S. D. Ganesh, Vasantakumar K. Pai, M. Kariduraganavar, Madhu B. Jayanna
The present paper discusses the aspects of the synthesizing valeric acid based poly(ether sulfone)s with active carboxylic acid pendants (VALPSU) from solution polymerization technique via nucleophilic displacement polycondensation reaction among 4,4′-dichlorodiphenyl sulfone (DCDPS) and 4,4′-bis(4-hydroxyphenyl) valeric acid (BHPA). The conditions necessary to synthesize and purify the polymer were investigated in some detail. The synthesized poly(ether sulfone)s comprise sulfone and ether linkages in addition to reactive carboxylic acid functionality; these active carboxylic acid functional groups were exploited to hold the phenyl sulphonic acid and phenyl phosphonic acid pendants. The phenyl sulphonic acid pendants in VALPSU were easily constructed by altering active carboxylic acid moieties by sulfanilic acid using N,N′-dicyclohexylcarbodiimide (DCC) mediated mild synthetic route, whereas the latter one was built in two steps. Initially, polyphosphoric acid condensation with VALPSU by 4-bromoaniline and next straightforward palladium catalyzed synthetic route, in both of which acidic pendants are clenched by polymer backbone via amide linkage. Without impairing the primary polymeric backbone modified polymers were prepared by varying the stoichiometric ratios of respective combinations. All the polymers were physicochemically characterized and pressed into tablets; electrical contacts were established to study the dielectric properties. Finally, the influence of the acidic pendants on the dielectric properties was examined.
{"title":"Thermal and Dielectric Behavior Studies of Poly(Arylene Ether Sulfone)s with Sulfonated and Phosphonated Pendants","authors":"S. D. Ganesh, Vasantakumar K. Pai, M. Kariduraganavar, Madhu B. Jayanna","doi":"10.1155/2016/7271959","DOIUrl":"https://doi.org/10.1155/2016/7271959","url":null,"abstract":"The present paper discusses the aspects of the synthesizing valeric acid based poly(ether sulfone)s with active carboxylic acid pendants (VALPSU) from solution polymerization technique via nucleophilic displacement polycondensation reaction among 4,4′-dichlorodiphenyl sulfone (DCDPS) and 4,4′-bis(4-hydroxyphenyl) valeric acid (BHPA). The conditions necessary to synthesize and purify the polymer were investigated in some detail. The synthesized poly(ether sulfone)s comprise sulfone and ether linkages in addition to reactive carboxylic acid functionality; these active carboxylic acid functional groups were exploited to hold the phenyl sulphonic acid and phenyl phosphonic acid pendants. The phenyl sulphonic acid pendants in VALPSU were easily constructed by altering active carboxylic acid moieties by sulfanilic acid using N,N′-dicyclohexylcarbodiimide (DCC) mediated mild synthetic route, whereas the latter one was built in two steps. Initially, polyphosphoric acid condensation with VALPSU by 4-bromoaniline and next straightforward palladium catalyzed synthetic route, in both of which acidic pendants are clenched by polymer backbone via amide linkage. Without impairing the primary polymeric backbone modified polymers were prepared by varying the stoichiometric ratios of respective combinations. All the polymers were physicochemically characterized and pressed into tablets; electrical contacts were established to study the dielectric properties. Finally, the influence of the acidic pendants on the dielectric properties was examined.","PeriodicalId":17611,"journal":{"name":"Journal: Materials","volume":"70 1","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2016-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77397711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The energy loss (EL) of 5.486 MeV α-particles in ferromagnetic nickel foils was measured at different temperatures of the foils. The temperature of the foils was controlled and recorded using a PC-based temperature controller with an accuracy of ±0.01°C. It is observed that the energy loss in ferromagnetic nickel increases by 2–5% as the material goes from ferromagnetic to paramagnetic state. Thus our results show that the phase transition in ferromagnetic materials affects energy loss.
{"title":"The Energy Loss of α-Particles in Ferromagnetic Nickel at Phase Transition","authors":"U. V. Khadke","doi":"10.1155/2016/4576194","DOIUrl":"https://doi.org/10.1155/2016/4576194","url":null,"abstract":"The energy loss (EL) of 5.486 MeV α-particles in ferromagnetic nickel foils was measured at different temperatures of the foils. The temperature of the foils was controlled and recorded using a PC-based temperature controller with an accuracy of ±0.01°C. It is observed that the energy loss in ferromagnetic nickel increases by 2–5% as the material goes from ferromagnetic to paramagnetic state. Thus our results show that the phase transition in ferromagnetic materials affects energy loss.","PeriodicalId":17611,"journal":{"name":"Journal: Materials","volume":"82 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2016-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73376608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nanoindentation hardness and elastic modulus of the silver/MWCNT (multiwalled carbon nanotubes) composites, fabricated by modified wet mixing technique, are studied in the present work. CNT reinforced silver nanocomposites, fabricated by introducing 4.5 volume percentages of CNT in the silver matrix, have increased elastic modulus and approximately 50% higher hardness than pure nanosilver. It is also observed from the results that the electrical conductivity of the fabricated materials was decreased by increasing the CNTs volume %.
