Academic literature on the topic 'TG/DTG and DSC'
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Journal articles on the topic "TG/DTG and DSC"
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Charmas, Barbara, Karolina Kucio, Volodymyr Sydorchuk, Svitlana Khalameida, Magdalena Zięzio, and Aldona Nowicka. "Characterization of Multimodal Silicas Using TG/DTG/DTA, Q-TG, and DSC Methods." Colloids and Interfaces 3, no. 1 (December 28, 2018): 6. http://dx.doi.org/10.3390/colloids3010006.
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The formation of hierarchical, multimodal porosity materials with controlled shape and size of pores is the essential challenge in materials science. Properties of silica materials depend largely on different features: crystal structure, dispersity, surface composition, and porosity as well as the method of preparation and possible modification. In this paper, multimodal silicas obtained using different additives are presented. A-50 and A-380 aerosils and wide-porous SiO2 milled at 300 rpm were used as the additives in the sol stage at 20 °C, the sol–gel stage followed by hydrothermal modification (HTT) at 200 °C, or in the mechanochemical treatment (MChT) process. The characterizations were made by application of N2 adsorption/desorption, SEM imaging, quasi-isothermal thermogravimetry (Q-TG), dynamic thermogravimetry/derivative thermogravimetry/differential thermal analysis (TG/DTG/DTA), and cryoporometry differential scanning calorimetry (DSC) methods. Results showed that such a one-step preparation method is convenient and makes it possible to obtain multimodal silicas of differentiated porous structures and surface chemistry.
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Pereira, Bárbara Luísa Corradi, Angélica de Cássia Oliveira Carneiro, Ana Márcia Macedo Ladeira Carvalho, Paulo Fernando Trugilho, Isabel Cristina Nogueira Alves Melo, and Aylson Costa Oliveira. "Estudo da degradação térmica da madeira de Eucalyptus através de termogravimetria e calorimetria." Revista Árvore 37, no. 3 (June 2013): 567–76. http://dx.doi.org/10.1590/s0100-67622013000300020.
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O objetivo deste trabalho foi avaliar a degradação térmica da madeira de diferentes clones de Eucalyptus, por meio de análises termogravimétrica (TG/DTG) e de calorimetria exploratória diferencial (DSC), estabelecendo-se suas relações com a produção de carvão vegetal. Foram utilizados seis clones de Eucalyptus spp. aos 7,5 anos de idade, provenientes de um teste clonal pertencente a uma empresa florestal. Foram realizadas as análises TG/DTG e DSC, sob atmosfera de gás nitrogênio. As curvas TG/DTG mostraram três faixas de degradação térmica, atribuídas à secagem da madeira e à degradação de hemiceluloses e celulose. Não foi detectada faixa específica de degradação de lignina. As curvas DSC evidenciaram um pico endotérmico entre as temperaturas de 50 e 100 ºC, o que pode ser atribuído à perda de água da madeira. A liberação de calor iniciou-se em temperaturas acima de 275 ºC, para todos os clones avaliados, sendo observados dois picos exotérmicos. As análises térmicas da madeira (TG/DTG e DSC) não apresentaram variações expressivas entre os clones. Conclui-se que, através das técnicas estudadas, é possível identificar as principais fases das reações de liberação ou absorção de energia e perda de massa, que estão diretamente ligadas à qualidade do carvão vegetal.
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Prasad, M. R. R., K. Sudhakarbabu, B. Sreedhar, and D. Keerthi Devi. "A simultaneous TG-DTG-DSC-quadrupole mass spectrometric study." Journal of Thermal Analysis and Calorimetry 116, no. 2 (January 18, 2014): 1027–31. http://dx.doi.org/10.1007/s10973-013-3558-5.
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MORAIS, Francisca Edivânia, Sheila Pricila Marques CABRAL, Eliane Gonçalves ARAUJO, Carlos Alberto MARTINEZ-HUITLE, and Nedja Suely FERNANDES. "THERMAL BEHAVIOR OF PARACETAMOL AND TABLETS OF REFERENCE, GENÉRIC AND SIMILAR." Periódico Tchê Química 09, no. 17 (January 20, 2012): 28–37. http://dx.doi.org/10.52571/ptq.v9.n17.2011.17_periodico17_pgs_17_27.pdf.
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The present study utilized the thermoanalytical techniques (TG, DTG, DTA and DSC) to evaluate the thermal behavior of tablets containing paracetamol and marketed as reference, generic and similar. The samples were also characterized by IR, X-ray diffraction and SEM. The TG/DTG curves presented similar behaviour indicanting a low influence of the excipients present in pharmaceutical formulations. The DTA and DSC curves showed an endothermic peak between about 165.0 and 195.0 oC characteristic of melting of paracetamol in all samples. The X-ray diffraction patterns showed similarities and characterized the compounds as crystallines. The micrographs indicated heterogeneity in particle size.
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Hatakeyama, Tatsuko. "DSC,DTA,TG." Kobunshi 40, no. 4 (1991): 264–67. http://dx.doi.org/10.1295/kobunshi.40.264.
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Miyazaki, Caroline Lumi, Igor Studart Medeiros, Jivaldo do Rosário Matos, and Leonardo Eloy Rodrigues Filho. "Thermal characterization of dental composites by TG/DTG and DSC." Journal of Thermal Analysis and Calorimetry 102, no. 1 (March 20, 2010): 361–67. http://dx.doi.org/10.1007/s10973-010-0739-3.
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Tita, Ioana Cristina, Bogdan Tita, Claudia Crina Toma, Eleonora Marian, and Laura Vicas. "Thermal Behavoiur of Valsartan Active Substance and in Pharmaceutical Products." Revista de Chimie 68, no. 10 (November 15, 2017): 2307–10. http://dx.doi.org/10.37358/rc.17.10.5874.
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G/DTG and DSC curves provide important information regarding the physical properties of the pharmaceutical compounds (stability, compatibility, polymorphism, kinetic analysis, phase transitions etc). The thermal behaviour of valsartan was studied under dynamic nitrogen atmosphere, in comparison with pharmaceutical products containing the corresponding active substances. Also, the FT�IR spectra and X-ray diffactogram of the same samples were recorded. The main conclusion of this comparative study was that TG / DTG and DSC assays along with FT-IR spectra and X-ray diffractograms provide credible data for differences between active substance and pharmaceutical forms.
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Kaczmarska, Karolina, Sylwia Żymankowska-Kumon, Łukasz Byczyński, Beata Grabowska, Artur Bobrowski, and Sylwia Cukrowicz. "Thermoanalytical studies (TG–DTG–DSC, Py–GC/MS) of sodium carboxymethyl starch with different degrees of substitution." Journal of Thermal Analysis and Calorimetry 138, no. 6 (November 2, 2019): 4417–25. http://dx.doi.org/10.1007/s10973-019-08892-4.
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Abstract The paper presents the results of thermal analysis of polymer material in the form of starch derivatives in the form of sodium carboxymethyl starch (CMS–Na) with degree of substitution (DS) in the range 0.2–0.9 for the preparation of foundry binder. In this work, the thermal behavior of the modified starch and qualitative assessment of degradation products released during pyrolysis were determined and comprised. The analysis of the course of progressive decomposition of the starch material under controlled heating in the range of 25–1000 °C in anaerobic atmosphere was based on the results of thermal analysis methods (TG–DTG–DSC) in combination with the results of pyrolysis–gas chromatography–mass spectrometry (Py–GC/MS). The detailed TG–DTG–DSC analysis allowed to determine and compare the temperature at which the process of decomposition of carboxymethyl starches sodium salts with different degrees of substitution begins and to determine the course of its degradation under conditions corresponding to the contact of the foundry binder in the form of starch material with liquid metal (conditions like in foundry mold). Thermogravimetric analysis shows that decomposition processes are multistage, and dehydration is the first step of decomposition. Moreover, TG–DTG–DSC analyses indicate that the thermal stability and the decomposition path of tested compounds depend on the DS. Results of Py–GC/MS studies showed that the formation of decomposition products (including cyclic and aromatic hydrocarbons) in a predetermined temperature range is lower in the case of CMS–Na with high DS.
