Two novel methods for the sulphur vulcanisation of NR, BR and EPDM rubbers using N-tert-butyl-2-benzothiazole sulphenamide (TBBS) accelerator and zinc oxide (ZnO) activator have been developed. In one method, the optimum loading of TBBS and ZnO were measured for some sulphur-filled NR, BR and EPDM rubbers. The cure systems for the NR were (S/TBBS/ZnO), (1/1.5/0.2), (2/1.5/0.3), (3/1.5/0.25), and (4/3.5/0.2), for the BR, (0.5/1.75/0.2) and (1/3/0.2), and for the EPDM, (1/1/0.075). The cure was very efficient in spite of reducing the amount of TBBS and ZnO chemicals. In another method which used a single additive component in the form of a powder (TBBS/ZnO: 350mg/1g), the loading of the powder in NR was raised increasingly from 0.63 to 5.63 phr, the scorch time was unchanged and the optimum cure time reduced at 1.25 phr powder. The rate of cure accelerated at 1.25 phr powder. The crosslink density reached its maximum value at 5.63 phr powder. This method reduced the TBBS and ZnO requirement in the cure system by 85wt%. Solid kaolin filler pre-treated with a sulphur-bearing mercaptosilane was used to reinforce NR, BR and EPDM rubbers. For NR, to react the sulphur in the silane on the kaolin surface with the rubber chains and optimise the reaction between the two, 16 phr TBBS and 0.2 phr ZnO were added to the kaolin-filled rubber. The hardness and Young s modulus increased and compression set decreased when up to 3 phr elemental sulphur was included in the kaolin-filled rubber with 16 phr TBBS and 0.2 phr ZnO. The tensile strength, elongation at break, stored energy density at break, and tear energy of the rubber vulcanisate reduced when elemental sulphur was added. Notably, the inclusion of elemental sulphur was the key factor in controlling the rubber properties. In an extended work, 60 phr silane pre-treated kaolin was mixed with NR, BR and EPDM and the rubbers were cured using the novel cure systems developed earlier. The effect of 140 phr kaolin on the properties of NR was also investigated. For NR, the hardness increased by 64% when 60 phr kaolin was added and the trend continued rising by another 28% when the loading of kaolin reached 140 phr. Similarly, the Young s modulus rose by 170% with 60 phr kaolin and then by an extra 148% when the full amount of kaolin, i.e. 140 phr, was reached. The tensile strength and tear energy were unchanged and the elongation at break and stored energy density at break deteriorated by a total of 65% and 34%, respectively with 140 phr kaolin. The compression set of the unfilled rubber was 41%, and it then rose to 64% and 71%, when 60 and 140 phr kaolin was added, respectively. For BR, the hardness increased by 23% and for EPDM, by 34%, respectively when 60 phr kaolin was incorporated in the rubbers. For BR, the tensile strength, elongation at break and Young s modulus rose by 759%, 256% and 114%, respectively. The compression set of the unfilled BR was 9.4%, and subsequently rose to 26% when 60 phr kaolin was mixed with the rubber. For EPDM, the tensile strength, elongation at break and Young s modulus improved by 964%, 332% and 71%, respectively. For BR, the stored energy density at break and tear energy were increased by 2442% and 536%, respectively and for EPDM, by 3133% and 1479%, respectively. The compression set of the unfilled EPDM was 39%, and afterward increased to 48% with 60 phr kaolin. Kaolin was found to be extending or non-reinforcing filler for the strain-induced crystallising NR and highly reinforcing for the non-crystallising BR and EPDM.

Made available in DSpace on 2014-06-11T19:26:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-12-07Bitstream added on 2014-06-13T18:29:43Z : No. of bitstreams: 1 kumayama_dm_me_rcla.pdf: 1380181 bytes, checksum: 01a9c44a3ed685a8b32c697e52baed4c (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O crescente mercado brasileiro na área de revestimentos cerâmicos e a necessidade de conhecer melhor as propriedades dos esmaltes e engobes motivaram este estudo, com o objetivo de fazer uma análise comparativa da matéria-prima caulim para engobes e esmaltes. Com intuito de caracterizar os caulins de diferentes procedências geológicas e observar diferenças de comportamento nas suspensões de engobes e esmaltes foram feitos ensaios de viscosidade, cor de queima, microscopia eletrônica de varredura, microscopia óptica e colorimetria. Este estudo também possibilita formular melhor engobes e esmaltes tendo em vista suas características físico - químicas. Os caulins apresentam diferenças quanto à granulometria, viscosidade e mineralogia. A partir deste estudo constatou-se que a procedência geológica do caulim influi em suas propriedades, sendo os pegmatíticos, já bem aceitos no mercado, os que têm melhores propriedades, incluindo alvura. / The Brazilian increase business on ceramic tile and the need of better knowing at the proprieties of ceramic enamels and engobes provided this study, with the objetive of doing comparative analyzes of kaolin for engobes and enamels. At this paper were done assays of reology( viscosity), burned color, sweepings electronic microscopy, optical microcopy and colorimetric assays, to the characterization of different geological origin of the kaolins. This study helps the best formulation of engobes and enamels with the characteristics physicist-chemical. Observing this paper that the different geological origin modify its proprieties, the pegmatite ones have the best proprieties and they have already accepted in the market. This study show differences in kaolin since viscosity to mineralogy.

