green-materials
Talks @ National Seminar on Green Materials
The Dept. of Chemistry, Bishop Moore College, Mavelikara is hosting some of the finest researchers in the material science field in India from 27th Feb to 1st Mar 2013. Here's a peek at what they would talk about.
This page features a daily feed of abstracts of all upcoming presentations. Visit daily for more. All content on the domain green-materials.in is copyrighted and should not be copied or used without permission.
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Rheological and surface parameters governing the adhesion of food gels on solid surfaces
The adhesion of food on solid surfaces, industrial plants and packaging, is reported to be associated with mechanical anchoring and/or from interfacial strengths [1, 2]. The level of adhesion evolves not only according to the properties of surfaces of both materials in contact, but also according to the composition, structure and to the rheological properties of the food. The surface properties of food and packaging, such as surface topography or solid surface tension, should be taken into account for evaluating the adhesion [3-4]. According to the thermodynamic theory, the work of adhesion (WA) refers to the surface energy (g) difference between the adhesive (s) and the adherent (l) surfaces in contact following the equation WA = gs + gl − gsl
The fracture energy is related to thermodynamic work of adhesion [5] as:
W = WA (1+ f (t, ν)) (1)
where f (t, ν) is a temperature and rate-dependent viscoelastic term.
This work was carried out to determine the dominating factors in the phenomena of adhesion to the solid surface using representative model systems of the food made with biopolymers. The adhesiveness of iota–carrageenan gels was evaluated based on their rheological properties: not only viscoelastic (storage modulus and loss tangent), but also properties at large deformation like breaking shear stress and breaking shear strain. The thermodynamic properties on adhesion was studied by using different solid surfaces in contact (steel, glass and plastics) or gel added with milk proteins such as sodium caseinate or whey protein isolate, for which the viscoelastic properties did not change.
In our models, the adhesiveness increased at higher concentrations of carrageenan and also with increased amounts of caseinate (but not a high rise with added WPI). This was understood to be a consequence of large deformation rheological properties (breaking shear stress, sb) of the gels rather than their small deformation properties (storage modulus, G’). But for gels possessing similar breaking shear stress values, gels containing added caseinate exhibited higher adhesiveness when compared to those containing whey proteins, suggesting dissimilar surface properties of proteins. When in contact with different surfaces, adhesiveness for gel containing carrageenan alone seemed to increase with increasing hydrophilicity of solid surface. In presence of added proteins, no relation was evidenced between adhesion and surface properties suggesting different interactions of proteins with different surfaces.
[1]. M.-C. Michalski, S. Desobry, J. Hardy, Crit. Rev. Food Sci. Nutr. 37 (1997) 591.
[2]. S.M. Fiszman, M.H. Damasio, J. Text. Stud. 31 (2000) 69.
[3]. V. Bosc, I. Ferrari, C. Michon, Colloids and Surfaces A: Physicochem.Eng.Aspects, 331 (2008) 2
[4]. J.H. Clint, Curr. Opin. Colloids Interface Sci. 6 (2001) 28.
[5]. D.E. Packham, Int. J. Adhesion Adhesives 23 (2003) 437.
Rubie Mavelil Sam, Véronique Bosc, Camille Michon
AgroParisTech, UMR 1145 Ingénerie Procédés Aliments, 1 Avenue des Olympiades, F-91300, Massy, Paris, France
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NATURAL RUBBER BASED NANOCOMPOSITES
Polymeric nanocomposites have drawn great attention in recent years due to its versatile applications. This is due to the wonderful improvement in its overall properties by the incorporation of nanofillers. The large surface area of nanofillers is available for wetting by the polymer and therefore there are enormous interfaces between the two intermixed phases compared to usual microcomposites. Natural rubber was also reinforced with several nanoaparticles for its improvement in properties. In this review, the effects of nanoclay and carbon nanotubes on the various properties of NR nanocomposites were discussed.