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ARAÚJO, Eliane Gonçalves, and Nedja Suely FERNANDES. "EVALUATION THERMOANALYTICAL OF WHEAT FLOUR FORTIFIED WITH FOLIC ACID AND FERROUS SULPHATE." Periódico Tchê Química 06, no. 12 (August 20, 2009): 47–50. http://dx.doi.org/10.52571/ptq.v6.n12.2009.48_periodico12_pgs_47_50.pdf.
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In this work wheat flour aditived with folic acid and iron sulphate was evaluated by Thermogravimetry (TG), Derivative Thermogravimetry (DTG) and differential scanning calorimetry (DSC) for evaluation of the thermal stability. The results obtained showed that the samples of wheat flour have similar behaviour.
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Kijo-Kleczkowska, Agnieszka, Adam Gnatowski, Magdalena Szumera, Henryk Otwinowski, Dariusz Kwiatkowski, and Łukasz Suchecki. "Effect of addition of coal sludge to polymeric material on thermal effects in analysis by TG/DTG/DSC methods." E3S Web of Conferences 154 (2020): 03002. http://dx.doi.org/10.1051/e3sconf/202015403002.
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The paper presents the application of thermal analysis methods in the study of various materials: coal sludge, polymeric material and composites of a polymer with coal sludge (fraction of coal sludge in composites: 1%, 3% and 5%). TG/DTG/DSC curves obtained during measurements in air atmosphere were analyzed. Polymers are used in many industries, that is why their thermal characteristics are so important. On the other hand, the mining industry, forced to supply power plants better quality fuel, must perform more thorough coal cleaning. This results in a continuous increase in waste in the form of coal sludge. The best method of disposing of these wastes is thermal utilisation (combustion and co-combustion), as well as use in composites with other materials. The aim of the study was to demonstrate the effect of the addition of coal sludge to the polymer on the energetic effect and the rate of mass change of the material sample during the thermal process by TG/DTG/DSC methods.
Dissertations / Theses on the topic "TG/DTG and DSC"
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Pereira, Thereza Mylene de Moura. "Caracteriza??o t?rmica (TG/DTG, DTA, DSC, DSC-fotovisual) de Horm?nios bioid?nticos (estriol estradiol)." Universidade Federal do Rio Grande do Norte, 2013. http://repositorio.ufrn.br:8080/jspui/handle/123456789/13478.
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Previous issue date: 2013-03-22Bioidentical hormones are defined as compounds that have exactly the same chemical and molecular structure as hormones that are produced in the human body. It is believed that the use of hormones may be safer and more effective than the non-bioidentical hormones, because binding to receptors in the organism would be similar to the endogenous hormone. Bioidentical estrogens have been used in menopausal women, as an alternative to traditional hormone replacement therapy. Thermal data of these hormones are scarce in literature. Thermal analysis comprises a group of techniques that allows evaluating the physical-chemistry properties of a drug, while the drug is subjected to a controlled temperature programming. The thermal techniques are used in pharmaceutical studies for characterization of drugs, purity determination, polymorphism identification, compatibility and evaluation of stability. This study aims to characterize the bioidentical hormones estradiol and estriol through thermal techniques TG/DTG, DTA, DSC, DSC-photovisual. By the TG curves analysis was possible to calculated kinetic parameters for the samples. The kinetic data showed that there is good correlation in the different models used. For both estradiol and estriol, was found zero order reaction, which enabled the construction of the vapor pressure curves. Data from DTA and DSC curves of melting point and purity are the same of literature, showed relation with DSC-photovisual results. The analysis DTA curves showed the fusion event had the best linearity for both hormones. In the evaluation of possible degradation products, the analysis of the infrared shows no degradation products in the solid state
Horm?nios bioid?nticos s?o compostos que t?m exatamente a mesma estrutura qu?mica e molecular dos horm?nios end?genos humanos. Acredita-se que a utiliza??o desses horm?nios pode ser mais segura e eficaz que os horm?nios n?o-bioid?nticos, pois a liga??o aos receptores no organismo se daria de forma semelhante aos horm?nios end?genos. Estrog?nios bioid?nticos v?m sendo utilizado, em mulheres na menopausa, como uma alternativa ? terapia de reposi??o hormonal tradicional. Dados t?rmicos desses horm?nios s?o escassos na literatura. A an?lise t?rmica ? um conjunto de t?cnicas que possibilita medir as propriedades f?sico-qu?micas de uma subst?ncia em fun??o da temperatura. As t?cnicas t?rmicas v?m sendo utilizadas na ?rea farmac?utica em diversas aplica??es, como na caracteriza??o de f?rmacos, determina??o do grau de pureza, identifica??o de polimorfismo, estudos de estabilidade e compatibilidade. Este trabalho tem como objetivo a caracteriza??o dos horm?nios bioid?nticos estradiol e estriol atrav?s das t?cnicas t?rmicas TG/DTG, DTA, DSC, DSC-fotovisual. A partir da an?lise das curvas TG, foi poss?vel calcular os par?metros cin?ticos para as amostras. Os dados cin?ticos mostraram boa correla??o entre os diferentes modelos empregados. Tanto para o estradiol como para o estriol, foi encontrada ordem zero de rea??o, o que possibilitou a constru??o das curvas de press?o de vapor. Dados das curvas DSC e DTA sobre ponto de fus?o e pureza s?o condizentes com a literatura, sendo poss?vel correlacionar estes resultados com o DSC-fotovisual. As an?lises das curvas DTA mostraram o evento de fus?o como o de melhor linearidade para os dois horm?nios. Na avalia??o dos poss?veis produtos de degrada??o, a an?lise do infravermelho mostra que n?o houve produtos de degrada??o no estado s?lido
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Nunes, Ronaldo Spezia. "Estudo do comportamento térmico de alguns aditivos alimentares por TG/DTG, DTA e DSC." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/75/75132/tde-25082009-161837/.