Orientador: Antenor Zanardo / Banca: Maria Margarita Torres Moreno / Banca: José Francisco Marciano Motta / Resumo: O crescente mercado brasileiro na área de revestimentos cerâmicos e a necessidade de conhecer melhor as propriedades dos esmaltes e engobes motivaram este estudo, com o objetivo de fazer uma análise comparativa da matéria-prima caulim para engobes e esmaltes. Com intuito de caracterizar os caulins de diferentes procedências geológicas e observar diferenças de comportamento nas suspensões de engobes e esmaltes foram feitos ensaios de viscosidade, cor de queima, microscopia eletrônica de varredura, microscopia óptica e colorimetria. Este estudo também possibilita formular melhor engobes e esmaltes tendo em vista suas características físico - químicas. Os caulins apresentam diferenças quanto à granulometria, viscosidade e mineralogia. A partir deste estudo constatou-se que a procedência geológica do caulim influi em suas propriedades, sendo os pegmatíticos, já bem aceitos no mercado, os que têm melhores propriedades, incluindo alvura. / Abstract: The Brazilian increase business on ceramic tile and the need of better knowing at the proprieties of ceramic enamels and engobes provided this study, with the objetive of doing comparative analyzes of kaolin for engobes and enamels. At this paper were done assays of reology( viscosity), burned color, sweepings electronic microscopy, optical microcopy and colorimetric assays, to the characterization of different geological origin of the kaolins. This study helps the best formulation of engobes and enamels with the characteristics physicist-chemical. Observing this paper that the different geological origin modify its proprieties, the pegmatite ones have the best proprieties and they have already accepted in the market. This study show differences in kaolin since viscosity to mineralogy. / Mestre

A study was made of the problem of differential thermal analysis utilizing statistical experimental design. A factorial type of design was chosen to yield maximum efficiency of the data obtained. “Lakeland”, Florida Kaolin of commercial whiteware grade was selected because of its relative purity. Due to the large number of samples to be analyzed, it was found necessary to choose a commercial brand rather than a very pure kaolinite which was found impossible to obtain in sufficient quantity. A statistical 2x3x3 factorial design was used and the calculations incident thereto made in detail. Data, which to the eye appeared erratic, was found to be acceptable within the probability limits of error of the experiment. The effects of two different furnaces, three rates of heating, and three densities of the samples were analyzed to determine the area under the endothermic reaction peaks as measured by Cr-Al differential thermocouples. It was found that densities and rates both yielded highly significant values and that the interactions of the two showed significant results when examined by a distribution of “F”¹. These effects were analyzed for the regressions therein and were found to be significant in the linear trends only. From this indication it would seem evident that the optimum density and rate of heating had not been reached in the limits of this experiment. Replications and furnaces did not yield significant results when tested by “F” distribution. From this it was deduced that the experiment could be conducted with sufficient precision under the present procedure and conditions and reproducibility obtained irrespective of the furnace used. Examination of the data will indicate that the level of the two furnaces is different, but the trends within are in the same areas. A certain amount of erratic data were obtained due to a lag in heating rates and this difficulty will be discussed. / Master of Science

