Solar power holds great potential as an alternative energy source, but current photovoltaic cells have much room for improvement in cost and efficiency. Our objective was to develop metal nanostructures whose surface plasmon resonance (SPR) spectra closely match the solar spectrum to enhance light absorption and scattering. We employed the finite-difference time-domain simulation method to evaluate the effect of varying key parameters. A novel nanostructure with SPR absorption matching a region of the solar spectrum (300 to 1500 nm) that contains 90% of solar energy was successfully designed. This structure consists of a large gold-silica core-shell structure with smaller gold nanoparticles and nanorods on its surface. Such complex nanostructures are promising for broad and tunable absorption spectra. In addition, we investigated the SPR of silver nanoparticle arrays, which can achieve scattering close to the solar spectrum. We demonstrated an improvement in efficiency of over 30% with optimal nanoparticle radius and periods of 75 nm and 325 nm, respectively. In combination, our studies enable high-efficiency, tunable, and cost-effective enhancement of both light absorption and scattering, which has potential applications in solar energy conversion as well as biomedical imaging.
{"title":"Design of Novel Metal Nanostructures for Broadband Solar Energy Conversion","authors":"K. A. Zhang, D. Ma, Ying-Chih Pu, Yat Li","doi":"10.1155/2015/147423","DOIUrl":"https://doi.org/10.1155/2015/147423","url":null,"abstract":"Solar power holds great potential as an alternative energy source, but current photovoltaic cells have much room for improvement in cost and efficiency. Our objective was to develop metal nanostructures whose surface plasmon resonance (SPR) spectra closely match the solar spectrum to enhance light absorption and scattering. We employed the finite-difference time-domain simulation method to evaluate the effect of varying key parameters. A novel nanostructure with SPR absorption matching a region of the solar spectrum (300 to 1500 nm) that contains 90% of solar energy was successfully designed. This structure consists of a large gold-silica core-shell structure with smaller gold nanoparticles and nanorods on its surface. Such complex nanostructures are promising for broad and tunable absorption spectra. In addition, we investigated the SPR of silver nanoparticle arrays, which can achieve scattering close to the solar spectrum. We demonstrated an improvement in efficiency of over 30% with optimal nanoparticle radius and periods of 75 nm and 325 nm, respectively. In combination, our studies enable high-efficiency, tunable, and cost-effective enhancement of both light absorption and scattering, which has potential applications in solar energy conversion as well as biomedical imaging.","PeriodicalId":14329,"journal":{"name":"International Journal of Spectroscopy","volume":"43 1","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2015-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82365937","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}
Shanmugavel Chinnathambi, Shanmugavel Chinnathambi, S. Karthikeyan, D. Velmurugan, N. Hanagata, N. Hanagata, P. Aruna, S. Ganesan
The interaction of antimetabolite 5-fluorouracil (5FU) with bovine serum albumin (BSA) under UVC (253.7 nm) irradiation was investigated in the present study using UV-Vis spectroscopy, steady state/time resolved fluorescence spectroscopic techniques. The stability of protein was found to be very strong when BSA gets bind to 5FU and moreover it is compared with the free BSA under UVC irradiation. From the fluorescence spectroscopic study, the stability of the complex was found to acquire 2-fold stronger than free protein. From the molecular modelling studies, we came to know the hydrogen bonds between BSA and antimetabolite 5FU are strong, up to 70.4 J/m2 under UVC irradiation.