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Estudos termoanalíticos de alguns aditivos alimentares da classe dos realçadores de sabor foram desenvolvidos visando avaliar sua estabilidade e resistência durante o preparo de alimentos a quente assim como investigar os eventuais intermediários de decomposição que poderiam resultar destes processos. Os sais foram obtidos de fontes industriais ou sintetizados e submetidos à caracterização por análise elementar, espectrometria vibracional na região do infra-vermelho, termogravimetria/termogravimetria derivada, análise térmica diferencial e em alguns casos, calorimetria exploratória diferencial. Foram estudados o ácido glutâmico e seus sais de amônio, lítio e sódio mono e dissubstituídos. Em todos os casos observou-se uma conversão a piroglutamato após desidratação dos sais monossubstituídos, a qual ocorre via a a-carboxila. A estabilidade térmica destes sais foi da ordem de 190-200 °C. No caso dos sais dissubstituídos de lítio e sódio não houve conversão ao piroglutamato pois as duas carboxilas estão salificadas. Os glutamatos de magnésio, cálcio estrôncio e bário, também foram preparados e investigados quanto ao seu comportamento térmico. Os sais se formaram na estequiometria 2:1 (ligante:metal), apresentando águas de hidratação em número característico e foram estáveis até 190- 200 °C. Finalmente foram estudados os mecanismos de decomposição térmica do inosinato-monofosfato de sódio e do guanilato-monofosfato de sódio, dois nucleotídeos que apresentam a propriedade de realçar o sabor de alimentos. Ambos apresentaram elevado grau de hidratação, para o qual foi possível distinguir mecanismos característicos de desidratação. A decomposição dos sais anidros ocorreu com saída do grupo purínico, seguida da decomposição do restante da molécula e formação de pirofosfato de sódio como resíduo final.Thermal analytical studies of some food addictives of the flavor enhancer class were developed in order to evaluate their stability and resistance to the hot cooking process, as well as to identify the intermediaries of thermal decomposition that could remain at the end of such processes. The salts were obtained from industrial sources or synthesized and characterized by elemental analysis, infra-red spectroscopy, thermogravimetry/derivative thermogravimetry, differential thermal analysis and in some opportunities to differential scanning calorimetry. The glutamic acid and its ammonium, lithium and sodium salts mono and disubstituted were investigated. In all cases a conversion to pyroglutamate has been observed in the free acid and its monosubstituted salts after dehydration. The conversion undergoes by the ?-carboxyl group. The thermal stability was observed to be as high as 190-200 °C. In the case of the lithiu m and sodium dissubstituted salts any conversions to pyroglutamates were observed, once both carboxyl groups were salified. Magnesium, calcium, strontium and barium glutamates has also been synthesized and investigated in relation to its thermal behavior. The salts were formed in the 2:1 stoichiometry (ligand:metal), presenting hydration waters in a characteristic content and showed to be stable up to 190-200 °C. Finally the thermal decomposition mechanisms of dissodium inosinatemonophosphate and dissodium guanilate-monophosphate two nucleotides with flavor enhancement properties in food were also investigated. Both presented high degree of hydration, to which it was possible to propose a water release mechanism. The decomposition of the anhydrous salts occurred with release of the purine group followed by the decomposition of the rest of the molecule generating sodium pyrophosphate as residue.
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Porto, Dayanne Lopes. "Contribui??es sobre estudos t?rmicos (TG/DTG, DTA, DSC e DSC-Fotovisual) da rifampicina e seus principais produtos de degrada??o." Universidade Federal do Rio Grande do Norte, 2014. http://repositorio.ufrn.br:8080/jspui/handle/123456789/13506.
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Previous issue date: 2014-03-24Since its synthesis over 48 years rifampicin has been extensively studied. The literature reports the characterization of thermal events for rifampicin in nitrogen atmosphere, however, no characterization in synthetic air atmosphere. This paper aims to contribute to the thermal study of rifampicin through thermal (TG / DTG, DTA, DSC and DSC - FOTOVISUAL ) and non-thermal (HPLC, XRPD , IR - FTIR , PCA) and its main degradation products ( rifampicin quinone , rifampicin N-oxide 3- formylrifamicin). Rifampicin study was characterized as polymorph form II from techniques DSC, IR and XRPD. TG curves for rifampicin in synthetic air atmosphere showed higher thermal stability than those in N2, when analyzed Ti and Ea. There was characterized as overlapping events melting and recrystallization under N2 with weight loss in the TG curve, suggesting concomitant decomposition. Images DSCFotovisual showed no fusion event and showed darkening of the sample during analysis. The DTA curve in synthetic air atmosphere was visually different from DTA and DSC curves under N2, suggesting the absence of recrystallization and melting or presence only decomposition. The IV - FTIR analysis along with PCA analysis and HPLC and thermal data suggest that rifampicin for their fusion is concomitant decomposition of the sample in N2 and fusion events and recrystallization do not occur in synthetic air atmosphere. Decomposition products studied in an air atmosphere showed no melting event and presented simultaneously to the decomposition initiation of heating after process loss of water and / or solvent, varying the Ti initiating events. The Coats - Redfern , Madsudhanan , Van Krevelen and Herwitz - Mertzger kinetic parameters for samples , through the methods of OZAWA , in an atmosphere of synthetic air and / or N2 rifampicin proved more stable than its degradation products . The kinetic data showed good correlation between the different models employed. In this way we contribute to obtaining information that may assist studies of pharmaceutical compatibility and stability of substances
estudada. H? relatos de estudos focando o desenvolvimento de metodologias anal?ticas, novas aplica??es farmac?uticas, bem como, desenvolvimento de novas formas farmac?uticas. A busca pelo entendimento dascaracter?sticas f?sico-qu?micas das subst?ncias tem auxiliado no desenvolvimento de novos produtos farmac?uticos, com seguran?a, efic?cia e qualidade,fornecendo informa??es ?teis sobre s?ntese e armazenamento. Dentre os produtos de decomposi??o j? conhecidos para rifampicina, temos a rifampicina quinona, rifampicina N-?xido e 3-formilrifampicina, para tais, dados t?rmicos s?o escassos na literatura. As t?cnicas t?rmicas v?m sendo utilizadas na ?rea farmac?utica em diversas aplica??es, como na caracteriza??o de f?rmacos, determina??o do grau de pureza, identifica??o de polimorfismo, estudos de estabilidade, compatibilidade e cin?tica de degrada??o. Este trabalho tem como objetivo contribuir com o estudo t?rmico da rifampicina atrav?s das t?cnicas t?rmicas (TG/DTG, DTA, DSC, DSC-Fotovisual)e n?o t?rmicas, e seus principais produtos de degrada??o (rifampicina quinona, rifampicina N-?xido 3-formilrifamicina). A partir de an?lises DSC, DRX e FTIR foi poss?vel caracterizar a rifampicina estudada como polimorfo II. O conjunto de t?cnicas t?rmicas e n?o t?rmicas auxiliaram a verificar que parte da rifamipicina ? decomposta durante o processo de fus?o, em atmosfera de nitrog?nio, bem como que, os eventos de fus?o e recristaliza??o n?o ocorrem em atmosfera de ar sint?tico passando a amostra diretamente a decomposi??o. Os produtos de decomposi??o estudados, quando em atmosfera de ar, n?o apresentaram evento de fus?o e, apresentaram v?rios passos de decomposi??o, com a ocorr?ncia de eventos exot?rmicos e endot?rmicos. A partir de curvas TG din?micas, foi poss?vel calcular os par?metros cin?ticos para as amostras, atrav?s dos m?todos de OZAWA, Coats-Redfern, Madsudhanan, Van Krevelen e Herwitz-Mertzger, em atmosfera de ar sint?tico e/ou nitrog?nio. Os dados cin?ticos mostraram boa correla??o entre os diferentes modelos empregados. Tanto para rifampicina quanto os produtos de degrada??o estudados, foi caracterizado rea??o de ordem um
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Ramos, Luiz Antonio. "Investigação do comportamento térmico e de polimorfismo do anti-histamínico loratadina." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/75/75132/tde-04082011-143805/.