Natural rubber –clay nanocomposites were prepared by mixing NR with organo-modified monmorillonite nanoclay. The intercalation of polymer chains between the alumino silicate layers and morphological studies of the composites were analyzed by X-ray diffraction studies. X-ray diffraction results indicated intercalation of NR into silicate interlayers followed by exfoliation of the silicate layers into the silicate matrices. The effect of type of modified clay, concentration of the clay and vulcanizing systems on the mechanical and transport properties of the composites were studied in detail. The liquid and vapour transport through composites were reduced very much compared with neat polymers.
Multiwalled carbon nanotube (MWCNT) reinforced natural rubber (NR) composites were prepared by melt blending method as a function of CNT loading. Nanocomposites were characterized by Transmission electron microscopy and Raman spectroscopy method. Mechanical and transport properties of the nanocomposites were extensively studied. There is an overall improvement in the mechanical and thermal stability of the composites prepared.
Soney C.George
Center for Nanoscience and Technology, Amal Jyothi College of Engineering, Koovapally P.O, Kottayam 686518, Kerala, India
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Green nanocomposites from agricultural resources: Preparation and its various characterisations
Cellulose nanofibrils (BNF) isolated from banana bast fibre by steam explosion process were used as reinforcement (filler) for poly-L-lactic acid (PLLA) matrix with the goal of making sustainable novel ‘green nanocomposites’. The BNF were pretreated with two different surfactants in order to find a system that would give maximum compatibility between matrix and filler. Amino propyl triethoxy silane (APTES) and a naturally extracted surfactant, saponin, were the used surfactants. The procedure to attain uniform dispersion and maximum reinforcement of BNF in PLLA matrix was assessed, and the spectroscopic, mechanical, thermal and biodegradation properties of the compression molded nanocomposites were analysed. Saponin modified nanocomposites were found to exhibit superior mechanical properties compared to its untreated counterpart and it is a competent candidate for silane treated nanocomposites. All the studied nanocomposites were found to be completely biodegradable but the rate of degradation was higher in untreated nanocomposites.
Eldho Abraham, Laly A Pothan, Sabu Thomas
1 Department of Chemistry, Bishop Moore College, Mavelikkara,
Kerala, India 690 101
2 School of Chemical Sciences, Mahatma Gandhi university, Kottayam,
Kerala, India 686 560
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Environment-friendly Design of High Performance Materials
The wide ranges of requirements for novel materials have by now created a great deal of curiosity among scientists in various areas of research. Much attention is now being given to the recent developments related to environment friendly, high performance materials, which include a number of homogeneous and heterogeneous systems. The target of many of the above mentioned research programmes is to design, fabricate and characterize materials which include multifunctional matrices, reinforcements , membranes, appliances for physical medicine etc. These materials can function efficiently in complex and demanding conditions . They find applications in aerospace, automotive, construction, offshore, chemical, electronic and electrical industries.The strategies being followed have the potential to provide us with a better environment, can help us to understand and control emissions, and inspire to adhere to green technologies.
The present topic focuses on the efforts from the speaker’s group to develop and optimize novel systems modified by suitable partners or by using impressive compatibilisation strategies. The experience to interface the findings with industries shall be highlighted. Special attention shall be given to green composite systems. The fabrication of hybrid systems shall also be discussed.
The paper initially discusses the basic requirements for the functioning of high performance systems fracture visco-elasticity, quasi-crystalline state etc. are highlighted. Strategies for composite strengthening while reducing density are included.in an environment friendly way. The basic functional features related to yield,
Typical systems identified are hierarchical zeolites, elastomers, natural fibres,nano-crystalline cellulose, membrane materials, lubricants etc.
Unnikrishnan Gopalakrishna Panicker
National Institute of Technology Calicut, Kerala, India
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Reactive Graft Copolymers of Cellulose and Chitosan with Functional Ligands for Use as ‘Globe-Compatible Materials’ in the Field of Analytical, Environmental and Biomedical Applications
Natural materials available in large quantities from agricultural residues are suitable for the removal and recovery of various organic and inorganic moieties from aqueous solutions because of their low cost, biodegradability, presence of different functional groups, sludge form and availability. Cellulose is one among them, which has numerous applications for the removal of heavy metals, recovery of proteins and potential drug delivery vehicles. In the present work, cellulose was extracted from agricultural residues and surface modifications such as grafting and cross-linking followed were carried out to increase its hydrophilicity, elasticity, water sorbency, adsorption or ion exchange capability and thermal resistance. Grafted celluloses were functionalized and were used as the adsorbent/ion exchange materials for the removal and recovery of various organic and inorganic moieties from aqueous solutions in the field of separation science attention due to their high strength and stiffness combined with low weight, high surface area, unique mechanical properties, biodegradability, hydrophilicity, and renewability. Nanocellulose based novel hydrogels were also prepared by graft copolymerization technique and used for the selective separation of proteins from aqueous solutions. nanocomposites with interpenetrating polymer net works bearing different functional moieties were also fabricated for the selective separation proteins for biomedical applications.Chitosan is a linear polysaccharide obtained by extensive deacetylation of chitin, which is the most abundant polysaccharide in nature after cellulose. Despite its all advantages including high mechanical strength, hydrophilicity, good adhesion, nontoxicity, biodegradability, and biocompatibility, chitosan lacks good solubility at physiological pH so that it is unsuitable for ionic absorption in neutral and physiological environments. Hydrophilic properties of the chitosan have been improved by different modifications. Novel pH sensitive composite bydrogels were prepared by in-situ intercalation olymerization between hydrophilic monomers, containing both nonionic and anionic groups, and chitosan derivatives intercalated clays, and were well characterized and used as pH responsive drug delivery systems.and water treatment applications. Nanocellulose have gained increasing Polymer-grafted-cellulose/clay.
T. S. Anirudhan
Department of Chemistry, University of Kerala, Kariavattom,
Trivandrum 695 581
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Reducing the intake of medicine by targeted sustained delivery of drugs via smartgels
Its high time that we concerned about an ever increasing pollution: Drug Pollution-The millions of doses of drugs that we swallow annually to combat cancer, pain,depression and other ailments do not disappear harmlessly into our digestive systems, but instead make their way back into the environment where they may contaminate drinking water and pose a threat to aquatic wildlife. With this in mind, we tried to determine how efficiently a biocompatible pH sensitive gel synthesized can reduce the overdose and help the nature’s self-cleansing processes and thus eliminating these man-made pollutants. Being able to reduce the overdose of drugs is important because many medicines consumed are not rendered biologically harmless when they pass through the body. Conventional sewage treatment systems may not remove them, and unused drugs may be flushed down the toilet or thrown into the trash, ultimately ending up in groundwater or surface water, where they may affect aquatic life and drinking water quality. Hydro gel films of gelatin with sodium alginate in SDS micelle were prepared. They demonstrated excellent pH sensitivity and were selected for the study of release profiles of a model drug, Ciprofloxacin hydrochloride. The films were characterized by FTIR, XRD, SEM analysis and biological studies (in vivo and in vitro analysis) to assess their toxicity.
Dr Jinu George
P G and Research Department of Chemistry, Sacred Heart College, Thevara, Kochi, INDIA 682013
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SYNTHESIS OF NANOSIZED CALCIUM CARBONATE AND ITS INFLUENCE ON MECHANICAL PROPERTIES OF NR/EPDM BLENDS
Abstract
The polymer mediated technique is a versatile technique for the preparation of nano particles In the present study we have prepared the nano particles of calcium carbonate by polymer mediated growth method and were characterized using different techniques (Mishra S, Patil U D and Shimpi N G, 2009). Further, these particles were incorporated into NR/EPDM blends by two roller mill mixing technique. Various mechanical properties of the composites were characterized by standard methods. Nano particles of calcium carbonate in the range of 5-10 nm were prepared and characterized by XRD and TEM. The tensile testing results showed that the presence of nanoCaCO3 enhances the mechanical properties of NR/EPDM blends.
P G Prajith, K Kurien Thomas and T Muraleedharan Nair
1. Research Department of Chemistry, Bishop Moore College,
Mavelikara-690110,
Alappuzha, Kerala, India
2. Common Facility Service Centre, Department of Industries and
Commerce Payyanad, Manjeri, Kerala, India
3. Department of Chemistry, Bishop Moore College,
Mavelikara-690110,
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Starch – A potential thermoplastic biopolymer
Natural polymers, such as starch and cellulose have the potential to replace many current polymers if new material composites can be prepared to rival the performance of existing composites. While the conventional composites offer excellent mechanical properties and durability, most of them are derived from petroleum feed stock. Utilisation of biodegradable materials has become necessary in order to maintain global environmental and ecological balance. From a technical point of view the study has shown, these bio-based composites will enhance mechanical strength and acoustic performance, reduce material weight and fuel consumption, lower production cost, improve passenger safety and shatterproof performance under extreme temperature changes, and improve biodegradability for the auto interior parts. The rising concern towards environmental issues and, on the other hand, the need for more versatile polymer-based materials has led to increasing interest about polymer composites filled with natural-organic fillers, i.e. fillers coming from renewable sources and biodegradable. The composites usually referred to as “green”, can find several industrial applications. Efforts are employed to improve bio-polymer and more competitive. Global warming, the growing awareness of environmental and waste management issues, dwindling fossil resources, and rising oil prices: these are some of the reasons why “bio”products are increasingly being promoted for sustainable development. “Bio”products, such as starchy and cellulosic polymers, have been used for thousands of years for food, furniture and clothing. But it is only in the past two decades that “bio”products have experienced a renaissance, with substantial commercial production. Recent technological breakthroughs have substantially improved the properties of some bio-based polymers, such as heat resistant polylactic acid, enabling a wider range of applications. An increasing number of applications have emerged recently (including packaging, biomedical products, textiles, agriculture, household use and building) where biodegradable polymers and biocomposites are particularly suitable as sustainable alternatives. Composites are very useful in replacing some of the petroleum based composites in use today and reducing the amount of plastics in the landfills. These products find applications in ceilings, partition, doors, rims, panels, aircraft, ships, etc. Green composites are essential since it promote agricultural growth, give eco-friendly products, conserve the nature and bringing opening for new market.
M. S. Sreekala
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MORE CHEMISTRY
Among the new strategies for organic synthesis, microwave irradiation is important as it induces specific interaction between materials and waves of electromagnetic nature assimilated to dielectric heating. Due to interaction between materials and electromagnetic waves, heat is generated in the core of the materials without superficial overheating with highly homogeneous temperature. A rapid, clean and environmentally friendlier approach for organic synthesis and transformation using microwave irradiations with and without the presence of organic solvents is of great importance in green chemistry.
Even though chemistry played an important role in the improvement of modern life on earth with the invention of dyes, drugs, insecticides, pesticides, fertilizers, plastic, fiber etc., it earned the discredit and hatred of man due to the pollutants it added to air, water and soil. With the increasing awareness of environmental pollution and hazards, it has become a challenge for chemists to design newer or alternative ways of safe and clean chemical transformations. Appropriate chemical manufacturing processes should be developed to minimize damage to the ecosystem. The evolution of GREEN CHEMISTRY is the answer to all these problems which are described as twelve principles by John Warnar and Paul Anastas as follows: 1. Prevention of waste, 2. Atom economy, 3. Synthesis of less hazardous chemicals, 4. Designing of safer chemicals for use, 5. Use of safer solvents and auxiliaries, 6. Design of energy efficiency, 7. Use of renewable feedstock, 8. Reduction of unnecessary derivatives, 9. Use of catalytic reagents, 10. Design of environment friendly and easily degradable products, 11. Real time analysis of pollution and prevention, 12. Inherently safer chemistry for accident prevention.
In the past few years, microwave heating has been found to be convenient source of energy not only in kitchen but also in chemical laboratories. Many of the basic principles of green chemistry are best suited for microwave induced chemical reactions in Laboratories. The microwave induced organic reaction enhancement (MORE) chemistry has emerged as a significant non-conventional method of reaction activation. It is simple, safe, fast, eco-friendly, economic and efficient method of synthesis. Either traditional microwave oven or a computerized version of commercial one with ability for rapid determination of thermodynamic function of chemical reactions can be used. The application includes catalytic hydrogenesis of alkenes, hydro cracking of bitumen obtained from tar, degradation of polychlorinated hydrocarbons, waste material management, polymer and ceramic technology. The other applications of MORE chemistry involve sterilization of pharmaceutical preparations, thermo therapy, rapid dissolution of compounds, radio pharmaceutical compounding, drying of medicinal plants, extraction of essential oil from medicinal plants, inactivation of enzymes in food products, hydrolysis of proteins and peptides, activation of chromatographic adsorbents, lipid analysis, etc. It is an excellent tool for the synthesis and purification of organic compounds on small and large scale.
Dr. K. Kurien Thomas
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Preparation and Characterization of Electrospun PLA-Chitosan Nanofibres
Chitin is the second most abundant natural amino polysaccharide, made up of β-(1→4) linked 2-acetamido 2-deoxy β- D-glucose.Chitosan, the deacetylated derivative of chitin possesses exceptional chemical and biological qualities that can be used in a wide variety of industrial and medical applications. In this work chitosan as well as polylactic acid, abiodegradable polymer were successfully electrospun by varying the concentration as well as voltage.The SEM chracterization of the electrospun samples were done. From the SEM analysis the optimum concentration and the voltage were determined. PLA-chitosan composites having different chitosan ratio were also prepared via elecctrospinning.SEM, FTIR and XRD characterization were done.
Merin Sara Thomas1a, 2a, Nanadakumar K1b , Sabu Thomas1c, Laly A. Pothen2b
1Centre for Nanoscience and Nanotechnology, M.G. University,Kottayam,Kerala, India
2 Bishop Moore College, Mavelikara,Alappuzha, Kerala, India.
#Chitosan#Electrospinning#SEM#Polylactic acid#green materials#greenmtls#www.green-materials.in#lalypothan
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Effect of Organically Modified Nanoclay on the Morphological, Rheological and Mechanical Behavior in Chlorobutyl Rubber Nanocomposites.
The intercalation/exfoliation of organically modified montmorillonite (OMMT) nanoclay in chlorobutyl rubber (CIIR) has been investigated. The samples were prepared by mechanical mixing technique using two roll mill. X-ray diffraction has been used to evaluate the formation of nanoscale dispersion of clay in the hybrid composites and the localization of the polymers between the organosilicate layers. The effect of incorporation of organically modified clay on morphological and rheological properties has been studied.
Ajesh K.Zachariah1, Arupkumar Chandra2, P.K.Mohammed2, Sabu Thomas1*
1School of Chemical Sciences, Mahatma Gandhi University, Priyadarsini Hills, Kottayam, Kerala, India.
2Apollo Tyres,Vadodhara,Gujarat,India
#CIIR nanocomposites#non-linear viscoelasticity#mechanical property#morphology#bishop moore college#green materials#greenmtls#www.green-materials.in#Sabu Thomas
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Greening the Chemistry Curriculum
Green chemistry represents the pillars that hold up our sustainable future. It is imperative to teach the value of green chemistry to tomorrow's chemists. It is clear that many industries and the research of many academics recognize the significance of green chemistry. However, very little discussion of green chemistry has found its way into the chemistry curriculum. We have to recognize the need to make a concerted and sustained effort to green the curriculum so that future chemists are taught to “think green.” We have to develop materials that will aid in the infusion of green chemistry into the curriculum such as green chemistry laboratory experiments, real-world cases in green chemistry and short courses on green chemistry.This lecture will highlight the aspects of “Greening the Curriculum” in all branches of chemistry (Organic, inorganic, environmental & industrial ).
S.Chandrasekaran
Department of Organic Chemistry
Indian Institute of Science , Bangalore
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Transport of Aromatic and Aliphatic Solvents through Natural Rubber/Nitrile Rubber Blend Nanocomposite membranes.
The permeability of some hazardous organic solvents through polymer blend nanocomposites membrane was studied to elucidate the transport mechanism. The sorption and diffusion characteristics of Natural rubber (NR) and acrylonitrile butadiene rubber (NBR) blends loaded with nanoclay- Cloisite 10 A have been investigated. The penetrants used were hexane, toluene and xylene. The effect of blend ratio, solvent size and filler loading on the diffusion of aromatic solvents and aliphatic solvents through NR/NBR blend systems are reported. Filled samples have been found to show a reduced solvent uptake compared to the unfilled sample for the entire blend ratio. This can be attributed to the better filler reinforcement by the nanofiller. Blends with higher NBR content exhibited the lowest solvent uptake which has been attributed to the higher cohesive energy density of NBR. The unfilled and filled systems was found to exhibit anomalous behaviour. The effect of fillers on other diffusion parameters like sorption coefficient solvent uptake, diffusion, sorption and permeation constants also were verified and was found to be depend on blend composition and clay loading. The observations have been correlated with the morphology of the systems. The diffusion data was applied to mathematical models to predict the diffusion behaviour through polymers, to optimize the diffusion kinetics and elucidate the physical mechanism of transport. Here the first order kinetic equation, Higuchi model, Korsmeyer Peppas model and Peppas-Sahlin equation were used to predict the diffusion behaviour.
Hanna .J.M1, N. Lyczko2 A. Nzihou 2, K.Joseph 3 C. Mathew 4, S. C. George 5, S. Thomas1, *
1School of Chemical Sciences, Mahatma Gandhi University,India, 2Université de Toulouse ; Mines Albi ; France, 3Indian Institute of Space Science and Technology, India,4Dept of Chemistry, S. B. College, India, 5Amal Jyothi College of Engineering,India.
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POLYMER BASED GREEN MATERIALS
Polymers have established themselves as an important class of engineering materials along with metals and ceramics. When the consumption of polymers is on the rise, questions about their environmental impact also become relevant. One of the major criticisms against polymers is that they lead to depletion of nonrenewable energy sources since petroleum is the major raw material source for synthetic polymers. Polymer waste management techniques such as incineration, land filling etc. also impact the environment in one way or other. For a country like India, the best option for polymer waste management is improving the quality and quantity of polymer recycling. One of the major difficulties in recycling is the large quantity of additives used in all polymer formulations. Recycling can be easily performed to achieve better quality products by reducing the amount of additives in polymer formulations. Another technique for easy recycling is to make the additives also recyclable. Two techniques are described in this paper for developing recyclable polymer composites.
1. Development of polymer nanocomposites
Nanofillers have emerged as the ultimate reinforcement for polymers. The major advantage with nanofillers is that they need be added only in very small quantities compared to conventional fillers. This makes the product easily recyclable.
2. Development of composites based on polymer matrix and polymer fiber
Composites are developed by reinforcing polymer matrix with polymer fibres. This makes the both the matrix and reinforcement recyclable.