{"title":"Effect of Moderate UVC Irradiation on Bovine Serum Albumin and Complex with Antimetabolite 5-Fluorouracil: Fluorescence Spectroscopic and Molecular Modelling Studies","authors":"Shanmugavel Chinnathambi, Shanmugavel Chinnathambi, S. Karthikeyan, D. Velmurugan, N. Hanagata, N. Hanagata, P. Aruna, S. Ganesan","doi":"10.1155/2015/315764","DOIUrl":"https://doi.org/10.1155/2015/315764","url":null,"abstract":"The interaction of antimetabolite 5-fluorouracil (5FU) with bovine serum albumin (BSA) under UVC (253.7 nm) irradiation was investigated in the present study using UV-Vis spectroscopy, steady state/time resolved fluorescence spectroscopic techniques. The stability of protein was found to be very strong when BSA gets bind to 5FU and moreover it is compared with the free BSA under UVC irradiation. From the fluorescence spectroscopic study, the stability of the complex was found to acquire 2-fold stronger than free protein. From the molecular modelling studies, we came to know the hydrogen bonds between BSA and antimetabolite 5FU are strong, up to 70.4 J/m2 under UVC irradiation.","PeriodicalId":14329,"journal":{"name":"International Journal of Spectroscopy","volume":"71 1","pages":"1-12"},"PeriodicalIF":0.0,"publicationDate":"2015-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86236858","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 paper deals with the spectral properties of dyes with interfragmental charge transfer, in particular, derivatives of 2-(3-coumaroyl)benzopyrylium (CBP) perchlorates. The positions of long-wavelength absorption and emission bands, quantum yields, and lifetimes of fluorescence were measured, mostly in aprotic solvents. Regression analysis of the relationship between the spectral characteristics of CBP and the main solvent parameters (polarity, polarisability, nucleophilicity, and electrophilicity) was carried out. It was found that the characteristics of CBP depend mainly on two solvent parameters—polarity and/or nucleophilicity. An increase in these parameters results in a hypsochromic shift of absorption bands and a decrease of lifetimes and fluorescence intensity. The positions of the emission bands can demonstrate either hypsochromism or bathochromism, depending on the nature of the substituents. The solvatofluorochromic effects are not as strong as the solvatochromic ones. We believe that the spectral behaviour of CBP can be explained by cation depolarisation and by a decrease in the stability of nucleophilic complexes with solvent molecules that is associated with interfragmental charge transfer following excitation, relaxation, and radiative deactivation of the excited state.
{"title":"Spectral Properties of Dyes with Interfragmental Charge Transfer: Solvatochromism and Solvatofluorochromism of 2-(3-Coumaroyl)-benzopyrylium Perchlorates","authors":"E. V. Sanin, A. I. Novikov, A. Roshal","doi":"10.1155/2014/508153","DOIUrl":"https://doi.org/10.1155/2014/508153","url":null,"abstract":"The paper deals with the spectral properties of dyes with interfragmental charge transfer, in particular, derivatives of 2-(3-coumaroyl)benzopyrylium (CBP) perchlorates. The positions of long-wavelength absorption and emission bands, quantum yields, and lifetimes of fluorescence were measured, mostly in aprotic solvents. Regression analysis of the relationship between the spectral characteristics of CBP and the main solvent parameters (polarity, polarisability, nucleophilicity, and electrophilicity) was carried out. \u0000It was found that the characteristics of CBP depend mainly on two solvent parameters—polarity and/or nucleophilicity. An increase in these parameters results in a hypsochromic shift of absorption bands and a decrease of lifetimes and fluorescence intensity. The positions of the emission bands can demonstrate either hypsochromism or bathochromism, depending on the nature of the substituents. The solvatofluorochromic effects are not as strong as the solvatochromic ones. We believe that the spectral behaviour of CBP can be explained by cation depolarisation and by a decrease in the stability of nucleophilic complexes with solvent molecules that is associated with interfragmental charge transfer following excitation, relaxation, and radiative deactivation of the excited state.","PeriodicalId":14329,"journal":{"name":"International Journal of Spectroscopy","volume":"1 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2014-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90209829","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}
Spectrometries probing relaxation and retardation phenomena, such as dielectric, mechanical, and impedance spectroscopies, often require the analyses with both susceptibilities spectra and its reciprocals (e.g., complex permittivity and electric modulus, mechanical compliance and mechanical modulus, and impedance and admittance). In the present paper, the geometric relation between and is derived and the procedure to convert into on a Cole-Cole diagram is proposed. This method helps us to relate them intuitively and yields clearer understanding on their interrelations. Moreover, it opens the new route for the geometric approach to derive many mathematical properties of spectra. The relation between peak position of spectrum and that of spectrum and the shape of spectra are discussed on the basis of this method.
