Papers by Keyword: Acrylamide

Abstract: Realizing the growing extraordinary interest in the development of polymer hydrogels, successful attempt has been made for synthesis of copolymer hydrogels from aqueous solution of acrylamide/bacterial cellulose (AAm/BC) with irradiation processing technology using Co-60 gamma source. The study envisaged to: (i) develop a novel high strength polymer nanocomposite hydrogels containing natural BC, and (ii) investigate chemical structure, morphology, and mechanical strength properties of the formed gels. The effectiveness of AAm/BC hydrogel for wound dressing application was also tested. Structure and properties of composite were investigated using Fourier Transform Infrared spectrophotometer (FTIR), Differential Scanning Calorimetry (DSC), and Atomic force microscopy (AFM). While investigating the influence of irradiation dose and concentration of acrylamide on gel content, swelling properties and thermal stability of copolymer hydrogel,maximum gel content of prepared hydrogel was obtained at the radiation dose of 40 kGy. Swelling ratio and equilibrium water content increased with increasing irradiation dose and concentration of acrylamide in feed solution. The water absorption of hydrogel increased with increased standing time in swelling medium. It was rapid up to 24 h and got slowed down thereafter. The water absorption also increased with increasing concentration of irradiation dose in the feed solution. The water absorption of copolymer hydrogel obtained at 40 kGy irradiation dose decreased from 1800 to 1400%. This type of diffusion of prepared hydrogel was found to be a non Fickian diffusion. The thermal stability of copolymer hydrogel prepared at the irradiation dose of 40 kGy increased with increasing amount of AAm in the feed solution. The mechanical behavior of composite hydrogels at optimum irradiation dose performed value of tensile and strain at 46.3MPa and 36.6%, respectively.

Abstract: pea starch and acrylamide were used as the raw materials, potassium peroxodisulfate and sodium sulfite were used as the initiator, EDTA (Ethylene Diamine Tetraacetic Acid) and urea were used as the auxiliaries to make starch grafting acrylamide polymer flocculating agent by the method of aqueous solution polymerization. The influence of reaction temperature, concentration of initiator and raw material ratio on the flocculating performance of products was analyzed by ternary quadratic orthogonal regression rotational combination experiment. The result shows that the flocculation effect will be the best when the reaction temperature is 60°C, the initiator is 5.00 ml, and the raw material ratio is 2.25.

Abstract: Amphoteric ionic polyacrylamide P (AM-DAC-AANa) was prepared in aqueous solution using acrylamide (AM), 2-(acryloyloxy) ethyltrimethylammonium chloride (DAC) and sodium acrylate (AANa) as materials by photo assisted initiation. The influences of reaction conditions on intrinsic viscosity and solubility of product were studied. Under the conditions of initiation temperature 20°C, monomer concentration 32%, pH=6 and initiator concentration 0.010%, the intrinsic viscosity and dissolving time of polymer were 13.56dL/g and 66min respectively. Moreover, the flocculating performance of the obtained copolymer was also studied. The results showed that under the conditions of P(AM-DAC-AANa) dosage 0.0250%, intrinsic viscosity 12.13dL·g^-1, ionic degree 25%, m (DAC):m (AANa)=1:2, the transmittance of the supernatant, flocculating rate and dewatering rate were 93.90%, 84.47% and 92.41% respectively.

Abstract: Superabsorbent polymer from waste polystyrene-graft-polyacrylamide was synthesized through emulsion polymerization technique using acrylamide as a monomer and potassium persulphate as an initiator in the presence of N,N-methylenebisacrylamide (NMBA) as a crosslinking agent. The effects of acrylamide loading was investigated to obtain the optimum condition that shows the best swelling capacity in three different aqueous medium; distilled water, saline solution and urea solution. Superabsorbent hydrogel were characterized by Fourier Transform Infrared (FTIR), thermogravimetric analysis (TGA) and electron scanning microscopy (SEM). Swelling test showed optimum absorbencies for distilled water, saline and urea solution were 1230 wt%, 1160 wt% and 440 wt% from their dry weight, respectively, recorded at ratio 1:10 of waste polystyrene to acrylamide. Meanwhile, the IR Spectroscopy proves that the grafting process between acrylamide and waste polystyrene was occurred in the hydrogel. Thermal degradation of the hydrogel started at 350 °C and the existence of porous unit can be observed in SEM micrographs.

Abstract: The production conditions have great influence on nutrition, color, flavor and evaluation of food safety of high temperature (180 °C ~ 190 °C) frying potato chips. The effects of potato slice thickness, total time of drying, frying time, the mixing of antioxidant and synergistic agent and additive on potato chips quality were studied according to the determination of water content, oil content, peroxide value, carbonyl value, acrylamide content and sensory score. The optimum process conditions are show as follows: the slice thickness is 1.0~1.5mm, the drying time is 45~55min, the frying time is 2.0min, the addition mass fraction of antioxidant BHT is 0.02%, the addition mass fraction of synergist citric acid is 0.05% and 0.3% CaCl₂ should be added to restrain produce of acrylamide.