{"title":"CNT Reinforced Silver Nanocomposites: Mechanical and Electrical Studies","authors":"D. Kumar, Sonia Nain, Neena, H. Pal, Ravi Kumar","doi":"10.1155/2016/8629206","DOIUrl":"https://doi.org/10.1155/2016/8629206","url":null,"abstract":"Nanoindentation hardness and elastic modulus of the silver/MWCNT (multiwalled carbon nanotubes) composites, fabricated by modified wet mixing technique, are studied in the present work. CNT reinforced silver nanocomposites, fabricated by introducing 4.5 volume percentages of CNT in the silver matrix, have increased elastic modulus and approximately 50% higher hardness than pure nanosilver. It is also observed from the results that the electrical conductivity of the fabricated materials was decreased by increasing the CNTs volume %.","PeriodicalId":17611,"journal":{"name":"Journal: Materials","volume":"10 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2016-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84806273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The electric field intensity in one-dimensional (1D) quasiperiodic and hybrid photonics band-gap structures is studied in the present paper. The photonic structures are ordered according to Fibonacci, Thue-Morse, Cantor, Rudin-Shapiro, Period-Doubling, Paper-Folding, and Baum-Sweet sequences. The study shows that the electric field intensity is higher for the Thue-Morse multilayer systems. After that the Thue-Morse structure will be combined with a periodic structure to form a hybrid photonic structure. It is shown that this hybrid system is the best for a strong localization of light. The proposed structures have been modeled using the Transfer Matrix Method.
{"title":"Enhancement of Light Localization in Hybrid Thue-Morse/Periodic Photonic Crystals","authors":"R. Asmi, N. Ali, M. Kanzari","doi":"10.1155/2016/9471312","DOIUrl":"https://doi.org/10.1155/2016/9471312","url":null,"abstract":"The electric field intensity in one-dimensional (1D) quasiperiodic and hybrid photonics band-gap structures is studied in the present paper. The photonic structures are ordered according to Fibonacci, Thue-Morse, Cantor, Rudin-Shapiro, Period-Doubling, Paper-Folding, and Baum-Sweet sequences. The study shows that the electric field intensity is higher for the Thue-Morse multilayer systems. After that the Thue-Morse structure will be combined with a periodic structure to form a hybrid photonic structure. It is shown that this hybrid system is the best for a strong localization of light. The proposed structures have been modeled using the Transfer Matrix Method.","PeriodicalId":17611,"journal":{"name":"Journal: Materials","volume":"160 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2016-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77284273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The nc-AlTiN/Si3N4, TiAlN, and TiN coating were deposited using lateral rotating cathodes (LARC) technology on TNMG 160404 cemented carbide turning inserts. Ultrafine grain treated cemented carbide substrates were used in case of TiAlN and TiN inserts. The coated inserts were tested for their hardness and compositions were determined by X-ray diffraction studies. The grain structures of coatings were observed using scanning electron microscopy. Dry cutting tests were performed on AISI 304 stainless steel to compare the performances of these coatings in terms of wear and surface finish imparted to workpiece. 3D confocal laser microscope was used to determine the flank wear. Grey relation analysis was carried out to optimize the machining parameters. Studies reveal that nc-AlTiN/Si3N4 coating showed the highest hardness of 28 GPa. The coating also shows a dense grain structure. Furthermore, in cutting tests even under severe dry cutting conditions, the wear observed was less than the other two coatings and surface finish imparted to work parts was less than 2 μm by this coating.