{"title":"Graphical Conversion between Compliance and Modulus, Permittivity and Electric Modulus, and Impedance and Admittance","authors":"M. Nakanishi","doi":"10.1155/2014/538206","DOIUrl":"https://doi.org/10.1155/2014/538206","url":null,"abstract":"Spectrometries probing relaxation and retardation phenomena, such as dielectric, mechanical, and impedance spectroscopies, often require the analyses with both susceptibilities spectra and its reciprocals (e.g., complex permittivity and electric modulus, mechanical compliance and mechanical modulus, and impedance and admittance). In the present paper, the geometric relation between and is derived and the procedure to convert into on a Cole-Cole diagram is proposed. This method helps us to relate them intuitively and yields clearer understanding on their interrelations. Moreover, it opens the new route for the geometric approach to derive many mathematical properties of spectra. The relation between peak position of spectrum and that of spectrum and the shape of spectra are discussed on the basis of this method.","PeriodicalId":14329,"journal":{"name":"International Journal of Spectroscopy","volume":"25 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2014-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79646958","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}
J. Nwaboh, O. Witzel, A. Pogány, O. Werhahn, V. Ebert
We employed a comparison method to determine the optical path length of gas cells which can be used in spectroscopic setup based on laser absorption spectroscopy or FTIR. The method is based on absorption spectroscopy itself. A reference gas cell, whose length is ap rioriknown and desirably traceable to the international system of units (SI), and a gas mixture are used to calibrate the path length of a cell under test. By comparing spectra derived from pressure-dependent measurements on the two cells, the path length of the gas cell under test is determined. The method relies neither on the knowledge of the gas concentration nor on the line strength parameter of the probed transition which is very rarely traceable to the SI and of which the uncertainty is often relatively large. The method is flexible such that any infrared light source and infrared active molecule with isolated lines can be used. We elaborate on the method, substantiate the method by reporting results of this calibration procedure applied to multipass and single pass gas cells of lengths from 0.38 m to 21 m, and compare this to other methods. The relative combined uncertainty of the path length results determined using the comparison method was found to be in the ±0.4% range.
{"title":"Optical Path Length Calibration: A Standard Approach for Use in Absorption Cell-Based IR-Spectrometric Gas Analysis","authors":"J. Nwaboh, O. Witzel, A. Pogány, O. Werhahn, V. Ebert","doi":"10.1155/2014/132607","DOIUrl":"https://doi.org/10.1155/2014/132607","url":null,"abstract":"We employed a comparison method to determine the optical path length of gas cells which can be used in spectroscopic setup based on laser absorption spectroscopy or FTIR. The method is based on absorption spectroscopy itself. A reference gas cell, whose length is ap rioriknown and desirably traceable to the international system of units (SI), and a gas mixture are used to calibrate the path length of a cell under test. By comparing spectra derived from pressure-dependent measurements on the two cells, the path length of the gas cell under test is determined. The method relies neither on the knowledge of the gas concentration nor on the line strength parameter of the probed transition which is very rarely traceable to the SI and of which the uncertainty is often relatively large. The method is flexible such that any infrared light source and infrared active molecule with isolated lines can be used. We elaborate on the method, substantiate the method by reporting results of this calibration procedure applied to multipass and single pass gas cells of lengths from 0.38 m to 21 m, and compare this to other methods. The relative combined uncertainty of the path length results determined using the comparison method was found to be in the ±0.4% range.","PeriodicalId":14329,"journal":{"name":"International Journal of Spectroscopy","volume":"19 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2014-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84450965","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}
A. K. Srivastava, A. K. Pandey, S. Pandey, P. Nayak, B. Narayana, B. Sarojini, N. Misra
A test on calculated vibrational modes of 2-(2,6-dichlorophenyl)-N-(1,3-thiazol-2yl) acetamide using ab initio density functional method has been performed. The calculated harmonic vibrational frequencies are scaled via two schemes, uniform, , and nonuniform, . Scaled vibrational modes are compared with experimental FTIR bands. A good correlation is shown between scaled frequencies with the correlation coefficient, . This clearly shows that both schemes efficiently reproduce observed spectrum. However, a close investigation of individual normal modes reveals that nonuniform scaling performs much better than uniform scaling especially in the high frequency region.
