Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
8 results
Search Results
Item Extruded poly(ethylene-co-octene)/fly ash composites - Value added products from an environmental pollutant(Kluwer Academic Publishers, 2012) Anandhan, S.; Sundar, S.M.; Senthil, T.; Mahendran, A.R.; Shibulal, G.S.Fly ash (FA) is a by-product generated during combustion of coal and has caused serious environmental concerns. In an effort to utilize FA beneficially, we developed composites from an ethylene-octene random copolymer (EOC) and unmodified as well as surfacemodified class-F fly ash (MFA) by twin screw extrusion. Addition of 20 wt% of MFA to EOC improves its tensile strength by 150%; also, MFA improves stress at 100% and 300% strains (M100 and M300) of EOC. Thermal stability of EOC matrix is appreciably improved by the addition of either FA or MFA, while the melting behavior is not appreciably influenced by either. Fractography study reveals an improved adhesion between the EOC and MFA particles up to a filler loading of 20%, beyond which the adhesion between EOC and MFA is weakened causing a reduction in mechanical properties. The 'flammable' nature of EOC changes to 'self extinguishing' on addition of even 10 wt% of FA or MFA, as found out from LOI study. © Springer Science+Business Media B.V. 2012.Item LiClO4-doped plasticized chitosan and poly(ethylene glycol) blend as biodegradable polymer electrolyte for supercapacitors(Institute for Ionics, 2013) Sudhakar, Y.N.; Muthu, M.; Bhat, D.K.Biodegradable polymer electrolyte comprising the blend of chitosan (CS) and poly(ethylene glycol) (PEG) plasticized with ethylene carbonate and propylene carbonate, as host polymer, and lithium perchlorate (LiClO4), as a dopant, was prepared by solution casting technique. The ionic conductivity has been calculated using the bulk impedance obtained through impedance spectroscopy. The variation of conductivity and dielectric properties has been investigated as a function of polymer blend ratio, plasticizer content and LiClO4 concentration at temperature range of 298-343 K. The DSC thermograms show two broad peaks for CS/PEG blend and increased with increase in the LiClO4 content. The maximum conductivity has been found to be 1. 1 × 10-4 S cm-1 at room temperature for 70:30 (CS/PEG) concentration. The electric modulus of the electrolyte film exhibits a long tail feature indicative of good capacitance. The activation energy of all samples was calculated using the Arrhenius plot, and it has been found to be 0. 12 to 0. 38 eV. A carbon-carbon supercapacitor has been fabricated using this electrolyte, and its electrochemical characteristics and performance have been studied. The supercapacitor showed a fairly good specific capacitance of 47 F g-1. © 2012 Springer-Verlag.Item Statistical analysis of flexural modulus of cenospheres-reinforced, recycled poly(ethylene terephthalate) using Taguchi method(SAGE Publications Ltd, 2014) Prabhu, B.K.; Dudse, S.; Kulkarni, S.M.Statistical methods are playing an important role in the design and analysis of engineering experiments. One such method called Taguchi method is found to provide sufficient information to optimize a process with the use of minimum number of experiments. This article presents systematic application of Taguchi method for optimizing the process parameters of compression moulding process. The response under consideration is flexural modulus. The study includes the use of recycled polyethylene terephthalate reinforced with fly ash cenospheres. The use of these recycled materials is promising to reduce the cost of the engineering parts and help nature by increasing waste utilization. A model for flexural modulus is designed and verified through experiments. The outcome from analysis of variance brings out the facts that moulding pressure, moulding temperature and weight fraction of cenospheres are the three most significant parameters of flexural modulus, contributing 59.44, 21.45 and 7.75%, respectively. The optimum set values for these parameters are found to be 5 MPa, 50°C and 15%. The proposed quadratic model for flexural modulus proves to be well in agreement with the experimental results. © The Author(s) 2013.Item Thermodynamic miscibility and thermal and mechanical properties of poly(ethylene-co-vinyl acetate-co-carbon monoxide)/poly(vinyl chloride) blends(John Wiley and Sons Inc, 2015) SelvaKumar, M.; Mahendran, A.; Bhagabati, P.; Anandhan, S.This paper reports the miscibility and thermal and mechanical properties of solution cast binary blends of poly(ethylene-co-vinyl acetate-co-carbon monoxide) (EVACO) and poly(vinyl chloride) (PVC). The composition of these blends was varied from 10:90 to 90:10 of PVC/EVACO (w/w %). Fourier transform infrared spectroscopy revealed an extensive intermolecular attraction between the blend components, which accounts for their mutual solubility. The differential scanning calorimetry study revealed that the blend components are miscible with each other in all proportions as they exhibited a single glass transition temperature. Tensile strength, moduli, and thermal stabilities of these blends significantly improved with increasing proportion of PVC. © 2014 Wiley Periodicals, Inc.Item 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 LtdItem Supercapacitor studies of activated carbon functionalized with poly(ethylene dioxythiophene): Effects of surfactants, electrolyte concentration on electrochemical properties(Elsevier B.V., 2020) Sudhakar, Y.N.; Muthu, M.; Krishna Bhat, D.; Karazhanov, S.; Raghu, R.Electropolymerization of poly(ethylene dioxythiophene) (PEDOT) on activated carbon (AC) was performed using different surfactants such as anionic surfactant (sodium dodecyl sulfate), protonic surfactant (camphor sulphonic acid) and non-ionic surfactant (Triton) in 0.1 M H2SO4. The effects of concentration of different surfactants for electrodeposition of PEDOT on AC were analyzed using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and SEM techniques. Supercapacitors (SC) were fabricated using AC/PEDOT composite electrodes and 0.1 M H2SO4 as an electrolyte. The specific capacitance (Cs) values were calculated using CV at different concentrations of surfactants, electrolytes and variation of potential. The electrolyte containing 0.1 M H2SO4 and 0.02 M camphor sulphonic acid showed to have the highest specific capacitance value of 240 Fg?1 than other surfactant based SCs. Galvanostatic charge/discharge at varying current density were performed on SCs containing different surfactant based electrodes to study their cyclic stability. © 2020Item Performance Evaluation of Coir Geocells as Soil Retention System Under Dry and Wet Conditions(Springer Science and Business Media Deutschland GmbH info@springer-sbm.com, 2020) Chitrachedu, R.K.; Kolathayar, S.In the present study, coir is used to fabricate geocells and to construct model retaining walls for application in sloppy regions to retain the soil. The performance of coir geocells under dry and wet conditions during rainfall were evaluated by conducting laboratory model tests. The study presents horizontal and vertical deformation against surcharge load for different scenarios of reinforcement using geocells. A comparison was made between the performance of unreinforced slope, high-density polyethylene geocell retaining wall and coir geocell retaining wall to evaluate the potential of coir geocell over synthetic geocell as reinforcement. The roughness and absence of perforations in coir material resisted the movement and failure of the wall for a longer span. The horizontal displacement was more for coir geocell retaining wall compared to wall made of high density polyethylene (HDPE) geocells. This may be due to the interlocking effect in coir HDPE geocell as perforations provide contact between the sand particles. The inexpensive and easily disposable coir can be effectively used as reinforcement in the construction of a retaining wall. © 2020, Springer Nature Switzerland AG.Item Influence of multiwalled carbon nanotubes on the structure and properties of poly(ethylene-co-vinyl acetate-co-carbon monoxide) nanocomposites(John Wiley and Sons Inc, 2021) George, G.; Mahendran, A.R.; SelvaKumar, S.; Anandhan, S.In this work, composites of poly(ethylene-co-vinyl acetate-co-carbon monoxide) (EVACO)/surface-modified multiwalled carbon nanotubes (m-MWCNTs) were prepared using a solution casting technique. Acid treatment was employed for the surface modification of MWCNTs to improve the compatibility between polar EVACO and MWCNTs. The influences of m-MWCNTs on the crystalline, mechanical, thermal, and electrical properties of EVACO at very low filler loading were systematically evaluated. The presence of m-MWCNTs in the EVACO matrix influenced the crystallinity, and the respective changes were determined and quantified using dynamic scanning calorimetry and X-ray diffraction. The mechanical properties of the composites were improved remarkably by the addition of a minute quantity (0.05, 0.1, 0.15, 0.2, and 0.25 wt%) of m-MWCNTs. Additionally, m-MWCNTs in the EVACO matrix improved the thermal stability and electrical properties of EVACO. However, the filler loading is below the threshold loading of the fillers, and there was no drastic improvement in the electrical conductivity of the composite. © 2021 Society of Plastics Engineers.