| 1. |
- Baby, Thomas, et al.
(författare)
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A new approach for the shaping up of very fine and beadless UV light absorbing polycarbonate fibers by electrospinning
- 2019
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Ingår i: Polymer testing. - : Elsevier. - 0142-9418 .- 1873-2348. ; 80
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Tidskriftsartikel (refereegranskat)abstract
- An innovation will be recognized as successful only if it satisfies all phases of product development; i.e. from the specification to mass production. Therefore, a cost-effective production by keeping the best possible characteristics is vital in any Industry. Large scale production of polymer fibers with ultrafine morphology is such a challenge to in the field of nanotechnology. The idea proposed here utilizes the versatile electrospinning technology for the preparation of uniform, beadless and ultraviolet light absorbing polycarbonate (PC) nanofibers. The average diameter limits to 114 nm and that too by using most convenient and comparatively less toxic solvent mixture. This method is simple and so far, it is not reported elsewhere. For THF-DMF system a PC concentration of 17 w/v% and for DCM-DMF system a PC concentration of 15 w/v% was found to be the optimum polymer concentration. The average fiber diameter and bead density were very much influenced by the viscosity, conductivity and concentration of the solution used for electrospinning. The PC fibers (PC concentration of 15 w/v % in DCM-DMF system) with lowest average diameter of 114 nm shows excellent ultraviolet absorption, semicrystalline nature, enhanced glass transition temperature and thermal stability.
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| 2. |
- Das, Oisik, et al.
(författare)
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Flammability and mechanical properties of biochars made in different pyrolysis reactors
- 2021
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Ingår i: Biomass and Bioenergy. - : Elsevier. - 0961-9534 .- 1873-2909. ; 152
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Tidskriftsartikel (refereegranskat)abstract
- The effect of pyrolysis reactors on the properties of biochars (with a focus on flammability and mechanical characteristics) were investigated by keeping factors such as feedstock, carbonisation temperature, heating rate and residence time constant. The reactors employed were hydrothermal, fixed-bed batch vertical and fixed-bed batch horizontal-tube reactors. The vertical and tube reactors, at the same temperature, produced biochars having comparable elemental carbon content, surface functionalities, thermal degradation pattern and peak heat release rates. The hydrothermal reactor, although, a low-temperature process, produced biochar with high fire resistance because the formed tarry volatiles sealed water inside the pores, which hindered combustion. However, the biochar from hydrothermal reactor had the lowest nanoindentation properties whereas the tube reactor-produced biochar at 300 °C had the highest nanoindentation-hardness (290 Megapascal) and modulus (ca. 4 Gigapascal) amongst the other tested samples. Based on the inherent flammability and mechanical properties of biochars, polymeric composites’ properties can be predicted that can include them as constituents.
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| 3. |
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Fiber Reinforced Composites : Constituents, Compatibility, Perspectives, and Applications
- 2021
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Samlingsverk (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- Polymer-based fibre-reinforced composites FRC’s have now come out as a major class of structural materials being used or regarded as substituent’s for metals in several critical components in space, automotive and other industries (marine, and sports goods) owing to their low density, strength-weight ratio, and fatigue strength. FRC’s have several commercial as well as industrial applications ranging from aircraft, space, automotive, sporting goods, marine, and infrastructure. The above-mentioned applications of FRC’s clearly reveal that FRC’s have the potential to be used in a broad range of different engineering fields with the added advantages of low density, and resistance to corrosion compared to conventional metallic and ceramic composites. However, for scientists/researchers/R&D’s to fabricate FRC’s with such potential there should be careful and precise design followed by suitable process development based on properties like mechanical, physical, and thermal that are unique to each application. Hence the last few decades have witnessed considerable research on fibre reinforced composites. Fibre Reinforced Composites: Constituents, Compatibility, Perspectives and Applications presents a widespread all-inclusive review on fibre-reinforced composites ranging from the different types of processing techniques to chemical modification of the fibre surface to enhance the interfacial adhesion between the matrix and fibre and the structure-property relationship. It illustrates how high value composites can be produced by efficient and sustainable processing methods by selecting different constituents [fibres and resins]. Researchers in academia working in composites and accompanying areas [materials characterisation] and industrial manufacturers who need information on composite constituents and how they relate to each other for a certain application will find the book extremely useful when they need to make decisions about materials selection for their products.
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| 4. |
- George, Gejo, et al.
(författare)
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Thermal, calorimetric and crystallisation behaviour of polypropylene/jute yarn bio-composites fabricated by commingling technique
- 2013
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Ingår i: Composites. Part A, Applied science and manufacturing. - : Pergamon. - 1359-835X .- 1878-5840. ; 48, s. 110-120
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Tidskriftsartikel (refereegranskat)abstract
- Commingled biocomposites based on polypropylene/jute yarns were prepared using commingling technique. The thermal and calorimetric behaviour of these commingled composites were studied with respect to fibre content and various chemical treatments. The thermal stability of the composites was found to be in between that of jute fibre and neat polypropylene (PP). Different chemical treatments increased the thermal stability of the composites due to increased interfacial adhesion between the matrix and reinforcement. Jute yarn acts as nucleating agents and favours the process of crystallisation thereby increasing the crystallisation temperature. Chemical treatments further increased the crystallisation temperature as a result of better interfacial adhesion between jute yarn and PP matrix. The close proximity of jute yarns weakens the mechanical bonds between PP molecules resulting in marginal lowering of melting temperatures. Polarized optical microscopic studies revealed the formation of transcrystalline layer around the jute fibre after 6 h.