用从头算密度泛函法对2-(2,6-二氯苯基)- n -(1,3-噻唑-2基)乙酰胺的计算振动模态进行了测试。计算出的谐波振动频率通过均匀和非均匀两种格式进行缩放。将尺度振动模式与实验波段进行了比较。缩放后的频率与相关系数之间具有良好的相关性。这清楚地表明两种方案都能有效地再现观测到的光谱。然而，对单个正态模态的仔细研究表明，非均匀标度比均匀标度表现得更好，特别是在高频区域。
{"title":"Uniform versus Nonuniform Scaling of Normal Modes Predicted by Ab Initio Calculations: A Test on 2-(2,6-Dichlorophenyl)-N-(1,3-thiazol-2yl) Acetamide","authors":"A. K. Srivastava, A. K. Pandey, S. Pandey, P. Nayak, B. Narayana, B. Sarojini, N. Misra","doi":"10.1155/2014/649268","DOIUrl":"https://doi.org/10.1155/2014/649268","url":null,"abstract":"A test on calculated vibrational modes of 2-(2,6-dichlorophenyl)-N-(1,3-thiazol-2yl) acetamide using ab initio density functional method has been performed. The calculated harmonic vibrational frequencies are scaled via two schemes, uniform, , and nonuniform, . Scaled vibrational modes are compared with experimental FTIR bands. A good correlation is shown between scaled frequencies with the correlation coefficient, . This clearly shows that both schemes efficiently reproduce observed spectrum. However, a close investigation of individual normal modes reveals that nonuniform scaling performs much better than uniform scaling especially in the high frequency region.","PeriodicalId":14329,"journal":{"name":"International Journal of Spectroscopy","volume":"263 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2014-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75106849","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 the present work we have reported the optimized ground state geometry, harmonic vibrational frequencies, NMR chemical shifts, NBO analysis, and molecular electrostatic potential surface map of the title compound using DFT/B3LYP/6-311
{"title":"Quantum Chemical and Spectroscopic Investigations of (Ethyl 4 hydroxy-3-((E)-(pyren-1-ylimino)methyl)benzoate) by DFT Method","authors":"Diwaker, A. Gupta","doi":"10.1155/2014/841593","DOIUrl":"https://doi.org/10.1155/2014/841593","url":null,"abstract":"In the present work we have reported the optimized ground state geometry, harmonic vibrational frequencies, NMR chemical shifts, NBO analysis, and molecular electrostatic potential surface map of the title compound using DFT/B3LYP/6-311","PeriodicalId":14329,"journal":{"name":"International Journal of Spectroscopy","volume":"33 1","pages":"1-15"},"PeriodicalIF":0.0,"publicationDate":"2014-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76551429","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}
A simple and sensitive kinetic spectrophotometric method was developed for the determination of fexofenadine hydrochloride in bulk and pharmaceutical preparations. The method is based on a kinetic investigation of the oxidation reaction of fexofenadine using alkaline potassium permanganate as an oxidizing agent at room temperature. The reaction is followed spectrophotometrically by measuring the increase of absorbance owing to the formation of manganate ion at 610 nm. The initial rate and fixed time (at 15 min) methods are utilized for construction of calibration graphs. All the reaction conditions for the proposed method have been studied. The linearity range was found to be 2.5–50.0 μg mL−1 with detection limit of 0.055 μg mL−1 for both initial rate and fixed time methods. The proposed method was applied successfully for the determination of fexofenadine in pharmaceutical formulations; the percentage recoveries were 99.98–101.96%. The results obtained were compared statistically with those obtained by the official method and showed no significant differences regarding accuracy and precision.
{"title":"New Kinetic Spectrophotometric Method for Determination of Fexofenadine Hydrochloride in Pharmaceutical Formulations","authors":"S. Ashour, Mouhammed Khateeb","doi":"10.1155/2014/308087","DOIUrl":"https://doi.org/10.1155/2014/308087","url":null,"abstract":"A simple and sensitive kinetic spectrophotometric method was developed for the determination of fexofenadine hydrochloride in bulk and pharmaceutical preparations. The method is based on a kinetic investigation of the oxidation reaction of fexofenadine using alkaline potassium permanganate as an oxidizing agent at room temperature. The reaction is followed spectrophotometrically by measuring the increase of absorbance owing to the formation of manganate ion at 610 nm. The initial rate and fixed time (at 15 min) methods are utilized for construction of calibration graphs. All the reaction conditions for the proposed method have been studied. The linearity range was found to be 2.5–50.0 μg mL−1 with detection limit of 0.055 μg mL−1 for both initial rate and fixed time methods. The proposed method was applied successfully for the determination of fexofenadine in pharmaceutical formulations; the percentage recoveries were 99.98–101.96%. The results obtained were compared statistically with those obtained by the official method and showed no significant differences regarding accuracy and precision.","PeriodicalId":14329,"journal":{"name":"International Journal of Spectroscopy","volume":"42 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2014-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85550526","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}
Naringin-Bi (III) complex (Narb) was prepared and analysed by UV-Visible absorption and fluorescence measurements. The inclusion complex of Narb with β-Cyclodextrin (β-CD) was characterized by the UV-Visible absorption, Infrared, scanning dlectron microscopic, and X-ray diffractometric techniques. The stoichiometry of the inclusion complex of Narb with β-CD was 1 : 1 with a binding constant of 5.18 × 102 mol−1 dm3. The interaction of Narb with Calf Thymus DNA (ctDNA) was investigated in the presence and the absence of β-CD. The binding constants for the interaction of Narb with ctDNA in the absence and the presence of β-CD were 1.29 × 105 mol−1 dm3 and 6.89 × 104 mol−1 dm3, respectively. The Stern-Volmer constants for the interaction of Narb with ctDNA in the absence and the presence of β-CD were 1.25 × 104 mol−1 dm3 and 5.10 × 103 mol−1 dm3, respectively. The lowering of the binding affinity and the were observed for the interaction of Narb with ctDNA in the presence of β-CD.
