Mithilesh Yadav

Synthesis and properties of a water soluble graft (chitosan-g-2-acrylamidoglycolic acid) copolymer.

The present paper reports the graft copolymerization of 2-acrylamidoglycolic acid onto chitosan by using potassium bromate/silver nitrate as an efficient redox initiator in an inert atmosphere. The effect of reaction conditions on grafting parameters i.e. grafting ratio, efficiency, conversion, add on, homopolymer and rate of grafting has been studied. Experimental results show that maximum grafting has been obtained at 0.4 g dm(-3) concentration of chitosan, 8.0×10(-2) mol dm(-3) concentration of 2-acrylamidoglycolic acid and 1.0×10(-3) mol dm(-3) concentration of hydrogen ion. It has also been observed that grafting ratio, add on, conversion, efficiency and rate of grafting increase up to 3.2×10(-3) mol dm(-3) of silver nitrate and 1.7×10(-2) mol dm(-3) of potassium bromate. Time (120 min) and temperature (40°C) were kept constant during reaction. The physicochemical properties of graft copolymer synthesized have been performed in terms of water swelling, metal ion sorption, flocculation and resistance to biodegradability with respect to the chitosan as a parent polymer. The graft copolymer has been characterized by Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis.

Synthesis, characterization and applications of graft copolymer (κ-carrageenan-g-vinylsulfonic acid)

The synthesis of graft copolymer (κ-carrageenan-g-vinylsulfonic acid) is carried out in nitrogen atmosphere using potassium peroxymonosulfate (PMS) and malonic acid (MA) as redox system. The effect of reaction variables including the concentration of vinylsulfonic acid 1.3×10(-2) to 6.7×10(-2) mol dm(-3), PMS 4×10(-3) to 20×10(-3) mol dm(-3), MA 1.6×10(-3) to 4.8×10(-3) mol dm(-3), sulfuric acid 1×10(-3) to 8×10(-3) mol dm(-3), κ-carrageenan 0.4-1.8 g dm(-3) as well as time duration 60-180 min and temperature 25-45 °C has been studied. The water swelling capacity of graft copolymer is investigated. Flocculation property for both coking and non-coking coals is studied for the treatment of coal mine waste water. The graft copolymer has been characterized by FTIR and thermogravimetric analysis.

Grafting of N-(hydroxymethyl) acrylamide on to κ-carrageenan: synthesis, characterization and applications.

The synthesis of graft copolymer [κ-carrageenan-g-N-(hydroxymethyl) acrylamide] is carried out in nitrogen atmosphere using potassium peroxymonosulphate (PMS) and glycolic acid (GA) as redox system. The effect of reaction variables including the concentration of N-(hydroxymethyl) acrylamide (4 × 10(-2) to 36 × 10(-2))mol dm(-3), PMS (4 × 10(-3) to 20 × 10(-3))mol dm(-3), GA (1.6 × 10(-3) to 4.8 × 10(-3)) mol dm(-3), sulphuric acid (4 × 10(-3) to 12 × 10(-3)) mol dm(-3), κ-carrageenan (0.6-1.8) g dm(-3) as well as time duration (60-180)min and temperature (25-45)°C has been studied. The physicochemical properties of graft copolymer synthesized have been performed in terms of water swelling, metal ion sorption and flocculation with respect to the κ-carrageenan as a parent polymer. The graft copolymer has been characterized by FTIR and thermogravimetic analysis.

Graft (partially carboxymethylated guar gum-g-poly vinyl sulfonic acid) copolymer: From synthesis to applications

The aim of the paper is to study the physico-chemical phenomenon of synthesized graft copolymer (carboxymethylated guar gum-g-vinylsulfonic acid). The reaction optimum conditions for grafting has also been determined by studying the effect of vinylsulfonic acid, hydrogen ion, peroxymonosulphate, glycolic acid concentration and carboxymethylated guar gum along with time and temperature. Experimental results show that maximum grafting has been obtained at 1.8 g dm(-3) concentration of partially carboxymethylated guar gum and 5.3 × 10(-2) mol dm(-3) concentration of vinylsulfonic acid. It has been observed that grafting ratio, add on, conversion, efficiency increase up to 4.0 × 10(-3) mol dm(-3) of hydrogen ion, 4 × 10(-3) mol dm(-3) of glycolic acid, 14 × 10(-3) mol dm(-3) of peroxymonosulphate and 35 °C of temperature. Grafted copolymer has been characterized by FTIR spectroscopy and thermogravimetric analysis. Water swelling, flocculating, metal ion uptake and resistance to biodegradability properties of partially carboxymethylated guar gum-g-vinylsulfonic acid have been determined.

Studies on graft copolymerization of gellan gum with N,N-dimethylacrylamide by the redox system.

The present paper reports the graft copolymerization of N,N-dimethylacrylamide onto gellan gumby free radical polymerization using potassium peroxymonosulphate/sarbose redox system in an inert atmosphere. The reaction conditions for maximum grafting have been optimized by varying the reaction variables, including the concentration of N,N-dimethylacrylamide(4.0×10(-2)-20×10(-2) mol dm(-3)), potassium peroxymonosulphate (0.6×10(-2)-1.4×10(-2)mol dm(-3)), sarbose (0.4×10(-3)-3.6×10(-3) mol dm(-3)), sulphuric acid (2.0×10(-3)-10×10(-3) mol dm(-3)), gellan gum (0.6-1.4 g dm(-3)) along with time duration (60-180 min) and temperature (25-45°C).Water-swelling capacity, metal ion sorption and flocculation studies of synthesized graft copolymer have been performed with respect to the parent polymer. The graft copolymer has been characterized by FTIR spectroscopy and thermogravimetric analysis.

Graft Copolymer (Guar Gum-G-Poly 2-Acrylamidoglycolic Acid): Synthesis, Swelling and Flocculation Behaviors

The present paper reports the modification of guar gum through the grafting of 2-acrylamidoglycolic acid by free radical polymerization using an efficient potassium peroxydiphosphate/thioacetamide redox system in nitrogen atmosphere. The reaction conditions for maximum grafting have been optimized by varying the reaction variables including the concentration of 2-acrylamidoglycolic acid (5.3×10 -2 mol dm -3 ), potassium peroxydiphosphate (1.2×10 -2 mol dm -3 ), thioacetamide (TA) (2×10 -3 mol dm -3 ), sulphuric acid (4×10 -3 mol dm -3 ), guar gum (1 g dm −3 ) along with time duration (150 min) and temperature (35°C). Water swelling capacity and flocculation and studies of synthesized graft copolymer have been performed with respect to the parent polymer. The graft copolymer has been characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis.