Faculty of Engineering and Built Environment
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Item The effect of treatment on kenaf fiber using green approach and their reinforced epoxy composites(Elsevier, 2016) Kotharangannagari, Venkata Krishna; Kanny, KrishnanIn this study we show the novel treatment (surface modification) of kenaf fiber using amino acids and the studies of kenaf fiber reinforced epoxy composites. The kenaf fiber was treated at room temperature for 24 h, using two amino acids namely glutamic acid (acid) and lysine (base). Thermogravimetric analysis (TGA) of the treated kenaf fiber (glutamic acid treated and lysine treated) showed more weight loss than compared to untreated fiber. The tensile studies of the composites suggested improved me-chanical properties in both the cases, glutamic acid treated and lysine treated kenaf fiber than compared to untreated samples. Dynamic mechanical analysis (DMA) of the composites suggested that the storage modulus, loss modulus and tand were most influenced by the chemical treatment. The morphological studies of the kenaf fibers before and after treatment were examined using scanning electron microscopy (SEM) and revealed that the chemical treatment for 24 h, removed any impurity from thefibers surface. In addition, morphological studies of fractured mechanical testing composite samples using SEM were performed to understand the de-bonding of fiber/matrix adhesion. The results, confirmed that the lysine treatment is more effective than the glutamic acid treatment on kenaf fibers.Item Biodegradable hybrid nanocomposites of starch/lysine and ZnO nanoparticles with shape memory properties(Elsevier, 2016) Kotharangannagari, Venkata Krishna; Kanny, KrishnanIn food packing applications; the research works have been focused on the development of biodegradable pack-ing materials by using biopolymers such as starch, carrageenan, agar, and gelatine to replace with petroleum-based non-biodegradable polymers. In this present work we studied novel synthesis of biodegradable hybrid nanocomposites using starch, amino acid (lysine), polypropylene glycol (PPG) and ZnO nanoparticles (NPs) and their shape memory properties. A series of hybrid nanocomposites were prepared by solution casting meth-od, with various ZnO nanoparticles content such as 0 wt%, 1 wt%, 3 wt% and 5 wt% by keeping peptide content constant and varying the ratio between starch and ZnO nanoparticles content. The thermogravimetric analysis (TGA) of the hybrid nanocomposites suggested increased thermal stability with increasing ZnO nanoparticles content. The solubility of the hybrid nanocomposites in H2O is decreased with increasing ZnO nanoparticles con-tent. The moisture content in the hybrid nanocomposites is decreased with increasing ZnO nanoparticles content. The mechanical properties of the materials were increased with increasing ZnO nanoparticle content. Further-more, the hybrid nanocomposites showed a shape memory properties by placing the sample at room tempera-ture and then at 55 °C. The morphology of the hybrid nanocomposites was revealed using scanning electron microscopy (SEM). We believe that these biodegradable hybrid nanocomposite films can be useful in food pack-ing applications.Item Barrier and biodegradable properties of corn starch-derived biopolymer film filled with nanoclay fillers(SAGE Publications, 2016-12-18) Mohan, T. P.; Devchand, Kay; Kanny, KrishnanThe objective of this work is to study the effect of nanoclay fillers on the biodegradation and barrier properties of corn starch polymer-based biofilm. Starch derived from corn plant source was used to prepare a biofilm by plasticization method. The barrier properties, namely, water absorption, moisture permeation, oxygen permeation and swelling of unfilled and nanoclay-filled corn starch biofilms were examined. The results indicate: ∼22% reduced water absorption, 40% reduced moisture uptake, 30% reduced oxygen permeation and 31% reduced swelling for 2–3 wt.% nanoclay-filled biofilm, when compared with unfilled biopolymer. The biodegradation result of unfilled and nanoclay-filled film series indicates that the nanoclay addition delays the biodegradation and is a function of nanoclay content in the film. The tensile, dynamic mechanical analysis and biodegradable studies were conducted on the biopolymers before and after water absorption, and the result shows that the nanoclay-filled biopolymer increased these properties when compared with unfilled biopolymer even after water absorption and is dependent on the nanocomposite structure and morphology as examined by X-ray diffraction and transmission electron microscopy analysis.Item Novel-porous-Ag0 nanocomposite hydrogels via green process for advanced antibacterial applications(Wiley Online Library, 2014-12) Vimala, K.; Kanny, Krishnan; Varaprasad, Kokkarachedu; Kumar, N. Mithil; Reddy, Golamari SivaSilver nanoparticles (NPs) antibacterial characteristics were depends on its particle stabilization, particles size and nucleation agent. In this study, we report on green process of porous silver nanocomposite hydrogels for advanced antibacterial applications. The porous poly(acrylamide) (PAM) hydrogels were developed employing sucrose as porogenator. Silver NPs were nucleated with natural biomass Neem (Azadirachta indica) leaf extracts within the porous hydrogel networks. The formation of silver NPs in the porous hydrogels was confirmed by ultraviolet-visible spectroscopy, fourier transform infrared spectroscopy, X-ray diffraction, and thermo gravimetric analysis. Morphological studies done by scanning electron microscopy and transmission electron microscopy showed that the hydrogels were porous in nature and stabilization of NPs, size, and particles shape. The porous PAM silver nanoparticle hydrogels demonstrated excellent antimicrobial activity with significant effect against Escherichia coli, Micrococcus, and Candida albicus. Hence, it was clear that the developed hydrogels can be used effectively for preventing and treating infections.Item Development of green dual polymers for antibacterial applications(Taylor and Francis Online, 2015-11-03) Nayuniagri, Mithil Kumar; Kanny, KrishnanIn this article, we report on the antibacterial properties of a novel antimicrobial poly(citric acid-co-curcumin) polymer system that was prepared by a catalyst–free polyesterification process. The dual polymer of poly(citric acid-co-curcumin) was synthesized by varying the weight ratio of citric acid and curcumin monomers. Details of the synthesis, spectral (Fourier transform infrared, ultraviolet), thermal stability (Thermogravimetric analyses), and the morphological (Scanning electron microscopy/energy dispersive spectroscopy) characterization of dual polymers are presented in this scientific article. The UV–visible spectrometry was used to confirm the copolymerization of curcumin dispersion in the dual polymer systems. The presence of functional groups of copolymers was confirmed by Fourier transform infrared spectroscopy. The thermogravimetric analysis results indicated that poly(citric acid-co-curcumin) have a thermal stability up to 225°C. The ratios used were 1:0.25, 1:0.5, 1:0.75, and 1:1 and their antibacterial properties were studied with respect to their activity on gram-positive and gram-negative bacteria. This dual polymer was inoculated onto a Petri dish and its ability to inhibit the growth of Escherichia coli, Staphylococcus, Bacillus subtilis, Candida albicans (fungus), and Micrococcus luteus was evaluated using the bacterial disc method. Results indicated inhibition properties to increase with increasing curcumin content and the dual polymer with highest curcumin content showed excellent antimicrobial activities against both gram-negative and gram-positive microorganisms. Hence, it was clear that the developed dual polymers may be effectively used for antibacterial applications such as wound dressing.Item A review on research and development of green composites from plant protein-based polymers(Wiley Online Library, 2015-07-29) Jagadeesh, Dani; Kanny, Krishnan; Prashantha, K.Depletion of petroleum resources, together with increasing environmental concerns, calls for new solutions for many of our needs such as fuels, heating, materials, technical oils, and so on. Because of the ubiquitous use of petroleum-based products in their persistence in the environment and their fossil-fuel derived, alternatives to these traditional plastics are being explored. Totally, “green” biomaterials are of extra interest. Thus, strong composites containing both “green fibers” from plants and “green/biopolymers” from plants would be an ideal solution and they represent an emerging area in polymer science. Introduction and production of these composites into the material market would be important for environmental sustainability as their use can decrease the volume of petroleum-derived plastic waste dumps. This article reviews the current research efforts, techniques of production, trends, challenges, and prospects in the field of green composites from protein-based polymers. Green composites are comparatively cheap and abundant, but further research and development is needed for a broader utilization. POLYM. COMPOS., 2015. © 2015 Society of Plastics EngineersItem Bulk cure study of nanoclay filled epoxy glass fiber reinforced composite