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O comportamento térmico, a obtenção e caracterização de formas cristalinas do anti-histamínico loratadina foram investigado. A escolha do anti-histamínico loratadina como objeto de estudo resulta do seu interesse farmacológico. A loratadina é a Denominação Comum Internacional (DCI) dada ao etil 4-(8-cloro-5,6-dihidro-11H-benzo[5,6]cicloheptano[1,2-b]piridino-11-ilideno)-1-piperidinocarboxilato, que é um potente antialérgico e anti-histamínicos tricíclico, não-sedativo de ação prolongada. Formas cristalinas foram preparadas e estudadas com vista à identificação de formas polimórficas. Os solventes utilizados na preparação das soluções foram: álcool etílico, acetonitrila, álcool isopropílico, acetona, álcool metílico, éter isopropílico, éter metil terc-butílico, tolueno, clorofórmio. A cristalização foi realizada por evaporação do solvente em diferentes temperaturas. A calorimetria exploratória diferencial (DSC), termogravimetria e termogravimetria derivada (TG/DTG), análise térmica diferencial (DTA), difração de raios X (DRX) e a ressonância magnética nuclear (RMN) foram às técnicas utilizadas na caracterização das formas polimórficas. A maioria das amostras obtidas pelas técnicas de cristalização consistiam de misturas de formas cristalinas, contendo, por vezes, formas metaestáveis e formas amorfas. Identificaram-se duas formas cristalinas como polimorfos da loratadina, cujas curvas DSC mostrou interconversão entre ambas.The preparation, characterization and thermal behavior of the crystalline forms of the antihistamine loratadine has been developed. The selection of loratadine as an object of study results from its pharmacological interest. Loratadine is the International Common Denomination (ICD) given to ethyl 4-(8-chloro-5,6-dihydro-11H-benzo [5,6] cyclohepta[1,2-b]pyridin-11-ylidene)-1-piperidinecarboxylate, a potent anti-allergic and anti-histamincs, tricyclic, non-sedating long acting. Crystalline forms were prepared and studied for the identification of polymorphic forms. The solvents used in preparing the solutions were: ethanol, acetonitrile, isopropyl alcohol, acetone, methyl alcohol, isopropyl ether, methyl tert-butyl ether, toluene, chloroform. The crystallization was performed by evaporating the solvent at different temperatures. The differential scanning calorimetry (DSC), thermogravimetry and derivative thermogravimetry (TG/DTG), differential thermal analysis (DTA), X-ray diffraction (XRD) and nuclear magnetic resonance (NMR) techniques were used to characterize the polymorphic forms. Most of the samples obtained by the crystallization were mixtures of crystalline forms, containing sometimes forms metastable and amorphous forms. It was identified as two crystalline polymorphic forms of loratadine, whose DSC curves demonstrated that they are interconvertable.
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Oliveira, Floripes Ferreira de. "Contribuição da análise térmica no desenvolvimento de formulações de batons." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/46/46133/tde-02122015-141614/.
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Este trabalho consiste na caracterização química, física e termoanalítica de algumas amostras de batons e dos componentes de suas formulações. O estudo termoanalítico foi desenvolvido a partir das técnicas TG/OTG sob atmosfera dinâmica de ar ou enriquecida com O2 e por DSC sob atmosfera dinâmica de N2, com razão de aquecimento de 10°C min-1 em ambos os casos. Os testes de estabilidade com exposição das amostras a 4, 25 e 43°C e à luz solar indireta permitiram avaliar as propriedades organolépticas, físicas e térmicas. Os resultados da análise de ponto de fusão obtidos pelo método convencional foram comparados àqueles encontrados por ensaios de DSC. A estabilidade térmica foi determinada pela exposição a 43°C em estufa convencional e a partir da técnica de TG no estudo da cinética de decomposição, utilizando-se os métodos dinâmico e isotérmico. Foi realizada a predição do prazo de validade de 2,4 anos para uma amostra específica de batom foi determinada por meio do estudo cinético pelo método isotérmico, aplicando-se a equação de Arrhenius. A performance de três diferentes antioxidantes quanto à estabilidade térmica de uma amostra de batom foi avaliada, verificando-se, melhor comportamento da mistura de tocoferáis aplicada a 1%.This work consists of the chemical, physical and thermoanalytical characterization of some samples of lipsticks and the components of their formulation. The thermoanalytical study was developed by means of TG/DTG techniques under dynamic air atmosphere or air enriched with O2 and by DSC in dynamic nitrogen atmosphere, with heating rate of 10°C min-1 in both cases. The stability tests with the submitled samples at 4, 25, 43°C and sunlight allowed to evaluate the organoleptic, physical and thermal properties. The analytical results of melting point obtained from conventional methods were compared to the ones measured by DSC. The thermal stability was determined by exposition at 43°C in a conventional stove and by TG technique in the study of decomposition\'s kinetic, using dynamic and isothermal methods. A shelf-life prediction of 2.4 years for a specific sample of Iipstick was determined by means of a kinetic study, using an isothermal method and applying Arrhenius\' equation. The performance of three different antioxidants concerning the thermal stability of a Iipstick sample was evaluated, the tocopherol mix showed the better performance when applied at 1%.
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Neres, Renata Aparecida. "Caracterização térmica de amostras de esponja sintética dupla face e palha de aço." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/46/46136/tde-23012015-100142/.
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Este trabalho tem por objetivo a caracterização comparativa do comportamento de degradação e/ou decomposição térmica da esponja sintética dupla face, base poliuretana (parte amarela e parte verde), e da palha de aço, a partir das técnicas termoanalíticas. As esponjas sintéticas para limpeza doméstica, em substituição à palha de aço, apesar da vantagem econômica, podem apresentar restrições de descartes para o meio ambiente ou expor o usuário a riscos de contaminação. Amostras de esponja sintética dupla face (verde e amarela) e de palha de aço foram caracterizadas por análise térmica (TG/DTG, DTA e DSC) empregando atmosfera dinâmica de ar e de N2. Essas amostras foram estudadas por métodos cinéticos por termogravimetria isotérmica e não isotérmica. Os parâmetros cinéticos obtidos permitiram estimar os tempos necessários para a decomposição de ambas as partes da amostra da esponja sintética e também da palha de aço sob atmosfera de ar. Os resultados evidenciaram claramente que a matriz polimétrica da esponja sintética para ser degradada completamente exige um tempo muito longo, acima de 20.000 anos. Por outro lado, os resultados indicaram comportamento similar entre as amostras de esponja sintética e de palha de aço considerando apenas o efeito temperatura e tipo de atmosfera. Contudo, no cotidiano sabe-se que a palha de aço se oxida muito facilmente sob atmosfera de ar na presença de umidade.This work aims at a comparative characterization of degradation behavior and/or thermal decomposition of synthetic double-face sponge, polyurethane base (yellow part and green part), and steel wool, from thermoanalytical techniques. Synthetic sponges for household cleaning, replacing steel wool, despite the economic advantage, may have restrictions on discharges to the environment or expose the user to risks of contamination. Samples dual synthetic sponge face (green and yellow) and steel wool were characterized by thermal analysis (TG/DTG and DTA DSC) employing an atmosphere of air and N2. These samples were studied by kinetic methods isothermal and non-isothermal thermogravimetric analysis. The kinetic parameters obtained allowed the estimation necessary for decomposition of the sample both sides of the synthetic spomge and also of steel straw times under air atmosphere. The results clearly showed that polymetric matrix of synthetic sponge to be degraded completely requires a very long time, over 20,000 years. Moreover, the results showed similar behavior among synthetic sponge and steel wool sample considering only the effect of temperature and type of atmosphere. However, in daily life it is known that the steel wool oxidizes very easily under air atmosphere in the presence of moisture.
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Martins, Tercio Elyan Azevêdo. "Desenvolvimento, caracterização e avaliação da formação de complexos de inclusão de rutina, avobenzona e ρ-metoxicinamato de octila na presença de ciclodextrinas." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/9/9139/tde-05092018-104724/.
