Browsing by Author "Amit Basak"

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Cardanol Functionalized Carboxylated Acrylonitrile Butadiene Rubber for Better Processability, Technical Properties and Biocompatibility
(Springer New York LLC, 2019) Satyajit Samantarai; Ahindra Nag; Nitesh Singh; Debabrata Dash; Amit Basak; Golok B. Nando; Narayan Ch. Das
The present investigation deals with the latex stage functionalization of carboxylated acrylonitrile butadiene rubber (XNBR) by chemically grafting cardanol onto its backbone main chain to impart multifunctional characteristics to it. The grafting of cardanol onto XNBR in the latex stage has been accomplished successfully using benzoyl peroxide (BPO) as a free radical initiator. Cardanol grafted XNBR (C-g-XNBR) exhibited an increase in molecular weight (7.5%) with an increase in PDI (polydispersity index). The optimum grafting parameters were found to be of 1 phr BPO with 15 phr cardanol at a reaction temperature of 80 °C and a reaction time of 10 h using “Taguchi methodology”. The maximum percentage grafting (PG) and grafting efficiency (GE) were estimated to be 13.8 and 92.8%, respectively at the optimum combination of the reaction parameters. Differential scanning calorimetry and dynamic mechanical analysis results exhibited a decrease in Tg value for the functionalized elastomer. Thermogravimetric analysis displayed an increase in the thermal stability of C-g-XNBR. MTT [3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide] assay and hemolysis studies proved that functionalized rubber as biocompatible. Moreover, functionalized XNBR exhibited a potential bactericidal effect against Staphylococcus aureus and Escherichia coli strains. Fire and flame retardancy study revealed an increased LOI (limiting oxygen index) for C-g-XNBR. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
Chemical modification of nitrile rubber in the latex stage by functionalizing phosphorylated cardanol prepolymer: A bio-based plasticizer and a renewable resource
(SAGE Publications Ltd, 2019) Satyajit Samantarai; Ahindra Nag; Nitesh Singh; Debabrata Dash; Amit Basak; Golok B Nando; Narayan Ch Das
The present investigation deals with the functionalization of acrylonitrile butadiene rubber (NBR) by chemically grafting phosphorylated cardanol prepolymer (PCP) onto its backbone chain. The grafting of PCP onto NBR was accomplished in the latex stage successfully using benzoyl peroxide as the free radical initiator. The functionalized NBR (PCP-g-NBR) is characterized by ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and gel permeation chromatography. PCP-g-NBR exhibited an increase in molecular weight (4.4%) with an increase in the polydispersity. The grafting parameters have been optimized using “Taguchi L 9 table” and the optimum conditions were found to be “3 phr of initiator concentration, 15 phr of the PCP concentration, reaction temperature of 70°C and reaction time of 6 h.” The percentage grafting and grafting efficiency were calculated to be 7.28 and 80.37%, respectively, under optimum processing conditions. The PCP-g-NBR exhibited a reduction in Wallace plasticity number as well as the Mooney viscosity and an enhanced plasticity retention index (PRI) as compared to neat NBR. The rheological measurements exhibited a higher flow behavior index for PCP-g-NBR than the NBR itself. Differential scanning calorimetry and dynamic mechanical analysis results exhibited a decrease in glass transition temperature on functionalization of NBR confirming enhanced plasticization. Thermogravimetric analysis results displayed an increase in thermal stability of the functionalized NBR than that of virgin NBR. The physico-mechanical properties of the PCP-g-NBR vulcanizates were at par with or even better than the neat NBR vulcanizates. 3-(4,5-Dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide assay and hemolysis studies indicated NBR and PCP-g-NBR are nontoxic and biocompatible. © The Author(s) 2018.