material(De Guyter, 2016) Olusanya, John; Kanny, Krishnan; Singh, ShaliniThe correlation between cure properties and structure of nanoclay filled composite laminate has not been studied extensively. Most of the cure studies were preferably done using small samples through a calorimetric method. In this study, the effect of varying weight ratio of nanoclay (1–5 wt%) on bulk cure properties of epoxy glass fiber reinforced composite (GFRC) laminates was studied. Bulk cure of unfilled and clay filled GFRC laminates was determined using the dynamic mechanical analysis-reheat method (DMA-RM). DMA-RM cure properties gave a better coordinate method, with better cure efficiency achieved in clay filled GFRC laminates when compared to unfilled GFRC laminates. The correlation between nanoclay and DMA-RM degree of cure was coordinated with compressive and in-plane shear strength properties. The degree of cure value of 78% by DMA-RM at 1 wt% clay filled GFRC corresponds with the compressive modulus and in-plane shear strength highest values, which are 20% and 14% increase, respectively, also at 1 wt% clay filled GFRC. The structures of the unfilled and clay filled epoxy were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Clay filled epoxy up to 3 wt% showed no distinct diffraction peak, which suggested that nanoclay is randomly dispersed in the matrix.Item Reuse of cured epoxy as a reinforcement in an epoxy composite(Wiley, 2013) Mohan, T. P.; Kanny, KrishnanThis article discusses the reuse of a thermoset-based epoxy polymer. In this method, cured epoxy polymer is ground to powder of particle size ranging from 1 to 30 μm. The ground epoxy is then filled in an epoxy polymer to form an epoxy–epoxy composite system using both room and high temperature processing. The amount of filler material was varied from 1 to 10 wt% in the epoxy matrix. Rheology and tensile properties test were then performed. The result shows that the room temperature-processed epoxy composites (above 5 wt% of powders) resulted in the formation of voids, agglomeration of particles, and reduced degree of cure leading to a decrease in tensile properties. These drawbacks (voids, agglomeration, and low degree of cure) were correspondingly absent in composites processed at high temperature. Results from this work suggest that the thermoset polymer can be reused effectively with minimal changes to the unfilled resin properties. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics EngineersItem Melt blend studies of nanoclay-filled polypropylene (PP)–high- density polyethylene (HDPE) composites(Springer, 2013) Mohan, T. P.; Kanny, KrishnanThe objective of this work is to study how the rheological factors of unfilled and nanoclay-filled HDPE– PP blend series influence the structure, morphology, and mixing characteristics. For this study, a series of HDPE–PP blends (0–100 wt % HDPE), with and without nanoclay, was prepared by using melt-mixing method. Nanoclay was varied from 0 to 5 wt % in all the blend and polymer series. The rheological properties were examined by melt viscosity, scanning electron microscopy, and theory of mixing. The result indicated that the viscosity of the blend increased as HDPE and nanoclay content increased, and also affected the structure and morphology of the resulting blend. The thermal properties were examined by using differential scanning calorimetry and suggest improved crystalline and melting characteristics of PP and PP-rich phase of blend. The structure of nanoclay-filled blend was examined by X-ray diffraction and transmission electron microscopy, confirming the formation of nanocomposite with improved tensile properties.Item Chemical treatment of sisal fiber using alkali and clay method(Elsevier, 2012-07-24) Mohan, T. P.; Kanny, KrishnanIn this study the chemical treatment of sisal fiber using the combined alkali (NaOH) and clay is discussed. The purpose of this fiber treatment is to improve the fiber–matrix compatibility, interface strength, mechanical, thermal and water barrier properties. The phase change due to chemical treatment of raw sisal fiber was examined by Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) methods. The result shows the presence of about 20 wt.% clays in NaOH–clay treated sisal fiber with 2.6 reduced water uptake and also with improved mechanical and thermal properties. Subsequently the treated and untreated fibers were reinforced in polypropylene (PP) matrix and the mechanical and thermal properties were examined. The result indicates that the fiber–matrix interface strength, adhesion, glass transition temperature and tensile properties of composites were improved in NaOH–clay treated fiber composites.