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A radiação UV pode causar danos à pele humana, e, evitar estes danos, é uma preocupação crescente para a população e um desafio à comunidade científica. Para uma ação efetiva de fotoproteção, a associação de filtros, como avobenzona (BMBM) e ρ-metoxicinamato de octila (EHMC), são empregados. Devido à semelhança estrutural com os filtros solares químicos, a rutina (RUT), tal como outros flavonoides, apresenta atividade fotoprotetora. Apesar da disponibilidade de diferentes classes de filtros solares, o desenvolvimento de fotoprotetores contendo filtros químicos é um desafio, devido à instabilidade inerente a certos filtros orgânicos. As ciclodextrinas (CDs) são oligossacarídeos cíclicos, de formato tronco-cônico, cuja estrutura externa é hidrófilica e sua cavidade interna central hidrofóbica, com a capacidade de acomodar substâncias lipofílicas, formando complexos de inclusão. A formação dos complexos de inclusão pode levar à alterações de propriedades físico-químicas da molécula hóspede, tais como, solubilidade, fotoestabilidade e biodisponibilidade. O objetivo deste trabalho foi desenvolver, caracterizar e avaliar a formação de complexos de inclusão entre RUT, BMBM e EHMC e as CDs (HPβCD e SBEβCD). Os complexos de inclusão (RUT:HPβCD, RUT:SBEβCD, BMBM:HPβCD, BMBM:SBEβCD, EHMC:HPβCD e EHMC:SBEβCD) foram obtidos pelo método de liofilização e quantificados por cromatografia líquida de alta eficiência (CLAE). Os sistemas binários foram caracterizados em solução, pelo método de equilíbrio de solubilidade, e, no estado sólido, empregando calorimetria exploratória diferencial (DSC), termogravimetria (TG/DTG) e difração de raios-X de pó (PDRX). As substâncias isoladas e os complexos binários foram avaliados quanto à fotoestabilidade em estado sólido, e, em solução. Incremento na solubilidade (X mcg mL-1) foi observado para os complexo RUT:HPβCD (4,13x); RUT:SBEβCD (4,38x); BMBM:HPβCD (43,3x); BMBM:SBEβCD (53,3x); EHMC:HPβCD (12,7x); e EHMC:SBEβCD (70,0x). Os ensaios de DSC, TG/DTG, e P-DRX indicaram a formação de complexos de inclusão para os todos os sistemas, onde a supressão dos eventos endotérmicos característicos das substâncias isoladas foram observados; porém, nos complexos de BMBM, a presença de avobenzona livre no meio foi detectada, sugerindo, que a complexação não foi completa. A formação dos complexos de inclusão promoveu o aumento da fotoestabilidade em todos os sistemas avaliados, tanto no estado sólido, como em solução. Os resultados reportados neste estudo, indicaram que a complexação de substâncias fotoprotetoras com HPβCD e SBEβCD, pode representar, uma estratégia promissora quanto ao aumento da solubilidade e da fotoestabilidade.UV radiation may cause demage on human skin, and preventing it, is an increasing worry for the population and a challenge to the scientific community. For an effective action of photoprotection, the association of filters, like avobention (BMBM) and octyl ρ-methoxycinnamate (EHMC), are used. Due to the structural similarity with the chemical solar filters, the rutin (RUT), like other flavonoids, shows photoprotective activity. Despite the availability of different classes of sunscreens, the development of photoprotectors containing chemical filters is a challenge, due to the inherent instability of certain organic filters. The cyclodextrins (CD) are cyclic oligosaccharides of truncated conical structure, which external structure is hydrophilic and its internal central hydrophobic cavity, with capacity to accommodate lipophilic substances, forming inclusion complexes. The formation of the inclusion complexes can lead to changes in physicalchemical properties of the host molecule, such as, solubility, photostability and bioavailability. The objective of this work was to develop, characterize and evaluate the formation of the inclusion complexes between RUT, BMBM and EHMC and the CDs (HPβCD and SBEβCD). The inclusion complexes (RUT:HPβCD, RUT:SBEβCD, BMBM:HPβCD, BMBM:SBEβCD, EHMC:HPβCD and EHMC:SBEβCD) were obtained by the lyophilization method and quantified by high performance liquid chromatography (HPLC). The binary systems were characterized in solution, by solubility equilibrium method and in solid state, using differential scanning calorimetry (DSC), thermogravimetry (TG/DTG) and powder X-ray diffraction (P-XRD). The isolated substances and binary complexes were evaluated the photostability in solid state, and in solution. The increase in solubility (X mcg mL-1) was observed for the complexes RUT:HPβCD (4.13x); RUT:SBEβCD (4.38x); BMBM:HPβCD (43.3x); BMBM:SBEβCD (53.3x); EHMC:HPβCD (12.7x); and EHMC:SBEβCD (70.0x). The analysis of DSC, TG/DTG, and P-DRX indicated the formation of inclusion complexes for all systems, where the suppression of the endothermic events characteristic of the isolated substances were observed; however, in the BMBM complexes, the presence of free avobenzone was detected, suggesting that the complexation was not complete. The formation of inclusion complexes promoted the increase of photostability in all evaluated systems, as in solid state as in solution. The results reported in this study indicated that the complexation of photoprotective substances with (HPβCD e SBEβCD). may represent a promising strategy for increasing solubility and photostability.
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Koreeda, Tamy. "Caracterização termoanalítica e estudo de cura de compósito de resina epóxi e mica com propriedades elétricas isolantes aplicado em máquinas hidrogeradoras." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/46/46133/tde-25042011-112216/.
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Atualmente, a participação da energia elétrica na matriz energética mundial é um assunto em evidência. O estudo do compósito isolante da barra estatórica, um dos componentes principais da máquina hidrogeradora, permite a obtenção de informações físico-químicas relevantes ao aperfeiçoamento do sistema, e também de estudos de comportamento térmico quando este é exposto à alta temperatura, por diferentes intervalos de tempo submetidos a estresses mecânicos, elétricos e/ou químicos. O sistema em estudo é o MICALASTIC®, desenvolvido pela empresa Siemens em 1960. Neste trabalho, as propriedades térmicas do compósito isolante, formado por uma fita de mica, resina epóxi (DGEBA), endurecedor (MHHPA) e acelerador naftenato de zinco (N-Zn) foram estudadas. Utilizando-se as técnicas termoanalíticas Calorimetria Exploratória Diferencial (DSC) e Termogravimetria e Termogravimetria Derivada (TG/DTG), o comportamento térmico de cada um dos materiais foi avaliado. As curvas DSC e TG/DTG também evidenciaram as possíveis interações químicas entre os componentes. Os estudos referentes à cura do material e da degradação térmica do compósito curado foram realizados. Observou-se claramente a influência da quantidade de acelerador na polimerização do sistema. A partir das curvas DSC, observou-se dois mecanismos de cura diferentes coexistentes, um com menor quantidade de N-Zn e outro com concentração maior, resultando em eventos de cura com início em temperaturas diferentes. Esse fato ainda não havia sido estudado desde a origem do sistema. Além disso, a perda de massa referente à evaporação do endurecedor no início do processo de cura foi confirmada a partir da caracterização do compósito por espectroscopia de absorção na região do infravermelho, comparando-se os espectros antes e após o fenômeno. Na prática, dois perfis de impregnação, o Homogêneo e o Heterogêneo, de barras condutoras são utilizados, e uma diferença significativa entre eles foi observada. Os estudos desenvolvidos devem ser associados a testes elétricos específicos para o melhor entendimento da relação entre a aplicação do material e suas propriedades teóricas termoanalíticas. Além disso, foi realizado o estudo cinético da decomposição térmica do compósito curado por métodos termogravimétricos, isotérmico e dinâmico.Currently, the electric energy participation in the world energy matrix is a significant issue. The insulating composite in stator bars, which are one of the most important components in hydrogenerator machines, allows the attainment of relevant physical and chemical information to system optimization, in addition to study thermal behavior when the material is exposed to high temperatures, for different time intervals and mechanical, chemical and/or electrical stress. The studied system is MICALASTIC®, developed by Siemens Company in 1960. In this work, thermal properties of this insulating composite, composed by mica tape, epoxy resin (DGEBA), hardener (MHHPA) and zinc naphtenate (N-Zn) as accelerator, were studied. Using thermoananalytical techniques as Differential Scanning Calorimetry (DSC) and Thermogravimetry and Derivative Thermogravimetry (TG/DTG), thermal behavior of each material was evaluated. DSC and TG/DTG curves evidenced chemical interactions between components. The study relative to material curing and cured composite thermal degradation were described. It was clearly observed the N-Zn amount influence in the cure of system, and through DSC curves, it was possible to observe two distinct polymerization coexisting mechanisms, one with lower quantity of N-Zn and another one with bigger concentration, resulting in cure events starting in different temperatures. This fact has not been studied yet since the system has been originated. Besides that, the weight loss related to hardener evaporation starting with curing process was confirmed by composite characterization by FTIR spectra, before and after phenomenon. In practice, two impregnation patterns (Homogeneous and Heterogeneous) of conductive bars are used and a significant difference between them was observed. The developed studies have to be associated to electrical tests to a best understanding about material application and theoretical thermoanalytical properties. In addition, it was performed thermal decomposition of cured composite kinetic study by isothermic and dynamic thermogravimetric methods
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Siqueira, Geisa Liandra de Andrade de. "EFEITO DO TRATAMENTO ÁCIDO EM MEIO AQUOSO E ALCOÓLICO NA MODIFICAÇÃO DO AMIDO DE PINHÃO (Araucaria angustifolia)." Universidade Estadual de Ponta Grossa, 2017. http://tede2.uepg.br/jspui/handle/prefix/2667.
