Radiation crosslinked polyvinyl alcohol/polyvinyl pyrrolidone/acrylic acid hydrogels: swelling,crosslinking and dye adsorption study

Iranian Polymer Journal - Hydrogels were produced from mixtures of polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), and acrylic acid (AAc) using γ-radiation at doses of 3, 7, and...     

The Role of Coagulants on the Preparation of Dipped film from Radiation Vulcanized Natural Rubber Latex

The effect of coagulants on the preparation of dipped film with good physical properties was studied. In order to optimize various parameters like coagulant concentration, latex concentration, and former dipping time in latex and coagulant, the effect of coagulant on the physical properties of radiation vulcanized natural rubber latex film was evaluated. Calcium nitrate, calcium chloride, and ammonium nitrate were used as the coagulant by dissolving either in water or ethanol. Calcium nitrate solution was found to be the best one among the coagulants used.     

Study on the Properties of Blend Rubber Between Grafted Rubber Latex and Natural Rubber Latex by Gamma Radiation

Blend rubber films were prepared by mixing styrene grafted rubber latex and natural rubber latex (NRL) with varying proportions by gamma radiation from Co-60 source at room temperature. Tensile strength, modulus at 500% elongation, elongation at break, permanent set, and swelling ratio were measured. Tensile strength and modulus at 500% elongation attain maximum at 8 kGy radiation dose for blend rubber films. The increase in tensile strength is insignificant, but modulus increases from 5.61 to 7.46 MPa with increased proportion of grafted rubber latex from 40 to 70% in the blend at this radiation dose. Elongation at break, permanent set, and swelling ratio of blend rubber decreases with increase in radiation dose as well as proportion of grafted rubber.     

Studies on the Physicochemical Properties of Natural Rubber/Polyethylene Blends and the Impact of Radiation on Their Properties

NR and Polyethylene (PE) were blended at different compositions of PE, like 00, 35, 50, 65, 85 and 100% by extrusion method and then the blend films were made by hot press. The blends, NR and PE films were irradiated and their mechanical properties were investigated before and after leaching. Blend compositions were optimized and found that the 50–65% PE blends give the best quality. It is also found that 5–8 kGy radiation doses are optimal for improved properties of blends. Leaching enhances mechanical properties and lower radiation doses give more enhanced mechanical properties compared to unleached one.     

Characterization of Poly(Vinyl Alcohol) and Poly(Vinyl Pyrrolidone) Co-polymer Blend Hydrogel Prepared by Application of Gamma Radiation

Hydrogel is prepared from a poly(vinyl pyrrolidone) (PVP) and poly(vinyl alcohol) (PVA) blend solution by gamma radiation with a ₆₀Co λ source at room temperature. Properties of the prepared hydrogel, such as gel fraction, gel strength swelling ratio, equilibrium water content, and water absorption in room temperature, were investigated. Blending hydrogel with PVP and PVA obviously increased the gel strength and decreased the swelling ratio of hydrogel. It was observed that the gel fraction increased while the swelling ratio and water content decreased with increased radiation dose, but gel strength increased up to a certain radiation dose and then decreased. The percentage of water absorption at room temperature increased with time but after a certain time it became steady and decreased with radiation dose.     

Effect of Kappa-Carrageenan on the Properties of Poly (Vinyl Pyrrolidone) Hydrogel Prepared by the Application of Radiation

Poly (vinyl pyrrolidone) hydrogels with kappa-carrageenan (KC) were synthesized by γ-ray irradiation. The conditions of synthesis such as variation of total radiation doses and concentration of KC were determined. The properties of the prepared hydrogels, such as gel strength, gel fraction, swelling ratio, and water absorption were evaluated. Gel strength and gel fraction attain maximum up to a certain dose but swelling ratio and water absorption decrease with increased total doses. Gel strength, swelling ratio, and water absorption increase with an increase in the concentration of KC but the gel fraction reduces.     

