffage par le dichlorure d'ethylene (gonflant). Tres faible modification des proprietes mecaniques par greffage

Radiation-induced grafting of acrylic acid onto polyethylene filaments

Radiation-induced grafting of acrylic acid onto high density polyethylene (PE) filaments was carried out in order to raise softening temperature and impart flame retardance and hydrophilic properties. Mutual γ-irradiation method was employed for the grafting in a mixture of acrylic acid (AA), ethylene dichloride and water containing a small amount of ferrous ammonium sulfate. The rate of grafting was very low at room temperature. On the other hand, large percent grafts were obtained when the grafting was performed at an elevated temperature. Activation energy for the initial rate of grafting was found to be 17 kcal mol between 20 and 60°C and 10 kcal mol between 60 and 80°C. Original PE filament begins to shrink at 70°C, show maximum shrinkage of 50% at 130°C and then breaks off at 136°C. When a 34% AA graft is converted to metallic salt such as sodium and calcium, the graft filament retains its filament form even above 300°C and gives maximum shrinkage of 15%. Burning tests by a wire-netting basket method indicate that graft filaments and its metallic salts do not form melting drops upon burning and are self-extinguishing. Original PE filament shows no moisture absorption, however, that of AA-grafted PE increases with increasing graft percent. The sodium salt of 15% graft shows the same level of moisture regain as cotton. The AA-grafted PE filament and its metallic salts can be dyed with cationic dyes even at 1% graft. Tensile properties of PE filament is impaired neither by grafting nor by conversion to metallic salts.

Synthesis of an Ion Exchange Membrane by Radiation-Induced Grafting of Acrylic Acid onto Poly(tetrafluoroethylene)

Acrylic acid was grafted onto a 100-μm thick poly(tetrafluoroethylene) (PTFE) film by simultaneous irradiation method. The effect of the dose rate on the grafting and, the changes in the film thickness, water absorption, and electric resistance of the grafted film were investigated. The results suggested that the nongrafted layer remains in the middle part of the film at lower percent of grafting and then disappears as the grafting proceeds. Interference microscopy of the grafted film revealed that this grafting occurs by a gradual diffusion of the monomer through the successive grafted layers which swell in the reaction medium, i.e., the grafted front moves inward into film.