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Araucaria angustifolia (Bert.) O. Kuntze é uma conífera presente nas florestas brasileiras e as suas sementes apresentam alto teor de amido. Os pinhões utilizados nesta pesquisa foram provenientes de materiais genéticos e selecionados com base em testes preliminares por apresentarem temperatura de gelatinização inferior a 60ºC. Esta é considerada uma característica interessante e vantajosa, podendo economizar tempo e energia durante o processo de gelatinização do amido. O amido na sua forma natural apresenta limitações, portanto uma das alternativas é a hidrólise ácida que tem o intuito de alterar as suas propriedades físico-químicas. Este tratamento aliado a solução alcoólica apresenta a capacidade de recuperar grande parte do grânulo. O objetivo deste estudo foi identificar os efeitos da modificação ácida em meio aquoso e alcoólico de amidos de pinhão (A. angustifolia) com temperaturas de gelatinização abaixo de 60 ºC. As amostras foram avaliadas quanto ao pH e Colorimetria, por análise térmica (TG-DTA e DSC), pelo comportamento reológico (RVA), por análises estruturais (DRX e MEV) e por análises estatísticas (ANOVA e Tukey). A recuperação do grânulo de amido foi maior no meio aquoso e no meio alcoólico os valores ficaram próximos a 90% de recuperação. Os valores de pH comprovaram que o processo eliminou o ácido utilizado na modificação e a colorimetria identificou a coloração branca e levemente amarela para ambos os acessos, mostrando que os tratamentos não alteraram as características colorimétricas dos amidos de pinhão. Nas curvas TGDTA em ar sintético foram observadas três perdas de massa. As amostras nativas apresentaram diferença no DTA e as temperaturas finais demonstraram maior resistência térmica dos amidos. Nas curvas TG-DTA em nitrogênio foram encontradas duas perdas de massa. As amostras tratadas apresentaram semelhança no DTA e as temperaturas finais não foram alteradas devido à atmosfera inerte. Na análise de DSC, a Tc e a ∆Hgel não apresentaram diferenças significativas, apenas no To e Tp. Os tratamentos mais intensos mostraram leve resistência térmica e menor ∆Hgel. No RVA foi observado redução nos parâmetros de viscosidade conforme a intensidade do tratamento. O DRX identificou o padrão do tipo C para os amidos e a cristalinidade relativa aumentou conforme a intensidade da hidrólise ácida. Pelo MEV foram observadas alterações superficiais nos grânulos. Diante dos resultados encontrados, os amidos de pinhão demonstraram ser promissores para aplicações industriais visando specialties, ou seja, para produtos com escala reduzida. O intuito é estimular os pequenos produtores, proporcionar agregação de valor ao produto final e a manutenção da espécie A. angustifolia.
Araucaria angustifolia (Bert.) O. Kuntze is a conifer present in Brazilian forests and its seeds are high in starch. The pinhões used in this research were derived from genetic material and selected based on preliminary tests because they presented a gelatinization temperature below the 60 ºC. This is considered an interesting and advantageous feature, which can save time and energy during the starch gelatinization process. Starch in its natural form has limitations, so one of the alternatives is acid hydrolysis, which has the purpose of altering its physicochemical properties. This treatment combined with alcoholic solution has the ability to recover majority of the granule. The aim of this study was to identify the effects of acidic modification on aqueous and alcoholic solutions of pinhão starches (A. angustifolia) with gelatinization temperatures below of 60 ºC. The samples were evaluated for pH and Colorimetry by thermal analysis (TG-DTA e DSC), by rheological behavior (RVA), by structural analysis (XRD and SEM) and by statistical analysis (ANOVA and Tukey). The recovery of the starch granule was higher in the aqueous medium and in the alcoholic solution; the values were close to 90% recovery. The pH values showed that the process eliminated the acid used in the modification and the Colorimetry identified the white and slightly yellow coloration for both accessions, showing that the treatments did not alter the colorimetric characteristics of the pinhão starches. In the TG-DTA curves in synthetic air, three mass losses were observed. The native samples presented a difference in the DTA and the final temperatures showed a higher thermal resistance of the starches. In the TG-DTA curves in nitrogen, two mass losses were found. The treated samples showed similarity in DTA and the final temperatures were not changed due to the inert atmosphere. In the DSC analysis, Tc and ΔHgel did not show significant differences, only in To and Tp. The most intense treatments showed light thermal resistance and lower ΔHgel. In the RVA, a reduction in the viscosity parameters was observed according to the intensity of the treatment. XRD identified the type C pattern for starches and relative crystallinity increased as the acid hydrolysis rate increased. Superficial changes in the granules were observed by SEM. Considering the results found, the pinhão starches demonstrated to be promising for industrial applications aiming specialties, that is, for products with reduced scale. The intention is to stimulate small producers, provide benefits to the final product and the maintenance of the species A. angustifolia.
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Davila, Felipe Jaime. "Formación tardía de etringita en fibrocemento." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/3/3146/tde-07072016-103228/.