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| 5. |
- George, Gejo, et al.
(författare)
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Viscoelastic behaviour of novel commingled biocomposites based on polypropylene/jute yarns
- 2012
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Ingår i: Composites. Part A, Applied science and manufacturing. - : Science Direct. - 1359-835X .- 1878-5840. ; 43:6, s. 893-902
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Tidskriftsartikel (refereegranskat)abstract
- Jute yarn reinforced polypropylene commingled composites were prepared by an environmentally benign technique called commingling method in which the matrix fibres and reinforcing fibres are intermingled together with good alignment. The dynamic mechanical properties or viscoelastic behaviour of these commingled composites were studied with reference to fibre content and various chemical treatments. The storage and loss modulus increased with fibre content where as tan δ decreased. KMnO4 and MAPP treated composites showed much higher storage and loss modulus values at all temperatures compared to untreated one. The glass transition temperature showed a marginal increasing tendency with fibre content and chemical treatments. The surface treatment mechanisms were supported by FT-IR spectra and the increase in interfacial adhesion after chemical treatments were supported by SEM images. Theoretical modelling was used to predict the values of storage modulus and tan δ and was found to be comparable with that of experimentally obtained results.
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| 6. |
- Jayan, Jitha S., et al.
(författare)
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An introduction to fiber reinforced composite materials
- 2021
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Ingår i: Fiber Reinforced Composites. - : Elsevier. ; , s. 1-24
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The present century has witnessed composite materials to be the most promising and shrewd material for a variety of applications. Among them fiber (natural or synthetic) reinforced composites (FRCs) have gained significant interest owing to the high demand for lightweight materials with high strength for specific applications. The advantages of FRCs include high strength to weight ratio, high durability and stiffness, good damping behavior, flexural strength and most importantly good resistance to corrosion, wear, impact and fire (depending on the matrix and fiber reinforcement). The presence of such wide array of properties for FRCs have led to them being used extensively in a number of applications including mechanical, aerospace, automotive, marine, sports, biomedical, construction etc. The past decades have visualized exciting research in the area of FRC's which helped to unveil the properties of these exciting materials further and consign them in appropriate applications. These FRCs have shown outstanding performance in different fields of applications and hence have been promoted by researchers as promising alternatives to solitary metals and alloys. The global demand for fiber reinforced composites is expected to grow at a faster pace with the aerospace industry occupying the top position in the years to come. Major driving factors for the rising demand is none other than the high strength to weight ratio, corrosion resistance, energy absorption on impact, moisture and chemical resistance possessed by these materials. This chapter gives a general overview on the characteristics and processing of FRC's that are systematically outlined in this book.
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| 7. |
- Prakashan, V.P., et al.
(författare)
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Investigations on SPR induced Cu@Ag core shell doped SiO2-TiO2-ZrO2 fiber optic sensor for mercury detection
- 2020
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Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 507
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Tidskriftsartikel (refereegranskat)abstract
- An investigation on Surface Plasmon Resonance (SPR) based fiber optic sensor for mercury detection utilizing copper-silver core shell nanoparticles (Cu@Ag CNPs) was carried out. TEM analysis was used to confirm the formation and morphological characteristics of the CNPs, whereas EDS and AAS analysis were used to validate the successful formation of the core shell nanoparticles. Good selectivity and sensitivity towards mercury were established by means of UV-Vis absorption spectroscopy. SPR based fiber optic mercury sensor was fabricated using Cu@Ag CNPs as the sensing materials and the results clearly prove that the Cu@Ag CNPs can act as suitable candidates for the same.
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| 8. |
- Saritha, Appukuttan, et al.
(författare)
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Elastomer-based materials for EMI shielding applications
- 2020
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Ingår i: Materials for Potential EMI Shielding Applications. - : Elsevier. - 9780128175903 ; , s. 121-143
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Electromagnetic shielding is presently considered very crucial for various electrical systems owing to the creation of electromagnetic pollution instigated by the alarming usage of electronic gadgets working at diverse frequencies and power levels. Conventionally used electromagnetic interference (EMI) metallic shields lack flexibility and hence cannot be considered as the right candidates for certain applications. This problem requires immediate attention because it causes drastic effects on the lifetime and performance of electronic devices and has an adverse effect on human beings as well. Rubber-based composite materials are regarded as suitable candidates for the fabrication of electromagnetic shields due to their combined electrical conductivity, interesting mechanical, and dielectric properties, elasticity to cover curved structures, and weather resistance for outdoor applications. This chapter aims to discuss the various fillers as well as elastomers used in the fabrication of elastomeric composites used in the preparation of EMI shielding devices. Finally a discussion of elastomeric blends used for shielding purpose will also be added.