Abstract: Reaction of acrylamide in inverse emulsion, adding Fe (EDTA)^2-, with ammonium persulfate (APS) to form complex initiation system, Fe (EDTA)^{2 -} is oxidized to Fe (EDTA)^-, the control effect of the Fe (EDTA)^- in the inverse emulsion polymerization of acrylamide was discussed. The results showed that acrylamide in inverse emulsion polymerization reaction by adding Fe (EDTA)^2-, When the complex concentration is 2.8×10^-4mol/L, n [(NH₄)₂S₂O₈]::n (FeSO₄):n (Na₂EDTA)=1:1:1.10, the reaction time was 6 hours, the amount of emulsifier is 3%,the reaction temperature is 40°C , The rate of conversion of monomer Increased in linear relationship with molecular weight, the final rate of conversion of monomer was 93.16%;a kinetic curve showed a good linear relationship, the coefficient of linear correlation was 0.997,Therefore, the Fe (EDTA) ^{2 -} have dual role firstly as a reducing agent of an oxidation - reduction initiator system and secondly as potential catalyst in reverse atom transfer radical polymerization (RATRP) .

Abstract: The inverse microemulsion copolymerization of poly (dimethyl diallyl ammonium chloride-acrylamide) (PDMDAAC-AM) has been studied using a blend of two surfactants Span-80 and OP-10 as the composite emulsifier in kerosene-water media. The effects of various polymerization parameters (e.g., polymerization method, reaction time, addition of electrolyte, oil-soluble initiator concentration and aqueous-to-oil phase volume ratio (A/O)) on the conversion and copolymer characteristics have been investigated. The optimum operating conditions for preparing (PDMDAAC-AM) were determined as reaction time 1h, HCOONa concentration 0.05% (w), AIBN concentration 0.045% (w), A/O 2/3 and semi-continuous process. Stable latex with high conversion (97.42%) and 267cm³/g intrinsic viscosity was obtained. In the semi-continuous process, the size distribution peak narrows along with the reaction process and the average diameter of the final product is 15.2 nm, which is significantly less than that prepared by one-time process.

Abstract: A super absorbent resin (SAR) of acrylic acid (AA)/acrylamide (AM) /organic montmorillonite (OMMT) composite was synthesized by aqueous solution polymerization. This process was carried out under precision microwave organic synthesis system and its single-mode focusing microwave irradiation technology was studied. The montmorillonite (MMT) was modified by treating with cetyltrimethylammonium bromide. Moreover, the factors that effect on liquid absorbency rate of the SAR were discussed, such as neutralization degree (ND) of AA, microwave irradiation time, microwave irradiation power and the dosage of the OMMT. It gave the best liquid absorbency rate (1520g.g^-1 and 165g.g^-1 in purified water and 0.9wt% NaCl solution, respectively).

Abstract: Sodium alginate (NaAlg) is considered to be a potential natural polymer for biomaterial applications, because of its hydrophilic properties that is capable to increase the swelling of hydrogels and biodegradable. This study describes the synthesis of a poly (acrylamide-co-acrylic acid) NaAlg superabsorbent hydrogels via crosslinking gamma radiation. The effect of irradiation dose (20-40 kGy) and NaAlg concentration (0.1-0.7 %) of on swelling of hydrogels were studied. The copolymers were characterized by Fourier transform infra red spectroscopy (FTIR) and scanning electron microscopy (SEM) micrograph. The presence of the lowest (0.1%) NaAlg concentration provokes a significant increasing the equilibrium degree solution (EDS) of hydrogel up 800 g/g ,and the extent of gel fraction increases as a function irradiation dose up to about 99 %. The hydrogels were also found to be sensitive to the ionic strength of medium. The FTIR spectra of hydrogels were shown crosslinking occurs between acrylamide and acrylic acid and pores structures in the hydrogel observed by using SEM.

Abstract: A novel nanofibrous membrane was used for removing Cu (II) from aqueous solutions. The poly (ethylene terephthalate) (PET) membranes were fabricated by electrospinning, and then grafted with acrylamide (AM) on the surface. The morphologies of the nanofiber was characterized by SEM, meanwhile, the chemical composition and element analysis on the membrane surface were measured by FT-IR and XPS, respectively. The Cu (II) adsorption experiment investigated the adsorption performance related to the pH value on. Equilibrium studies show that the adsorption process follows Langmuir model and the maximum adsorption capacity was estimated to be 183.25 [mg/g].