Browsing by Author "Kundu, B."

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    Low Temperature Development of Nano-Hydroxyapatite from Austromegabalanus psittacus, Star fish and Sea urchin
    (2017) Komalakrishna, H.; Shine, Jyoth, T.G.; Kundu, B.; Mandal, S.
    The study focuses the preparation and characterization (physico-chemical and mechanical) of hydroxyapatite [Ca10(PO4)6(OH)2] (HAp) from naturally occurring dead marine species widely available in Arabian sea shore; namely Austromegabalanus psittacus, star fish (Asteroidea) and sea urchin (Echinoidea). All three marine species were found to be source of calcium carbonate in the form of aragonite (calcite) that crystallize in an organic matrix. The calcined aragonite was converted to nano-sized hydroxyapatite powder by chemical reaction with Ortho-phosphoric acid while maintaining stoichiometry, Ca/P = 1.67 at 80 �C. It was found from XRD that the powders were composed of pure HAp with average crystallite size of 10 nm. SEM, on the other hand, revealed nano-rod like elongated structures having a length in the range of 100 to 700 nm with an aspect ratio of 3.5. Further, the HAp powders were used to prepare cylindrical pellet samples by uni-axial pressing, sintered at 1100 �C temperature, made flat-parallel, polished and used finally for assessment of elastic modulus by compression test method. Primary results showed typical elastic modulus of pellets from Austromegabalanus psittacus is 3 GPa, star fish 2.1 GPa and sea urchin 2.3 GPa (L/D = 1.3 and strain rate = 0.01 mm/s). Thus, the powder synthesized from marine source could be a potential alternative for development of structural bio-ceramics and also can be used as scaffolds for bone or dental implants, because of its easy and economical fabrication. � 2017 Elsevier Ltd. All rights reserved.
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    Low Temperature Development of Nano-Hydroxyapatite from Austromegabalanus psittacus, Star fish and Sea urchin
    (Elsevier Ltd, 2017) Komalakrishna, H.; Shine Jyoth, T.G.; Kundu, B.; Mandal, S.
    The study focuses the preparation and characterization (physico-chemical and mechanical) of hydroxyapatite [Ca10(PO4)6(OH)2] (HAp) from naturally occurring dead marine species widely available in Arabian sea shore; namely Austromegabalanus psittacus, star fish (Asteroidea) and sea urchin (Echinoidea). All three marine species were found to be source of calcium carbonate in the form of aragonite (calcite) that crystallize in an organic matrix. The calcined aragonite was converted to nano-sized hydroxyapatite powder by chemical reaction with Ortho-phosphoric acid while maintaining stoichiometry, Ca/P = 1.67 at 80 °C. It was found from XRD that the powders were composed of pure HAp with average crystallite size of 10 nm. SEM, on the other hand, revealed nano-rod like elongated structures having a length in the range of 100 to 700 nm with an aspect ratio of 3.5. Further, the HAp powders were used to prepare cylindrical pellet samples by uni-axial pressing, sintered at 1100 °C temperature, made flat-parallel, polished and used finally for assessment of elastic modulus by compression test method. Primary results showed typical elastic modulus of pellets from Austromegabalanus psittacus is 3 GPa, star fish 2.1 GPa and sea urchin 2.3 GPa (L/D = 1.3 and strain rate = 0.01 mm/s). Thus, the powder synthesized from marine source could be a potential alternative for development of structural bio-ceramics and also can be used as scaffolds for bone or dental implants, because of its easy and economical fabrication. © 2017 Elsevier Ltd. All rights reserved.
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    Mechanical behaviour of additively manufactured bioactive glass/high density polyethylene composites
    (Elsevier Ltd, 2020) Jeyachandran, P.; Bontha, S.; Bodhak, S.; Balla, V.K.; Kundu, B.; Doddamani, M.
    Bioactive glass (BAG) is a well-known biomaterial that can form a strong bond with hard and soft tissues and can also aid in bone regeneration. In this study, BAG is added to a polymer to induce bioactivity and to realize fused filament fabrication (FFF) based printing of polymer composites for potential orthopaedic implant applications. BAG (5, 10, and 20 wt%) is melt compounded with high density polyethylene (HDPE) and subsequently extruded into feedstock filament for FFF-printing. Tensile tests on developed filaments reveal that they are stiff enough to resist forces exerted during the printing process. Micrography of printed HDPE/BAG reveals perfect diffusion of raster interface indicating proper selection of printing parameters. Micrography of freeze fractured prints shows the homogeneous distribution and good dispersion of filler across the matrix. The tensile, flexural, and compressive modulus of FFF-printed HDPE/BAG parts increases with filler addition. BAG addition to the HDPE matrix enhances flexural and compressive strength. The tensile and flexural behaviour of FFF-prints is comparable to injection molded counterparts. Property maps exhibit the merits of present study over the existing literature pertaining to desired bone properties and polymer composites used in biomedical applications. It is envisioned that the development of HDPE/BAG composites for FFF-printing can lead to possible orthopaedic implants and scaffolds to mimic the bone properties in customised anatomical sites or injuries. © 2020 Elsevier Ltd