Selective Preconcentration of U(VI) and Th(IV) in Trace and Macroscopic Levels Using Malonamide Grafted Polymer from Acidic Matrices

2005 ◽  
Vol 150 (3-4) ◽  
pp. 297-304 ◽  
Author(s):  
Chinthalapati Siva Kesava Raju ◽  
Mandakolathur S. Subramanian
2020 ◽  
Vol 16 (9) ◽  
pp. 1404-1410
Author(s):  
Rishabha Malviya

Background: In the previous study, investigators have synthesized acrylamide grafted and carboxymethylated derivatives of neem gum and evaluated their potential in the formulation of nanoparticles. In continuation of previous work, authors have evaluated neem gum polysaccharide (NGP), acrylamide grafted neem gum polysaccharide (NGP-g-Am) and carboxymethylated neem gum polysaccharide (CMNGP) as binding agent in the tablet dosage form. Methods: Diclofenac sodium was used as a model drug while microcrystalline cellulose and talc were used as excipient in the preparation of granules employing wet granulation technique. NGP, NGP-g-Am and CMNGP were utilized as binding agent in the preparation of granules. Prepared granules were characterized for various pre-compression and post-compression parameters. Results and Discussion: Binding agents were used in the concentration of 4-24%w/w. NGP incorporated granules showed more bulk density and lower values of tapped density, Carr’s index, bulkiness, Hausner’s ratio and angle of repose as compared to NGP-g-Am consisting granules. NGP-g-Am consisting tablets showed more hardness and zero friability as compared to NGP based tablets. Drug content was found lower for the tablets having grafted polymer in place of NGP. CMNGP were also utilized to prepare granules but granules were not be able to compress keeping all the compacting parameters same as used in the case of NGP and NGP-g-Am consisting granules. NGP and NGP-g-Am were able to sustain drug release up to 6 and 8 h, respectively. Conclusion: It can be concluded that NGP-g-Am induces better properties when used as a binder in the tablet formulation than native polymer, while CMNGP cannot be utilized as a binding agent in the preparation of a tablet.


1956 ◽  
Vol 29 (1) ◽  
pp. 99-105 ◽  
Author(s):  
G. F. Bloomfield ◽  
F. M. Merrett ◽  
F. J. Popham ◽  
P. Mc L. Swift

Abstract Graft polymers result when vinyl monomers are polymerized in the presence of natural rubber, either in solution or as latex, and some of the polymeric chains become attached to the rubber molecules. The properties of the natural rubber can be widely modified according to the nature and the amount of the grafted polymer. The polymer-modified natural rubber appears to be produced by direct growth of polymer chains on to rubber molecules rather than by a transfer reaction involving the rubber. Graft polymers of styrene and methyl methacrylate with natural rubber can be compounded and cured to give light-colored articles of good tensile strength, and rubber-methyl methacrylate graft polymers have outstanding flex-cracking and fatigue resistance.


2015 ◽  
Vol 7 (40) ◽  
pp. 22203-22212 ◽  
Author(s):  
Albert Albert ◽  
Alejandro O. Barnett ◽  
Magnus S. Thomassen ◽  
Thomas J. Schmidt ◽  
Lorenz Gubler

2000 ◽  
Vol 112 (3) ◽  
pp. 1565-1573 ◽  
Author(s):  
P. Sotta ◽  
A. Lesne ◽  
J. M. Victor

Nanomaterials ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 883 ◽  
Author(s):  
Jose Sanchez-Salvador ◽  
Ana Balea ◽  
M. Monte ◽  
Angeles Blanco ◽  
Carlos Negro

Cellulose and chitin are the most abundant polymeric materials in nature, capable of replacing conventional synthetic polymers. From them, cellulose nano/microfibers (CNFs/CMFs) and chitosan are obtained. Both polymers have been used separately in graft copolymerization but there are not many studies on the use of cellulose and chitosan together as copolymers and the reaction mechanism is unknown. In this work, the reaction mechanism to produce nano/microcellulose-graft-chitosan polymer has been studied. Recycled cellulose pulp was used, with and without a 2,2,6,6-tetramethylpiperidin-1-oxyl-radical (TEMPO)-mediated oxidation pretreatment, to produce CNFs and CMFs, respectively. For chitosan, a low-molecular weight product dissolved in an acetic acid solution was prepared. Grafted polymers were synthesized using a microwave digester. Results showed that TEMPO-mediated oxidation as the cellulose pretreatment is a key factor to obtain the grafted polymer CNF-g-CH. A reaction mechanism has been proposed where the amino group of chitosan attacks the carboxylic group of oxidized cellulose, since non-oxidized CMFs do not achieve the desired grafting. 13C NMR spectra, elemental analysis and SEM images validated the proposed mechanism. Finally, CNF-g-CH was used as a promising material to remove water-based inks and dyes from wastewater.


1995 ◽  
Vol 11 (2) ◽  
pp. 313-315 ◽  
Author(s):  
Xian Ren CHEN ◽  
Yuqi FENG ◽  
Hisanori IMURA ◽  
Kazuhisa HIRATANI ◽  
Kousaburo OHASHI

2007 ◽  
Vol 97 (3) ◽  
pp. 574-587 ◽  
Author(s):  
Bryan R. Coad ◽  
Bradley M. Steels ◽  
Jayachandran N. Kizhakkedathu ◽  
Donald E. Brooks ◽  
Charles A. Haynes

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