{"title":"Optimization of Cutting Parameters during Dry Turning of Austenitic Stainless Steel Using nc-AlTiN/Si3N4, TiAlN, and TiN Coated Inserts","authors":"K. V. Prasad, R. Pal, V. Rajendraprasad","doi":"10.1155/2016/3495698","DOIUrl":"https://doi.org/10.1155/2016/3495698","url":null,"abstract":"The nc-AlTiN/Si3N4, TiAlN, and TiN coating were deposited using lateral rotating cathodes (LARC) technology on TNMG 160404 cemented carbide turning inserts. Ultrafine grain treated cemented carbide substrates were used in case of TiAlN and TiN inserts. The coated inserts were tested for their hardness and compositions were determined by X-ray diffraction studies. The grain structures of coatings were observed using scanning electron microscopy. Dry cutting tests were performed on AISI 304 stainless steel to compare the performances of these coatings in terms of wear and surface finish imparted to workpiece. 3D confocal laser microscope was used to determine the flank wear. Grey relation analysis was carried out to optimize the machining parameters. Studies reveal that nc-AlTiN/Si3N4 coating showed the highest hardness of 28 GPa. The coating also shows a dense grain structure. Furthermore, in cutting tests even under severe dry cutting conditions, the wear observed was less than the other two coatings and surface finish imparted to work parts was less than 2 μm by this coating.","PeriodicalId":17611,"journal":{"name":"Journal: Materials","volume":"33 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2016-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87993770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cement pastes and mortars based on ordinary Portland cement containing nitrogen-doped multiwalled carbon nanotubes (MWCNT-Nx) or oxygen-functionalized multiwalled carbon nanotubes (MWCNT-Ox) are investigated. To incorporate MWCNTs into the cementitious matrix, the as-produced carpets are dispersed over periods of 1 and 2 hours in distilled water at pH levels of 1 and 7. The cement pastes are prepared by adding 0.1 wt% of MWCNTs to cement powder, followed by characterization with SEM and X-ray diffraction (XRD) at an early age (first hours of hydration). The mortars are mechanically characterized during the hydration process for a period of 28 days. SEM characterization of cement pastes revealed that the carbon nanotubes are well incorporated in the cementitious matrix, with the hydrated cement grains interconnected by long carbon nanotubes. XRD characterizations demonstrated that, during the hydration of cement pastes, different peaks emerged that were associated with ettringite, hydrated calcium silicate, and calcium hydroxide, among other structures. Results of the compressive strength measurements for mortars simultaneously mixed with MWCNT-Nx and MWCNT-Ox reached an increment of approximately 30% in compressive strength. In addition, density functional theory calculations were performed in nitrogen-doped and oxygen-functionalized carbon nanotubes interacting with a cement grain.
{"title":"Cement Pastes and Mortars Containing Nitrogen-Doped and Oxygen-Functionalized Multiwalled Carbon Nanotubes","authors":"Mauricio Martínez-Alanis, F. López‐Urías","doi":"10.1155/2016/6209192","DOIUrl":"https://doi.org/10.1155/2016/6209192","url":null,"abstract":"Cement pastes and mortars based on ordinary Portland cement containing nitrogen-doped multiwalled carbon nanotubes (MWCNT-Nx) or oxygen-functionalized multiwalled carbon nanotubes (MWCNT-Ox) are investigated. To incorporate MWCNTs into the cementitious matrix, the as-produced carpets are dispersed over periods of 1 and 2 hours in distilled water at pH levels of 1 and 7. The cement pastes are prepared by adding 0.1 wt% of MWCNTs to cement powder, followed by characterization with SEM and X-ray diffraction (XRD) at an early age (first hours of hydration). The mortars are mechanically characterized during the hydration process for a period of 28 days. SEM characterization of cement pastes revealed that the carbon nanotubes are well incorporated in the cementitious matrix, with the hydrated cement grains interconnected by long carbon nanotubes. XRD characterizations demonstrated that, during the hydration of cement pastes, different peaks emerged that were associated with ettringite, hydrated calcium silicate, and calcium hydroxide, among other structures. Results of the compressive strength measurements for mortars simultaneously mixed with MWCNT-Nx and MWCNT-Ox reached an increment of approximately 30% in compressive strength. In addition, density functional theory calculations were performed in nitrogen-doped and oxygen-functionalized carbon nanotubes interacting with a cement grain.","PeriodicalId":17611,"journal":{"name":"Journal: Materials","volume":"17 1","pages":"1-16"},"PeriodicalIF":0.0,"publicationDate":"2016-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78200046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Welsh, M. Kapoor, O. Underwood, R. Martens, G. Thompson, Jeffrey L. Evans
Commercially pure nickel (Ni) was thermomechanically processed to promote an increase in Σ3 special grain boundaries. Engineering the character and chemistry of Σ3 grain boundaries in polycrystalline materials can help in improving physical, chemical, and mechanical properties leading to improved performance. Type-specific grain boundaries (special and random) were characterized using electron backscatter diffraction and the segregation behavior of elements such as Si, Al, C, O, P, Cr, Mg, Mn, B, and Fe, at the atomic level, was studied as a function of grain boundary character using atom probe tomography. These results showed that the random grain boundaries were enriched with impurities to include metal oxides, while Σ3 special grain boundaries showed little to no impurities at the grain boundaries. In addition, the influence of annealing time on the concentration of segregants on random grain boundaries was analyzed and showed clear evidence of increased concentration of segregants as annealing time was increased.