Dr.K.E.George
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Fluorescent enhancement of europium complex when codoped with terbium in polymer matrices
Complex molecules, especially lanthanide complexes can be doped into suitable host matrices to provide practical applications for the fluorescence phenomenon and to improve the thermal and mechanical properties of the resultant composites, including the processability aspects. Europium-β-diketone chelate doped poly (methyl methacrylate) and poly (methyl methacrylate)/poly (ethylene co-vinyl acetate) blends have been successfully prepared and characterized. The fluorescent enhancement of the europium complex in matrix when codoped with terbium complex has been studied. The structural properties of the complex doped systems have been studied by Infrared spectroscopy. The crystalline state of the complex has been studied using fluorescence spectroscopy. The fluorescence life time of the complex doped polymeric system has been studied using time resolved fluorescence spectrometer. The complex doped PMMA/EVA polymer network developed is considered to be a potential candidate for the development of optoelectronic devices those possess superior mechanical properties.
Corresponding author: G. Unnikrishnan, E mail: [email protected],
R. Puthiyottil1*, S. Varghese2, U. Gopalakrishnapanicker1, J.T. Guthrie3
1Department of Chemistry, National Institute of Technology Calicut, India 673601
2School of Nano science and Technology, National Institute of Technology Calicut, India 673601
3 Department of Color Science, School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK
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PREPARATION, PHYSIO–CHEMICAL CHARACTERISATION AND METAL ADSORPTION STUDIES OF CALCIUM ALGINATE BEADS
Sodium alginate, a water soluble linear hetero polysaccharide consists of 1,4 linked - D-mannuronic acid(M) and -L-guluronic acid (G) monomers .Divalent(Ca2+,Mg2+) and other polyvalent cations (Fe3+ ,Mn3+)induce instant cross linking with the carboxylate group of alginate forming insoluble and thermally stable hydrogels.Calcium ions react with the alginate molecule at G block regions forming a junction zone known as egg- box arrangement. These hydrogels extensively swell in the presence of an aqueous medium and hence has a wide range of applications in biomedical and pharmaceutical field as drug delivery systems.Alginates,derived from seaweeds are found to be one among the effective low cost adsorbents for removing heavy metals from dilute solutions.The present work addresses the physico chemical characterization and metal adsorption characteristics of calcium alginate beads.
P.GEETHA1and M.S. LATHA2
1Department of Chemistry, Bishop Moore college, Mavelikara,Kerala,India
2 Department of Chemistry, S. N. College, Chengannur, Kerala, India
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Bio Inspired Micro and Nanocomposites for the Future
Micro and nano bio inspired composite materials are the best future materials for the coming millennium. Cellulose fibers, chitin and starch in different length scales offer out standing properties like stiffness, toughness and other mechanical properties. Composites from polymers (rubbers and plastics) and reinforcing fibers provide best properties of each. They replace conventional materials in many structural and non-structural applications. Both natural fibers and polymers are light, on combination they give composites of very high strength to weight ratio. In recent years composites made from natural (cellulosic) fibers and organic polymers have gained a lot of interest in construction and automobile industry. Unlike synthetic fibers, natural fibers are abundant, renewable, cheap and of low density. Composites made from natural fibers are cost effective and environment friendly. However, lack of interfacial adhesion and poor resistance to moisture absorption makes the use of natural fibers less attractive for critical applications. However, these problems can be successfully alleviated by suitable chemical treatments. This presentation deals with the use of natural fibers such as pineapple leaf fiber, coir fiber, sisal fiber, oil palm fiber and banana fiber as reinforcing material for various thermoplastics, thermosets and rubbers. The fiber surface modifications via various chemical treatments to improve the fiber-matrix interface adhesion on mechanical, viscoelastic, dielectric rheological ageing and thermal properties will also be discussed. Experimental results will be compared with theoretical predications. The advantages of hybridizing natural and glass fibers also will be scanned briefly. The use of these composites as building materials will be discussed. Finally recent developments in cellulose nanocomposites, chtin nanocomposites and starch nanocomposites will also be presented.
Sabu Thomas, Centre for Nanoscience and Nanotechnology
Mahatma Gandhi University Kottayam, Kerala, India - 686 560
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