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La temperatura de curado, utilizada por la industria de fibrocemento como catalizador en la hidratación del cemento para lograr alta resistencia inicial en sus productos, genera la hipótesis de expansión causada por formación tardía de etringita. Para el planteamiento de dicha hipótesis, el siguiente estudio contempló dos grupos de muestras con el objetivo de estudiar aisladamente su comportamiento químico y físico: uno de los grupos conformado por pasta cementicia con 35% de sustitución de calcario, y el otro conformado por fibrocemento con incorporación de PVA y celulosa. Por calorimetría isotérmica se observó la cinética de reacción de dos pastas, una de ellas curada a 23 ºC y la otra a 85 ºC donde esta última experimentó un efecto catalizador en sus reacciones. Ensayos de DRX y DTG/TG mostraron la presencia de etringita a 23 °C durante todas las edades de hidratación exhibiendo una tendencia de aumento en la intensidad de los picos y en la cantidad, respectivamente, en función del tiempo; sin embargo, a 85 ºC la presencia de esta fase fue inconstante durante las primeras edades de hidratación, a partir de mes de hidratación mostró aumento en cada una de las siguientes medidas realizadas mensualmente; a 85 °C hubo una menor formación de portlandita en comparación con los resultados obtenidos a 23 °C. Utilizando el método Rietveld y análisis químico fueron determinadas las cantidades y las composiciones químicas, respectivamente, de las fases del cemento anhidro y del calcario para alimentar el programa GEMS y simular la hidratación de la pasta estudiada en laboratorio para un tiempo infinito bajo la influencia de la temperatura. Simulaciones de la hidratación de la pasta se aproximaron a los resultados reportados por la revisión bibliográfica permitiendo predecir la presencia de fases en función de la estabilidad termodinámica. Resultados de porosimetría por inyección de mercurio mostraron una mayor concentración de poros, asociados a defectos, en muestras curadas a 85°C con respecto a las de 23 °C. Finalmente, medidas de variación longitudinal para muestras de fibrocemento elaboradas en laboratorio y en fábrica presentaron dispersión en los resultados de expansión para cada uno de los escenarios sin poder correlacionar todos los datos con el aumento de masa exhibido por cada una de las muestras; no obstante, se resalta el riesgo de deterioro del fibrocemento por el aumento de defectos causado por la temperatura así como la creación de todas las condiciones necesarias que favorecen la formación tardía de etringita a partir del proceso de fabricación empleado para este producto.The curing temperature using by the fibercement industry as a catalyst in the hydration of cement, hypothesizes expansion caused by delayed ettringite formation. To approach this hypothesis, this study looked at two groups of samples in order to study its chemical and physical behavior individually. One group was composed of cement paste with 35% substitution of limestone filler, and the other by fibercement with addition of PVA and cellulose. In the isothermal calorimetry test was observed the kinetics reaction of both pastes, one cured at 23 °C and the other at 85 °C, the latter showed a catalytic effect in his reactions. XRD and DTG/TG showed the presence of ettringite at 23 °C for all hydration ages exhibiting a trend of increase in the peak intensity and amount, respectively in function of time, however, at 85 °C the presence of this phase was unstable during early ages of hydration until completing one month hydration where showed an increase in each of the following measurements monthly performed. At 85 °C there was a lower formation of portlandite when it was compared with results obtained at 23 °C. Using the Rietveld quantitative method analysis and chemical analysis were determined amounts and chemical compositions, respectively, of the phases of cement anhydrous and limestone filler to feed the GEMS software and simulate the hydration of paste studied in the laboratory for an infinite time under the influence of temperature. Simulations of paste hydration approached the reported data in literature allowing predicting the presence of phases according to thermodynamic stability. Additionally, results of mercury intrusion porosimetry showed a higher concentration of pores associated with defects, in samples cured at 85 ° C compared to 23 °. Finally, were taken measures of length offset of fibercement samples produced in laboratory and factory which had incorporation of PVA fibers and cellulose; they presented dispersion in the results of expansion for each of the scenarios unable to correlate with the mass gain exhibited by each sample. However, the risk of deterioration of the fibercement is highlighted by the increase of defects caused by temperature and the creation of all necessary conditions to favor the late formation of ettringite from the manufacturing process used for this product.
Book chapters on the topic "TG/DTG and DSC"
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Liu, Hui, Liang Liu, Guowei Xiahou, Cuizhen Zhang, Luping Li, Xunhua Cen, Zhou Li, and Jieming Zhou. "Study on the Kinetics of Barks of Trees Pyrolysis by TG/DTG Analysis." In Challenges of Power Engineering and Environment, 1148–51. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-76694-0_213.
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Gentile, M., P. Xiao, and T. Abram. "XRD and TG-DSC Analysis of the Silicon Carbide-Palladium Reaction." In Ceramic Engineering and Science Proceedings, 273–81. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2013. http://dx.doi.org/10.1002/9781118807743.ch24.
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Zou, Zheng, Yuesheng Fan, Zidong Cao, Xiaoke Jiang, and Yingchao Xu. "Study on Combustion Characteristics of Pulverized Coal under High Oxygen Concentration by TG-DSC." In Challenges of Power Engineering and Environment, 191–95. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-76694-0_35.
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Almeida, Luis Eduardo Nunes, Aureomar F. Martins, Susane R. Gomes, and Flavio A. L. Cunha. "Thermal Decomposition Kinetics Studies of HTPB/Al/AP Solid Propellants Formulated With Iron Oxide Burning Rate Catalyst in Nano and Micro Scale." In Energetic Materials Research, Applications, and New Technologies, 211–33. IGI Global, 2018. http://dx.doi.org/10.4018/978-1-5225-2903-3.ch010.
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The thermal decomposition kinetics of ammonium perchlorate (AP)/hydroxyl-terminated-polybutadiene (HTPB) samples, with Iron Oxide catalyst at nano and micro scale were studied by thermal analysis techniques at different heating rates in dynamic nitrogen atmosphere. The exothermic reaction kinetics was studied by differential scanning calorimetry (DSC) in isothermal conditions. The Arrhenius kinetic parameters were obtained by Flynn-Wall and Ozawa Kissinger and Starink methods. The propellant samples thermal decomposition was studied simultaneously by TG-DTA. For this purpose, solid propellant grains containing nano and micro scale iron oxide were formulated. The effect of catalysts on the propellant burning rate and the propellant initiation sensitivity were also evaluated by friction and impact. The effect of the catalyst in the propellant binder reaction was evaluated by viscosity and mechanical properties. SEM/EDS technique was used to evaluate the iron oxide morphology. Three bench firing tests were performed with rockets motor in order to know the ballistics parameters.
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Hatakeyama, Hyoe, Hitoshi Katsurada, Nobuhide Takahashi, Shigeo Hirose, and Tatsuko Hatakeyama. "DSC AND TG STUDIES ON CELLULOSE-BASED POLYCAPROLACTONES." In Recent Advances in Environmentally Compatible Polymers, 281–88. Elsevier, 2001. http://dx.doi.org/10.1533/9781845693749.5.281.
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Han, Chang Dae. "Rheology of Miscible Polymer Blends." In Rheology and Processing of Polymeric Materials: Volume 1: Polymer Rheology. Oxford University Press, 2007. http://dx.doi.org/10.1093/oso/9780195187823.003.0013.
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Broadly classified, there are three types of polymer blends, namely, (1) miscible polymer blends, (2) immiscible polymer blends, and (3) partially miscible polymer blends. There are many different experimental methods that can be used to investigate the miscibility of polymer blends, such as differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), dielectric measurement, cloud point measurement, microscopy, light scattering, small-angle X-ray scattering, small-angle neutron scattering, fluorescence technique, and nuclear magnetic resonance (NMR) spectroscopy. Each of these experimental methods can only probe the homogeneity (or heterogeneity) in a polymer blend at a certain scale range. Thus, the determination of the miscibility in polymer blends depends on the resolution limit of the experimental method(s) employed. For instance, DSC and DMTA have frequently been used to determine the miscibility in polymer blends by determining glass transition temperature Tg. When a single Tg value is observed in a polymer blend, the blend can be considered miscible. However, there is a general consensus among researchers that such an experimental criterion, while very useful, cannot guarantee that a polymer blend is miscible on a segmental level. Therefore, a serious question may be raised as to whether a polymer pair can be regarded as being miscible on the segmental level (say, less than approximately 5 nm). It has been reported that DMTA can resolve the size of domains (or separated phases) on the order of 5–10 nm (Molnar and Eisenberg 1992) and DSC is not as sensitive as DMTA for determining the Tg of a polymer blend (Stoelting et al. 1970). In the use of DSC to investigate the miscibility of polymer blends, one often encounters the situation where a very broad (say, 40–60 ◦C) single glass transition appears for certain blend compositions, such as polystyrene/poly(α-methyl styrene) (PS/PαMS) blends (Kim et al. 1998; Lin and Roe 1988; Saeki 1983) and polystyrene/poly(vinyl methyl ether) (PS/PVME) blends (Kim et al. 1998; Schneider and Wirbser 1990; Schneider et al. 1990). Under such circumstances, it is not clear how an unambiguous, single value of Tg can be read off from a DSC thermogram.