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| 9. |
- Shanmugam, Vigneshwaran, et al.
(författare)
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Circular economy in biocomposite development : State-of-the-art, challenges and emerging trends
- 2021
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Ingår i: Composites Part C: Open Access. - : Elsevier. - 2666-6820. ; 5
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Forskningsöversikt (refereegranskat)abstract
- Biocomposites being environmentally-friendly alternative to synthetic composites are gaining increasing demand for various applications. Hence, biocomposite development should be integrated within a circular economy (CE) model to ensure a sustainable production that is simultaneously innocuous towards the environment. This review presents an overview of the state-of-the-art technologies for the adoption of the CE concept in biocomposite development. The study outlined the properties, environmental and economic impacts of biocomposites. A critical review of the life-cycle assessment of biocomposite for evaluating greenhouse gas emissions and carbon footprints was conducted. In addition, the opportunities and challenges pertaining to the implementation of CE have been discussed in detail. Recycling and utilisation of bio-based constituents were identified as the critical factors in embracing CE. Therefore, the development of innovative recycling technologies and an enhanced use of novel biocomposite constituents could lead to a reduction in material waste and environmental footprints. This article is one of the first studies to review the circularity of biocomposites in detail that will stimulate further research in enhancing the sustainability of these polymeric materials.
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| 10. |
- Simon, Sanu Mathew, et al.
(författare)
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Morphological and thermal studies of mesoporous TiO2-ZrO2 and TiO2-ZrO2-polymer composites as potential self cleaning surface
- 2020
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Ingår i: Materials Today. - : Elsevier. - 2214-7853. ; 33:part 2, s. 1327-1332
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Tidskriftsartikel (refereegranskat)abstract
- Inorganic-organic composites have significant importance in various fields including self cleaning displays, photocatalysis, solar energy conversion etc. The synthesis of polymer capped inorganic frameworks consisting oxides of Ti and Zr had been accomplished in a straightforward cost effective method. In this work, TiO2-ZrO2-Pluronic F127 composites were synthesized using sol-gel process in the presence of chelating ligand diethanolamine, which acts as a reaction inhibitor for hydrolysis and condensation of Ti and Zr alkoxide. For comparative studies, TiO2-ZrO2 composite sample under the same atmospheric conditions were also prepared. The structural and thermal properties were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), water contact angle measurement (WCA) and thermogravimetric analysis (TGA-DTA). The textural parameters such as surface area, pore volume and pore diameter were analyzed using nitrogen sorption analysis. The water contact angle measurements have shown that the synthesized polymer-based composite material was superhydrophilic.
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| 11. |
- Thomas, Bony, et al.
(författare)
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Electrochemical Properties of Biobased Carbon Aerogels Decorated with Graphene Dots Synthesized from Biochar
- 2021
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Ingår i: ACS Applied Electronic Materials. - : American Chemical Society (ACS). - 2637-6113. ; 3:11, s. 4699-4710
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Tidskriftsartikel (refereegranskat)abstract
- Carbon aerogels prepared from low-cost renewable resources are promising electrode materials for future energy storage applications. However, their electrochemical properties must be significantly improved to match the commercially used high-carbon petroleum products. This paper presents a facile method for the green synthesis of carbon aerogels (CAs) from lignocellulosic materials and graphene dots (GDs) from commercially available biochar. The produced carbon aerogels exhibited a hierarchical porous structure, which facilitates energy storage by forming an electrical double-layer capacitance. Surprisingly, the electrochemical analyses of the GD-doped carbon aerogels revealed that in comparison to pristine carbon aerogels, the surface doping of GDs enhanced the electrochemical performance of carbon aerogels, which can be attributed to the combined effect from both double-layer capacitance and pseudocapacitance. Herein, we designed and demonstrated the efficacy of a supercapacitor device using our green carbon electrode as a sustainable option. These green carbon aerogels have opened a window for their practical use in designing sustainable energy storage devices.
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| 12. |
- Wilson, Runcy, et al.
(författare)
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An introduction to materials for potential EMI shielding applications : Status and future
- 2020
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Ingår i: Materials for Potential EMI Shielding Applications. - : Elsevier. - 9780128175903 ; , s. 1-8
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The ever-increasing use and technological advancement in the electronic industry has led to an unwanted product known as the electromagnetic interference (EMI), which can harm other electronic devices and even human beings. This has led to extensive research in the area of EMI shielding. The conventional EMI shields were mostly metallic in nature; however, they had several disadvantages such as high cost, chance of corrosion, heavy weight, etc. This has led to the research on new materials for EMI shielding, ranging from polymeric composites, conducting polymer-based materials, porous materials for EMI shields, biodegradable and bio-derived materials for EMI shields, high-temperature EMI shields, ceramic and cement-based EMI shields, EMI shields based on textile materials, etc. The present book describes EMI shielding starting from the basics and mechanism of EMI shielding, testing methods to determine EMI shielding efficiency of different types of materials used in the current scenario to different types of EMI shielding materials that are being used.
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