Rheological Studies of NR/PVP Blends and Impact of Concentration and Speed Range on Their Properties

Natural Rubber Latex (NRL) and Polyvinyl pyrolidone (PVP) blends with different PVP concentrations were prepared and rheological properties of NRL/PVP blends have been investigated at different speed range. Significant changes of behaviors are found with increased PVP in blends. Yield stress increases with increased PVP in blends. The increasing trend of stress increases with PVP content in blend. Shear stress and yield stress increase with increased speed range. Change of nature of rheogram of NRL with PVP indicates the interaction between NRL and PVP. Increasing speed range, the decreasing trend of viscosity indicates the orderliness of molecular segments in blends.     

Improvement of Physicochemical Properties of Natural Rubber and Polyvinyl Alcohol Blends by Radiation Vulcanization

Variable compositions of natural rubber latex (NRL) and polyvinyl alcohol (PVA) have been blended. The contents of PVA in the blends were varied from 0.5 phr to 3.0 phr and the total solids contents of NRL was fixed to 50%. The blends were irradiated at different irradiation doses (0–20 kGy) in the presence of normal butylacrylate (n-BA). The permanent set; swelling ratio and elongation at break point of the blended films at all compositions decrease with the increase of radiation doses whereas increase is observed in cross-linking density, gel content, tensile strength and modulus. Sharp changes of all the properties were observed between 3–5 kGy radiation doses. On the other hand, at higher radiation doses, ≥ 5 kGy, the permanent set, swelling ratio, gel content did not show any appreciable change whereas cross-linking density, tensile strength, modulus and elongation at break point are changed. The maximum cross-linking density of blend is observed with 2.0 phr PVA at 12 kGy radiation. The highest value of modulus and tensile strength of the same blend are found at 10 kGy and 5 kGy respectively. Blends with 2.0 phr PVA for all compositions proved to be optimum for improving varies properties at 5–12 kGy radiation doses.     

Efficient removal of methyl orange from aqueous solution using amidoxime adsorbent

The amidoxime adsorbent was prepared by radiation grafting of acrylonitrile on non-woven polyethylene followed by chemical treatment with hydroxyl amine hydrochloride. The prepared amidoxime adsorbent was used for adsorption of methyl orange (MO) from aqueous solution. The effect of different conditions such as contact time, pH and initial metal ion concentration on the adsorption capacity was investigated. Pseudo-first-order and pseudo-second-order equations were used to study the kinetic adsorption data. A Langmuir isotherm model was used to investigate the equilibrium experimental data. The monolayer saturation adsorption capacity of the adsorbent for MO, as determined from the Langmuir equation, was 142 mg/g of the adsorbent. Moreover, desorption and reuse of the adsorbent film showed satisfactory results. Large-scale recycling of the adsorbent will reduce the production cost, and thereby make the practical application of the adsorbent economically feasible.

Abbreviations: Acrylonitrile - AN, Polyethylene - PE, Methylene Orange - MO     

Irradiated sodium–alginate/poly(ethylene oxide) blend films improved by methyl acrylate monomer

Sodium alginate (SA)‐based poly(ethylene oxide) (PEO) blend films were improved by methyl acrylate (MA) monomer and γ irradiation toward practical application. The films were prepared by a casting method and modified by glycerol (Gol) and mustard oil (MO). The SA‐based films were successfully produced with γ irradiation (12 kGy) with 10% PEO, 15% Gol, 20% MO, and 7% MA on a mass basis as optimized. The tensile strength (TS), tear strength (TT), elongation at break (EB), Young's modulus, moisture content, water vapor permeability (WVP), and structural properties of the blended films were determined. The thermal properties of the films were characterized by thermogravimetric analysis, dynamic mechanical analysis, and differential scanning calorimetry, and the structural features were examined with Fourier transform infrared spectroscopy. The ultimate results of this study show a rather remarkable enhancement in the tensile properties (30% TS and 67% TT) and reduction in EB (40%) of the SA‐based films with MA addition and γ irradiation. The as‐prepared SA‐based films demonstrated considerable reductions in the moisture content and WVP and also conferred a desired stability of the films. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43562.