{"title":"Influence of Grain Boundary Character and Annealing Time on Segregation in Commercially Pure Nickel","authors":"S. Welsh, M. Kapoor, O. Underwood, R. Martens, G. Thompson, Jeffrey L. Evans","doi":"10.1155/2016/4597271","DOIUrl":"https://doi.org/10.1155/2016/4597271","url":null,"abstract":"Commercially pure nickel (Ni) was thermomechanically processed to promote an increase in Σ3 special grain boundaries. Engineering the character and chemistry of Σ3 grain boundaries in polycrystalline materials can help in improving physical, chemical, and mechanical properties leading to improved performance. Type-specific grain boundaries (special and random) were characterized using electron backscatter diffraction and the segregation behavior of elements such as Si, Al, C, O, P, Cr, Mg, Mn, B, and Fe, at the atomic level, was studied as a function of grain boundary character using atom probe tomography. These results showed that the random grain boundaries were enriched with impurities to include metal oxides, while Σ3 special grain boundaries showed little to no impurities at the grain boundaries. In addition, the influence of annealing time on the concentration of segregants on random grain boundaries was analyzed and showed clear evidence of increased concentration of segregants as annealing time was increased.","PeriodicalId":17611,"journal":{"name":"Journal: Materials","volume":"5 1","pages":"1-15"},"PeriodicalIF":0.0,"publicationDate":"2016-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83619613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The experimental study of water vapour adsorption phenomenon on a zeolite, by dielectric relaxation measurement, makes it possible to determine the variations in the exchangeable cation hopping activation energy, on the surface of the solid, in relation to the number of adsorbed molecules. The present work shows that it is possible to explain the change observed in the energy, by means of simple assumptions based, on the one hand, on the models used in order to simulate the adsorption process and, on the other hand, on the distribution of the molecules adsorbed near the exchangeable cations. Thus, the phenomenological interpretation suggested here, about the change in the exchangeable cation hopping energy, obtained by dielectric relaxation measurement, makes us with a mind to conceive a simple method for explaining the results leading to new information on the organization of the first adsorbed molecules on the surface of the studied zeolite. Then, it can be verified that these conclusions confirm the assumptions already developed for interpreting the inferences from previous experiments carried out by means of other techniques.
{"title":"Behavioural Change according to the Si/Al Ratio of Successive Na-Mordenites Observed through Their Dielectric Relaxation during Water Vapour Adsorption Process","authors":"S. Diaby","doi":"10.1155/2016/7532951","DOIUrl":"https://doi.org/10.1155/2016/7532951","url":null,"abstract":"The experimental study of water vapour adsorption phenomenon on a zeolite, by dielectric relaxation measurement, makes it possible to determine the variations in the exchangeable cation hopping activation energy, on the surface of the solid, in relation to the number of adsorbed molecules. The present work shows that it is possible to explain the change observed in the energy, by means of simple assumptions based, on the one hand, on the models used in order to simulate the adsorption process and, on the other hand, on the distribution of the molecules adsorbed near the exchangeable cations. Thus, the phenomenological interpretation suggested here, about the change in the exchangeable cation hopping energy, obtained by dielectric relaxation measurement, makes us with a mind to conceive a simple method for explaining the results leading to new information on the organization of the first adsorbed molecules on the surface of the studied zeolite. Then, it can be verified that these conclusions confirm the assumptions already developed for interpreting the inferences from previous experiments carried out by means of other techniques.","PeriodicalId":17611,"journal":{"name":"Journal: Materials","volume":"23 1","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2016-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75159404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work we investigated the performance aspects of addition of used motor oils (UMO) to neat and crumb rubber modified asphalts (CRMA) and related that to the change of molecular size distribution of modified asphalt’s fractions; asphaltenes, saturates, naphthene aromatics, and polar aromatics. Based on the results of temperature sweep viscoelastic tests, addition of crumb rubber modifier (CRM) alone or with UMO results in the formation of internal network within the modified asphalt. Based on the results of short and long term aged asphalts, the utilization of combination of UMO and CRM enhanced the aging behavior of asphalt. Bending beam rheometer was utilized to investigate the low temperature behavior of UMO modified asphalts. Based on those tests, the utilization of the UMO and CRM enhanced the low temperature properties of asphalts. Based on the results of the asphalt separation tests and the Gel Permeation Chromatography (GPC) analysis, it was found that saturates and naphthene aromatics are the two asphalt fractions that have similar molecular size fractions as those of UMO. However, UMO only shifts the molecular sizes of saturates after interaction with asphalt. Results also show that polar aromatics pose higher molecular size structures than UMO.