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Chen, Lei, Chunyuan Ma, and Zhanlong Song. "TG-DTG analysis and kinetics study on pyrolysis of energy crop and traditional biomass." In Advances in Energy Equipment Science and Engineering, 237–40. CRC Press, 2015. http://dx.doi.org/10.1201/b19126-49.
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Peng, Wei, Qi-lin He, and Xin-yu Ge. "Experimental studies on oxidation pattern of coal by TG-DSC-GC technology." In Mine Safety and Efficient Exploitation Facing Challenges of the 21st Century, 215–20. CRC Press, 2010. http://dx.doi.org/10.1201/b11761-31.
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Flego, C., L. Galasso, I. Kiricsi, and M. G. Clerici. "TG-DSC, UV-VIS-IR Studies on Catalysts Deactivated in Alkylation of Isobutane with 1-Butene." In Catalyst Deactivation 1994, Proceedings of the 6th International Symposium, 585–90. Elsevier, 1994. http://dx.doi.org/10.1016/s0167-2991(08)62792-5.
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Binda, Ricardo Viera, Roberta Jachura Rocha, and Luiz Eduardo Nunes Almeida. "Study of Factors Influencing the Life Predictions of Solid Rocket Motor." In Energetic Materials Research, Applications, and New Technologies, 234–45. IGI Global, 2018. http://dx.doi.org/10.4018/978-1-5225-2903-3.ch011.
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Storage of rocket motors loaded with composite solid propellant for long periods may change the propellant properties, thus causing failure and affecting the safety during launch. In this study, an accelerated aging assay was carried out, in order to predict the useful lifetime and to evaluate variations on the propellant properties with time by means of thermal analysis (TG/DSC). The aging temperatures used were 65°C, and samples were withdrawn after 3 months. Aging was also carried out at room temperature. There was significant variation in the activation energy of the solid propellant samples thermal decomposition in the two kinetic methods used – Ozawa or model-free isoconversional method and Kissinger method – during the aging period. There was significant decrease of enthalpy of aged propellant enthalpy causing changes in ballistics parameters of the solid propellant grain affecting the rocket's performance.
Conference papers on the topic "TG/DTG and DSC"
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MAIA, Yanne Fernandes, Antônio Alex de Lima SILVA, Luiz Di SOUZA, Ana Cláudia de Melo Caldas BATISTA, and Daniel Freitas Freire MARTINS. "Estudo da Estabilidade Térmica de Pneumáticos através da TG, DTG e DSC." In 5º Encontro Regional de Química & 4º Encontro Nacional de Química. São Paulo: Editora Edgard Blücher, 2015. http://dx.doi.org/10.5151/chenpro-5erq-eng8.
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Melane, Chris, Hein Badenhorst, Luxolo Holo, Eino Vuroinen, Brian Rand, and Walter W. Focke. "Oxidative Stability of Carbon by Thermal Gravimetric Analysis." In ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61423.
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The Pebble Bed Modular Reactor (PBMR) is a High Temperature Gas Cooled nuclear Reactor (HTGR) with numerous inherent passive safety features. Graphite is the most important material of construction for the reactor core and the fuel pebbles. PBMR accident scenarios include uncontrolled air ingress into the reactor. Understanding the high temperature behavior of the graphite materials under such conditions is vital for design and accident modeling purposes [1]. Graphitic materials have a very high thermal stability compared to ordinary organics. The high degradation temperatures are beyond the capability of Differential Scanning Calorimetry (DSC) and thus necessitate the use of Differential Thermal Analysis (DTA) or Thermogravimetric Analysis (TG). The oxidative stability of two graphite samples was investigated using temperature scanning TG. It was found that air oxidation of a natural graphite sample commenced at temperatures that were significantly lower than those observed for a synthetic graphite sample. The natural graphite also showed peculiar bimodal mass loss rates.
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Hu, Wenbin, Hairui Yang, Junfu Lu, Hai Zhang, Jiansheng Zhang, Qing Liu, and Guangxi Yue. "Determination of Ignition Temperature of Coal by Using Thermogravimetry." In 18th International Conference on Fluidized Bed Combustion. ASMEDC, 2005. http://dx.doi.org/10.1115/fbc2005-78135.
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In this paper, the ignition temperatures (Ti) of seven kinds of coals were measured by using thermlgravimetric analyzer (TGA). A TG-DTG method was suggested to determine the ignition temperature. This method is simple, convenient, standardized and with high repeatability. The relations between Ti and volatile content and active energy are analyzed. Compared with the ignition temperatures measured in a bench scale fluidized bed and boiler test, Tis derived from TG-DTG method have nearly same tendency with changing volatile content, but have 100°C deviation below those measured in fluidized bed. The results strongly indicate that TG-DTG method can substitute the fluidized bed method and boiler test for measuring ignition temperature of a coal with an off-set adjustment.
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Sari, Yulia Erina, Alvin D. S. Ritonga, and Suwarno. "Comparative Study of Kraft Paper Aged in Natural Ester with XRD and TG/DTG Analysis." In 2019 International Conference on Electrical Engineering and Informatics (ICEEI). IEEE, 2019. http://dx.doi.org/10.1109/iceei47359.2019.8988785.
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Chen, J., S. Cheng, and S. Chou. "DSC, TG and infrared spectroscopic studies of HTPB and butacene propellant polymers." In 30th Joint Propulsion Conference and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1994. http://dx.doi.org/10.2514/6.1994-3176.
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Tang, Z. J., P. Fang, J. H. Huang, Z. X. Tang, and C. P. Cen. "Investigation on thermodynamics characteristics of biomass thermal decomposition using TG/DSC method." In 5th International Conference on Advanced Design and Manufacturing Engineering. Paris, France: Atlantis Press, 2015. http://dx.doi.org/10.2991/icadme-15.2015.177.
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Xue, Tian, Yong-he Han, Qi-zhi Zhao, and Ning Lyu. "Thermal Decomposition of CS by TG/DSC-FITR and PY-GC/MS." In 2015 International Conference on Mechatronics, Electronic, Industrial and Control Engineering. Paris, France: Atlantis Press, 2015. http://dx.doi.org/10.2991/meic-15.2015.208.
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Du, Lin, Wujing Wang, Weigen Chen, and Chao Wei. "Reaction mechanism of transformer oil pyrolysis based on TG-DSC and molecular simulation." In 2016 Conference on Diagnostics in Electrical Engineering (Diagnostika). IEEE, 2016. http://dx.doi.org/10.1109/diagnostika.2016.7736478.
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Singh, D. K., A. K. Govila, and V. K. Ganpate. "Characterisation of polyester resins and composites by differential scanning calorimetry (DSC) and thermogravimetry (TG)." In 1985 EIC 17th Electrical/Electronics Insulation Conference. IEEE, 1985. http://dx.doi.org/10.1109/eic.1985.7458603.
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Zhang, Hongliang, Yongbiao Yang, Jie Song, Ling Jiang, Jiancheng Yu, and Xudong Wang. "The study of the biomass pyrolysis kinetics and volatile product characteristics influencing on slagging basing on the TG-DTG-FTIR technology." In 2015 3rd International Conference on Machinery, Materials and Information Technology Applications. Paris, France: Atlantis Press, 2015. http://dx.doi.org/10.2991/icmmita-15.2015.208.
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