The Experts below are selected from a list of 5439 Experts worldwide ranked by ideXlab platform
Rashmi Sanghi - One of the best experts on this subject based on the ideXlab platform.
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grafting of Methylmethacrylate on to the plant seed galactomannans using potassium persulphate ascorbic acid redox pair
Reactive & Functional Polymers, 2006Co-Authors: Vandana Singh, Ashutosh Tiwari, Pankaj Shukla, Shailendra Pratap Singh, Rashmi SanghiAbstract:Abstract K2S2O8/ascorbic acid initiated grafting of Methylmethacrylate on to guar (Cyanaposis tetragonolobus) seed galactomannan has been studied gravimetrically at 35 ± 0.2 °C in presence of atmospheric oxygen and the conditions were optimized. Grafted guar gum was characterized using FTIR, XRD, 1H NMR and TGA analysis. Under optimal grafting conditions for the guar gum, five other wildly sourced seed galactomannans from Cassia abbreviata, Cassia javanica, Cassia reticulata, Ipomoea palmata and Ipomoea hedracea were grafted with Methylmethacrylate in order to study the effect of structural diversity in the galactomannans on grafting and also for the possible commercial exploitation of these non-conventional galactomannans from Cassia and Ipomoea seeds. Results for all the galactomannans are compared and discussed.
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microwave synthesized chitosan graft poly Methylmethacrylate an efficient zn2 ion binder
Carbohydrate Polymers, 2006Co-Authors: Vandana Singh, Devendra Narayan Tripathi, Ashutosh Tiwari, Rashmi SanghiAbstract:Abstract Microwave promoted grafting of Methylmethacrylate on to the chitosan has been optimized. Chitosan-graft-poly(Methylmethacrylate) (Ch-g-PMMA) could be synthesized with 160% grafting using 80% MW power in 2 min at (MMA) 0.17 M, (Chitosan) 0.1 g/25 ml. While for the same concentration of the Methylmethacrylate and the chitosan, 105% grafting was observed when K2S2O8/ascorbic acid redox initiator used in presence of Ag+ (catalyst) and atmospheric oxygen (co-catalyst) at 35±0.2 °C. K2S2O8/ascorbic acid redox system is for the first time used for grafting Methylmethacrylate on to the chitosan. The representative graft copolymer was characterized by Fourier transform-infrared, thermo gravimetric analysis and X-ray diffraction measurement, taking chitosan as reference. The effect of reaction variables as monomer/chitosan concentration, microwave power and exposure time on the graft co-polymerization was studied. A probable mechanism for grafting under microwave heating has been proposed. Viscosity of the grafted chitosan solutions and water/saline retention for the grafted chitosans were determined and compared with that of the chitosan. The microwave synthesized graft copolymer was found to have efficient adsorption ability for Zn2+ ions in aqueous solution. Effect of pH and Zn2+ concentration on adsorption was also studied.
Leo H Koole - One of the best experts on this subject based on the ideXlab platform.
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mechanical behaviour of a new acrylic radiopaque iodine containing bone cement
Biomaterials, 2004Co-Authors: Catharina S J Van Hooycorstjens, Leon E Govaert, A Anne B Spoelstra, Sjoerd K Bulstra, Gwendolyn M R Wetzels, Leo H KooleAbstract:In total hip replacement, fixation of a prosthesis is in most cases obtained by the application of methacrylic bone cements. Most of the commercially available bone cements contain barium sulphate or zirconium dioxide as radiopacifier. As is shown in the literature, the presence of these inorganic particles can be unfavourable in terms of mechanical and biological properties. Here, we describe a new type of bone cement, where X-ray contrast is obtained via the introduction of an iodine-containing methacrylate copolymer; a copolymer of Methylmethacrylate and 2-[4-iodobenzoyl]-oxo-ethylmethacrylate (4-IEMA) is added to the powder component of the cement. The properties of the new I-containing bone cement (I-cement) are compared to those of a commercially available bone cement, with barium sulphate as radiopacifier (B-cement). The composition of the I-cement is adjusted such that similar handling properties and radiopacity as for the commercial cement are obtained. In view of the mechanical properties, it can be stated that the intrinsic mechanical behaviour of the I-cement, as revealed from compression tests, is superior to that of B-cement. Concerning the fatigue behaviour it can be concluded that, though B-cement has a slightly higher fatigue crack propagation resistance than I-cement, the fatigue life of vacuum-mixed I-cement is significantly better than that of B-cement. This is explained by the presence of BaSO4 clumps in the commercial cement; these act as crack initiation sites. The mechanical properties (especially fatigue resistance) of the new I-cement warrant its further development toward clinical application.
Imre Dekany - One of the best experts on this subject based on the ideXlab platform.