{"title":"Binding of the Bi (III) Complex of Naringin with β-Cyclodextrin/Calf Thymus DNA: Absorption and Fluorescence Characteristics","authors":"Sameena Yousuf, I. V. Enoch","doi":"10.1155/2014/562160","DOIUrl":"https://doi.org/10.1155/2014/562160","url":null,"abstract":"Naringin-Bi (III) complex (Narb) was prepared and analysed by UV-Visible absorption and fluorescence measurements. The inclusion complex of Narb with β-Cyclodextrin (β-CD) was characterized by the UV-Visible absorption, Infrared, scanning dlectron microscopic, and X-ray diffractometric techniques. The stoichiometry of the inclusion complex of Narb with β-CD was 1 : 1 with a binding constant of 5.18 × 102 mol−1 dm3. The interaction of Narb with Calf Thymus DNA (ctDNA) was investigated in the presence and the absence of β-CD. The binding constants for the interaction of Narb with ctDNA in the absence and the presence of β-CD were 1.29 × 105 mol−1 dm3 and 6.89 × 104 mol−1 dm3, respectively. The Stern-Volmer constants for the interaction of Narb with ctDNA in the absence and the presence of β-CD were 1.25 × 104 mol−1 dm3 and 5.10 × 103 mol−1 dm3, respectively. The lowering of the binding affinity and the were observed for the interaction of Narb with ctDNA in the presence of β-CD.","PeriodicalId":14329,"journal":{"name":"International Journal of Spectroscopy","volume":"48 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2014-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79163582","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}
M. Veitmann, R. Jumeau, P. Bourson, M. Ferriol, F. Lahure
Studies of high temperature oxidation of polyethylene are not much present in the literature though it can really be a problem especially in polymer production and processing. This study aims to detect oxidation flaws in polyethylene and to determine their impact on polymer structure and properties. Besides, we suggest a method via PLS-regression to determine the degree of flaws that can occur during polymer processing due to oxidation. Several kinds of oxidation flaws were reproduced in laboratory at 150°C in an oven operating in air and Raman spectroscopy analysis was performed on each sample. Using statistical tools as chemometrics on these spectra, we have built a Partial Least Square (PLS) model able to predict the oxidation degree of flaws. Interpretation of the model construction and further characterization tests show that oxidation can be followed with the evolution of the crystalline carbon group and of the created carbonyl functions. Finally we suggest possible mechanisms which can explain the high temperature oxidation process in LPDE, and we link them to the modification of the material properties.
{"title":"Understanding and Control of High Temperature Oxidation Flaws of Low-Density Poly(ethylene) with Raman Spectroscopy","authors":"M. Veitmann, R. Jumeau, P. Bourson, M. Ferriol, F. Lahure","doi":"10.1155/2014/194563","DOIUrl":"https://doi.org/10.1155/2014/194563","url":null,"abstract":"Studies of high temperature oxidation of polyethylene are not much present in the literature though it can really be a problem especially in polymer production and processing. This study aims to detect oxidation flaws in polyethylene and to determine their impact on polymer structure and properties. Besides, we suggest a method via PLS-regression to determine the degree of flaws that can occur during polymer processing due to oxidation. Several kinds of oxidation flaws were reproduced in laboratory at 150°C in an oven operating in air and Raman spectroscopy analysis was performed on each sample. Using statistical tools as chemometrics on these spectra, we have built a Partial Least Square (PLS) model able to predict the oxidation degree of flaws. Interpretation of the model construction and further characterization tests show that oxidation can be followed with the evolution of the crystalline carbon group and of the created carbonyl functions. Finally we suggest possible mechanisms which can explain the high temperature oxidation process in LPDE, and we link them to the modification of the material properties.","PeriodicalId":14329,"journal":{"name":"International Journal of Spectroscopy","volume":"51 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2014-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89467569","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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