Synthesis and characterization of radiation grafted copolymer for removal of nonionic organic contaminants

Nonionic organic contaminants such as phenol, benzene, and toluene from contaminated wastewater on laboratory scale can be effectively sorbed by cellulosic wood pulp sheet incorporated with three polar functional groups. The synthesis was carried out by graft copolymerization reaction of N,N‐dimethylaminoethylmethacrylate with methacrylic acid onto wood pulp. The preparation conditions at which the grafting process proceeds homogeneously are determined. Characterization and some selected properties of the original and grafted wood pulp were evaluated using FTIR and scanning electron microscope, also, the removal of phenol, benzene, and toluene on laboratory scale was investigated by using gas chromatography. It was found that phenol shows the highest removal percent than that of benzene and toluene. The efficiency of removal of the nonionic contaminants is found to be 97%, which shows a great promise for its applicability in the removal of organic contaminates from wastewater. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3589–3595, 2006     

Modification of leather properties by grafting. I. Effect of monomer chain on the physico‐mechanical properties of grafted leather

Although leather has a number of desirable properties such as thermal stability and fire retardancey, in addition to high toughness, it has a few drawbacks such as weight, high water absorption, poor soil and rot resistance, and nonuniformity. If these defects are overcome, leather's usefulness would be further enhanced and its competitive position with respect to synthetics would increase. This study reports the physical and mechanical properties of buffalo leather after chemical graft copolymerization with ethyl acrylate, butyl acrylate, and 2‐ethyl hexyl acrylate using benzoyl peroxide as an initiator. The optimum conditions for grafting (e.g., monomer and initiator concentrations, temperature and time of grafting, and solvent leather ratio) were extensively investigated. The study achieved outstanding properties for buffalo leather in reduction of water uptake after grafting, especially on using 2‐ethyl hexyl acrylate and butyl acrylate monomers. FT‐IR and solid ¹³C‐NMR for leather before and after grafting confirmed the grafting process.© 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1478–1483, 2003     

Effects of cobalt and potassium doping on thermal stability and electrical properties of radiation grafted acrylic acid onto poly(tetrafluoroethylene ethylene) copolymer films

Grafted copolymer of poly(tetrafluoroethylene ethylene) (ET) with acrylic acid (AAc) was prepared by direct radiation method. The obtained films were modified by treating with small amounts of Co²⁺ and K⁺ ions (1.0 wt %). The effects of such treatment on the thermal stability and electrical conductivity of these films were studied. Cobalt treatment did not much affect the thermal degradation of the films. The results obtained revealed that k⁺ treatment enhanced the thermal degradation of ET‐g‐PAAc, which started 273 K lower than that observed in the case of the untreated and Co²⁺‐treated films. Potassium and cobalt treatment of the investigated films increased their electrical conductivity (σ) and decreased the activation energy ΔE_σ. The increase in σ values was, however, more pronounced in the case of K⁺‐treated film. These results were discussed in terms of the effective increase in the hydrophilicity of the films, especially those treated with potassium. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 867–871, 2005     

PIV investigations on particle velocity distribution in uniform swirling regime of fluidization

In this study, hydrodynamics of spherical particles in uniform swirling regime of a fluidized bed were investigated using MATLAB supported particle imaging velocimetry (PIV). A least investigated mesh-type distributor was used to fluidize the bed particles, at different air entry angles, for future applications in coating and granulation industry. A quarter of the bed was photographed using high speed imaging technique and the respective velocity fields of the swirling particles were produced using PIV technique. The Gaussian distribution of the particle velocity profiles was predicted at low superficial air velocity; particles near the border of the bed showed relatively low velocity than that swirled in the middle of the test section. However, at high superficial velocity, the particles near the central cone moved with velocity comparable to the particle velocity in the middle of the test section. Contrarily, the particles in the vicinity of the outer bed-wall maintained their steady state motion at all superficial air velocities. The average particle velocity experienced monotonic increase for more angular air intake. The magnitude of the particle velocity reduced by 6.35% for each \(3^{\circ }\) increment in the air entry angle.     

An experimental investigation on the effects of exponential window and impact force level on harmonic reduction in impact-synchronous modal analysis

A novel method called Impact-synchronous modal analysis (ISMA) was proposed previously which allows modal testing to be performed during operation. This technique focuses on signal processing of the upstream data to provide cleaner Frequency response function (FRF) estimation prior to modal extraction. Two important parameters, i.e., windowing function and impact force level were identified and their effect on the effectiveness of this technique were experimentally investigated. When performing modal testing during running condition, the cyclic loads signals are dominant in the measured response for the entire time history. Exponential window is effectively in minimizing leakage and attenuating signals of non-synchronous running speed, its harmonics and noises to zero at the end of each time record window block. Besides, with the information of the calculated cyclic force, suitable amount of impact force to be applied on the system could be decided prior to performing ISMA. Maximum allowable impact force could be determined from nonlinearity test using coherence function. By applying higher impact forces than the cyclic loads along with an ideal decay rate in ISMA, harmonic reduction is significantly achieved in FRF estimation. Subsequently, the dynamic characteristics of the system are successfully extracted from a cleaner FRF and the results obtained are comparable with Experimental modal analysis (EMA).     