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synthesis and utilization of poly Methylmethacrylate nanocomposites based on modified montmorillonite
Arabian Journal of Chemistry, 2017Co-Authors: Ahmed M Youssef, Farag Malhat, A Abdel A Hakim, Imre DekanyAbstract:Abstract Poly (Methylmethacrylate) nanocomposite was prepared via in-situ emulsion polymerization (PMMA/Mt-CTA). The modified montmorillonite (Mt-CTA) is used as hosts for the preparation of poly (Methylmethacrylate) nanocomposites with basal distance 1.95 nm. Moreover, exfoliated nanocomposite was characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC). The fashioned nanocomposites exhibited better thermal stability than pristine PMMA which make it suitable for packaging applications. Furthermore, this nanocomposite reveals tremendous affinity for removing pesticides from aquatic solutions. The data obtained from GC/ECD gas liquid chromatography illustrated that the removal efficiency of PMMA/Mt-CTA nanocomposites for organochlorine pesticides (OCPs) varied from 73.65% to 99.36% that make it as a new method for water treatment. Also, the antimicrobial activity of the Mt-CTA and PMMA/Mt-CTA nanocomposites was evaluated by the inhibitory zone tests and revealed good activity against Escherichia coli and Staphylococcus aureus , which makes it suitable materials for packaging applications.
Sjoerd K Bulstra - One of the best experts on this subject based on the ideXlab platform.
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mechanical behaviour of a new acrylic radiopaque iodine containing bone cement
Biomaterials, 2004Co-Authors: Catharina S J Van Hooycorstjens, Leon E Govaert, A Anne B Spoelstra, Sjoerd K Bulstra, Gwendolyn M R Wetzels, Leo H KooleAbstract:In total hip replacement, fixation of a prosthesis is in most cases obtained by the application of methacrylic bone cements. Most of the commercially available bone cements contain barium sulphate or zirconium dioxide as radiopacifier. As is shown in the literature, the presence of these inorganic particles can be unfavourable in terms of mechanical and biological properties. Here, we describe a new type of bone cement, where X-ray contrast is obtained via the introduction of an iodine-containing methacrylate copolymer; a copolymer of Methylmethacrylate and 2-[4-iodobenzoyl]-oxo-ethylmethacrylate (4-IEMA) is added to the powder component of the cement. The properties of the new I-containing bone cement (I-cement) are compared to those of a commercially available bone cement, with barium sulphate as radiopacifier (B-cement). The composition of the I-cement is adjusted such that similar handling properties and radiopacity as for the commercial cement are obtained. In view of the mechanical properties, it can be stated that the intrinsic mechanical behaviour of the I-cement, as revealed from compression tests, is superior to that of B-cement. Concerning the fatigue behaviour it can be concluded that, though B-cement has a slightly higher fatigue crack propagation resistance than I-cement, the fatigue life of vacuum-mixed I-cement is significantly better than that of B-cement. This is explained by the presence of BaSO4 clumps in the commercial cement; these act as crack initiation sites. The mechanical properties (especially fatigue resistance) of the new I-cement warrant its further development toward clinical application.
Gwendolyn M R Wetzels - One of the best experts on this subject based on the ideXlab platform.
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mechanical behaviour of a new acrylic radiopaque iodine containing bone cement
Biomaterials, 2004Co-Authors: Catharina S J Van Hooycorstjens, Leon E Govaert, A Anne B Spoelstra, Sjoerd K Bulstra, Gwendolyn M R Wetzels, Leo H KooleAbstract:In total hip replacement, fixation of a prosthesis is in most cases obtained by the application of methacrylic bone cements. Most of the commercially available bone cements contain barium sulphate or zirconium dioxide as radiopacifier. As is shown in the literature, the presence of these inorganic particles can be unfavourable in terms of mechanical and biological properties. Here, we describe a new type of bone cement, where X-ray contrast is obtained via the introduction of an iodine-containing methacrylate copolymer; a copolymer of Methylmethacrylate and 2-[4-iodobenzoyl]-oxo-ethylmethacrylate (4-IEMA) is added to the powder component of the cement. The properties of the new I-containing bone cement (I-cement) are compared to those of a commercially available bone cement, with barium sulphate as radiopacifier (B-cement). The composition of the I-cement is adjusted such that similar handling properties and radiopacity as for the commercial cement are obtained. In view of the mechanical properties, it can be stated that the intrinsic mechanical behaviour of the I-cement, as revealed from compression tests, is superior to that of B-cement. Concerning the fatigue behaviour it can be concluded that, though B-cement has a slightly higher fatigue crack propagation resistance than I-cement, the fatigue life of vacuum-mixed I-cement is significantly better than that of B-cement. This is explained by the presence of BaSO4 clumps in the commercial cement; these act as crack initiation sites. The mechanical properties (especially fatigue resistance) of the new I-cement warrant its further development toward clinical application.