{"title":"Investigation of the Physical and Molecular Properties of Asphalt Binders Processed with Used Motor Oils","authors":"Mohyeldin Ragab, M. Abdelrahman","doi":"10.1155/2015/632534","DOIUrl":"https://doi.org/10.1155/2015/632534","url":null,"abstract":"In this work we investigated the performance aspects of addition of used motor oils (UMO) to neat and crumb rubber modified asphalts (CRMA) and related that to the change of molecular size distribution of modified asphalt’s fractions; asphaltenes, saturates, naphthene aromatics, and polar aromatics. Based on the results of temperature sweep viscoelastic tests, addition of crumb rubber modifier (CRM) alone or with UMO results in the formation of internal network within the modified asphalt. Based on the results of short and long term aged asphalts, the utilization of combination of UMO and CRM enhanced the aging behavior of asphalt. Bending beam rheometer was utilized to investigate the low temperature behavior of UMO modified asphalts. Based on those tests, the utilization of the UMO and CRM enhanced the low temperature properties of asphalts. Based on the results of the asphalt separation tests and the Gel Permeation Chromatography (GPC) analysis, it was found that saturates and naphthene aromatics are the two asphalt fractions that have similar molecular size fractions as those of UMO. However, UMO only shifts the molecular sizes of saturates after interaction with asphalt. Results also show that polar aromatics pose higher molecular size structures than UMO.","PeriodicalId":17611,"journal":{"name":"Journal: Materials","volume":"33 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2015-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82152336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Polymeric nanofibers have been produced in the last few years by electrospinning of polymer solutions. Polyvinyl alcohol (PVA) was the selected polymer for the preparation of nanofibers. Processing parameters like flow rate, needle gauge, needle to collector distance, and molarity of the solution have been optimized during electrospinning process. Sol-gel method has been used for the preparation of thermoelectric cobaltite nanoparticles having composition NaCoO2. Sol-gel combined electrospinning technique was used to prepare the composites of the NaCoO2 with PVA nanofibers. X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) have been used for the structural analysis of the prepared samples. Scanning electron microscopy (SEM) was used to observe the morphology of the prepared fibers. SEM micrographs showed that, by increasing the flow rate, diameter of the fibers increased from 185 nm to 200 nm. Two-probe method and Advantageous Transient Plane Source (ATPS) were used to study the electrical and thermal transport properties, respectively. Thermal conductivity and electrical conductivity showed a direct dependence on temperature. It was observed that particles, sample has lower thermal conductivity (0.610 W/m-K) as compared to that of composite nanofibers (1.129 W/m-K). The measurements reported are novel and are useful for energy applications.
{"title":"Structural and Thermophysical Studies of Composite Na-Cobaltite Electrospun Nanofibers","authors":"Fatima-tuz-Zahra, M. Anis-Ur-Rehman","doi":"10.1155/2015/838957","DOIUrl":"https://doi.org/10.1155/2015/838957","url":null,"abstract":"Polymeric nanofibers have been produced in the last few years by electrospinning of polymer solutions. Polyvinyl alcohol (PVA) was the selected polymer for the preparation of nanofibers. Processing parameters like flow rate, needle gauge, needle to collector distance, and molarity of the solution have been optimized during electrospinning process. Sol-gel method has been used for the preparation of thermoelectric cobaltite nanoparticles having composition NaCoO2. Sol-gel combined electrospinning technique was used to prepare the composites of the NaCoO2 with PVA nanofibers. X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) have been used for the structural analysis of the prepared samples. Scanning electron microscopy (SEM) was used to observe the morphology of the prepared fibers. SEM micrographs showed that, by increasing the flow rate, diameter of the fibers increased from 185 nm to 200 nm. Two-probe method and Advantageous Transient Plane Source (ATPS) were used to study the electrical and thermal transport properties, respectively. Thermal conductivity and electrical conductivity showed a direct dependence on temperature. It was observed that particles, sample has lower thermal conductivity (0.610 W/m-K) as compared to that of composite nanofibers (1.129 W/m-K). The measurements reported are novel and are useful for energy applications.","PeriodicalId":17611,"journal":{"name":"Journal: Materials","volume":"2 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2015-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76571907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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