Magnetic Properties of Zinc Ferrite Nanoparticles Synthesized by Coprecipitation Method

The influence of the precipitant and ferric concentration on the magnetic properties of coprecipitated zinc ferrite nanoparticles has been investigated. The nanoparticles were characterized using X-ray diffraction, scanning and transmission electron microscope, and vibrating sample magnetometer techniques. The results showed that the single-phase zinc ferrite with partially inverse spinel structures can be formed at high concentrations. The inversion coefficient calculated by the Rietveld method decreases with increasing of the concentrations, may be due to the crystal growth. The magnetic measurements exhibited that the coprecipitated zinc ferrite nanoparticles were superparamagnet and magnetization decreases with increasing of the concentrations through decreasing of inversion coefficient.     

Polyester condensation adducts as novel photo stabilizers for polystyrene

Polycondensation adducts formed by the reaction of maleic anhydride with some Polyalcohols, namely, phloroglucinol, glycerol, and ethylene glycol, were prepared, characterized, and investigated as photostabilizers for polystyrene. Their Photostabilizing effectiveness was evaluated by measuring the extent of weight loss (%), the amount of gel formed as well as the viscosity average molecular weight of the soluble fractions of the degraded polymer. The results indicated better stabilizing effects of these stabilizers compared with that of the UV absorber, phenyl salicylate. A synergistic effect was achieved when the investigated photostabilizers were mixed with phenyl salicylate in a weight ratio of 1 : 1, and a radical mechanism is proposed to account for the action of the polycondensation adducts as photostabilizers. J. VINYL ADDIT. TECHNOL., 19:293–301, 2013. © 2013 Society of Plastics Engineers     

Synthesis of glycidyl methacrylate containing diethanol amine and its binary copolymers with ethyl methacrylate and butyl methacrylate as nano‐size chelating resins for removal of heavy metal ions

One of the most important applications of chelating and functional polymers is their capability to recover metal ions from their solutions. This study concerns the synthesis of a hydrophilic glycidyl methacrylate (GMA) monomer‐bearing diethanol amine (DEA) chelating group from the reaction of GMA and DEA. The formed adduct (A) was characterized via FTIR and mass spectra and subjected to homopolymerization and binary copolymerization with ethyl methacrylate and butyl methacrylate. The copolymerization process was carried out via a semi‐batch emulsion polymerization technique by using potassium persulphate/sodium bisulphite as a redox pair initiation system and sodium dodecyl benzene sulphonate as an emulsifier at 65°C. The obtained polymers were characterized via FTIR, thermal gravimetric analysis, and UV–VIS. Volume‐average diameters (D_v) in nanoscale range for the prepared polymers were confirmed by transmission electron microscope investigation. It was shown that the obtained nano‐size chelating polymers have a powerful adsorption character toward transition metal ions (Cu⁺², Cr⁺³, Ni⁺², and Co⁺²) and efficient selectivity for Cu⁺² and Ni⁺² ions at normal pH. The effects of pH, time, and different comonomer feed compositions on the uptake of metal ions were studied. The reaction between the obtained chelating resins and different metal ions was confirmed to be a second‐order reaction. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of binary copolymers of methyl methacrylate with glycidyl methacrylate and 2‐hydroxy ethyl methacrylate as carriers for cellulase

Cellulase was immobilized directly on methyl methacrylate‐glycidyl methacrylate copolymer (MMA‐co‐GMA) and methyl methacrylate‐2‐hydroxy ethyl methacrylate copolymer (MMA‐co‐HEMA) by covalent attachment and crosslinking methods. The properties of the immobilized cellulase were investigated and compared with those of the free one. For the assays carried out through crosslinking method at 25°C and pH 7, the retained activities were found to be 91.92% and 74.63%, respectively, for MMA‐co‐GMA and MMA‐co‐HEMA crosslinked with 0.1% of 1‐cyclohexyl‐3‐(2‐morpholino‐ethyl) carbodiimide metho‐p‐toluenesulfonate (CMCT), respectively. The immobilized cellulase had better stability and higher retained activities with respect to pH, temperature, and storage stability than the free one. In the repeated use experiments, the immobilized cellulase using (MMA‐co‐GMA)‐CMCT (0.1%) and (MMA‐co‐HEMA)‐CMCT (0.1%) did not change after 10 and eight times of repeated use and maintained 67% and 62% from their original activities after 25 times, respectively. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010