La kaolinite est une des matières les plus utilisées depuis la plus haute antiquité. En effet, du fait de leurs propriétés, les argiles sont utilisées comme charges dans beaucoup d'applications industrielles notamment dans le domaine de la papeterie, de la céramique, de l'industrie cimentaire, dans le verre etc. Leur utilisation est liée à leurs bonnes propriétés optiques, minéralogiques et chimiques. L'ajout de kaolinites submicroniques pose cependant de multiples difficultés liées en particulier à leur incompatibilité avec la plupart des polymères et à la difficulté de les exfolier. Dans ce contexte, il est proposé, dans ce travail, une nouvelle voie de valorisation de la kaolinite à la fois comme charge renforçante et/ou compatibilisante et comme retardateur de flamme dans des matrices thermoplastiques.La surface de la kaolinite est tout d'abord traitée avec différents agents de type silane. Ces charges traitées ont été incorporées (entre 4 et 12% en volume dans le polypropylène et le polyamide et jusqu'à 35 % en volume dans le EVA) ce qui a permis à la fois de modifier les propriétés élastiques, les contraintes seuil ainsi que les performances au choc par rapport aux matrices contenant les charges non traitées et d'établir un lien entre ces différentes performances et la dispersion de la charge (estimée par analyse d'images).Due à l'hétérogénéité de la surface de la kaolinite, une nouvelle méthode pour modifier sa surface est proposée. Cette méthode est basée sur la modification sélective des alumines de surface avec des acides phosphoniques. Les silices de surface étant libres pour réagir avec un autre agent de modification, soit un silane porteur d'une fonction époxy, soit une amine. Il a été mis en évidence, dans un mélange PP/PA, que la kaolinite modifiée avec l'acide phosphonique à une tendance à se placer à l'interface des polymères et pourrait alors jouer un rôle de comptabilisation.Finalement, des études sur le comportement au feu des différentes formulations ont permis de montrer que la kaolinite a un grand potentiel en tant que retardateur de flamme. La réduction du pic de débit calorifique (pHRR) semble être en lien étroit avec le comportement rhéologique des polymères chargés et donc très sensible au traitement de surface. / Kaolinite is one of the most used mineral fillers since ancient times. Indeed, because of their properties, this clay is used as filler in many industrial applications, particularly in the industry of paper, cement, ceramics, glass etc... This use is related to their good optical, mineralogical and chemical properties. However the addition of kaolinite in polymer matrices leads to some difficulties especially related to their incompatibility with most polymers. In this context, this work proposes a new path of development of kaolinite as functional filler for the mechanical reinforcement and/or compatibilization of thermoplastic matrices, as well as a flame retardant.The surface of kaolinite was first modified with different silane agents. These fillers were then incorpored between 4 and 12% by volume in polypropylene and polyamide and 35% by volume in EVA copolymer. The surface treatment of kaolinite allowed the modification of the elastic and impact performances of composites compared to untreated fillers. These changes were related to the filler dispersion in the polymer matrix (dispersion was estimated by image analysis). Due to the surface heterogeneity of kaolinite (silica and alumina faces), a new method for a regiolelective surface modification was developed. This method was based on a first step of selective modification of the alumina faces with a product bearing a phosphonic acid group. In a second step, the silica facesare treated with a silane compound. It has been highlighted in a PP/PA blend that the regioselective surface modified kaolinite tend to be placed at the interface between the two polymer matrices.Finally, the study of the fire behavior of different formulations showed a great potential as flame retardant for kaolinite. Reduction of peak heat release rate (pHRR) values seems to be closely related to the rheological behavior of filled polymers and therefore very sensitive to surface treatment.

L'utilisation du kaolin calciné, sous forme de métakaolin, comme matériau pouzzolanique pour le mortier et le béton a suscité une attention considérable ces dernières années. Le travail actuel décrit les résultats d'un projet de recherche lancé pour étudier la calcination d'un kaolin local sous diverses températures (650-950°C) et durées (2, 3 et 4 heures) qui ont produit le métakaolin avec une activité pouzzolanique élevée. L'activité pouzzolanique a été évaluée par des méthodes de la chaleur d'hydratation et la résistance à la compression à 28 jours. L'activité maximale a été obtenue à une température de 850°C pendant 3 heures. Les résultats observés établissent qu'une augmentation de la chaleur d'hydratation et de la résistance à la compression a été obtenue lorsque le ciment Portland Ordinaire a été remplacé par 10% de métakaolin. L'utilisation du ciment ternaire améliore la résistance au jeune âge et à long terme. La durabilité a été également améliorée où une meilleure résistance des mortiers à l'attaque des acides a été observée. / The utilisation of calcined clay, in the form of metakaolin as a pozzolanic material for mortar and concrete has received considerable attention in recent years. The present work describes the results of a research project initiated to study the calcination of a local kaolin at various temperatures (650-950°C) and durations (2, 3 and 4 hours) to produced a metakaolin with a high pozzolanic activity. The pozzolanic activity was assessed by 28-days compressive strength and hydration heat methods. The maximum identified activity was obtained at 850°C for 3 hours duration. The observed results establish that an increase of both hydration heat and compressive strength was obtained when ordinary Portland cement was replaced by 10% metakaolin. The use of ternary blended cement improves the early age and the long-term compressive strength. The durability was also enhanced as better acidic resistance was observed.

Das Kemmlitzer Kaolinrevier liegt ca. 60 km nordwestlich der sächsischen Hauptstadt Dresden zwischen den Flüssen Elbe und Mulde. Die bisher bergbaulich genutzten Lagerstätten sind durch tiefgründige Verwitterung im Zeitraum Oberkreide bis Miozän aus verschiedenen permischen Vulkaniten, vorwiegend quarzreichen Porphyren, hervorgegangen. Die Kaoline enthalten neben verwitterungsresistentem Quarz an Tonmineralen vor allem Kaolinit und in wechselnden Anteilen Illit-Montmorillonit-Mixed-Layer-Minerale. Die Mächtigkeit der Verwitterungskruste beträgt 10 bis 40 m, gelegentlich auch mehr. Haupteinflüsse auf den Erhaltungsgrad haben eine junge Bruchtektonik und pleistozäne Erosionsvorgänge. Die Deckschichten der Kaoline werden überwiegend von verschiedenen pleistozänen und untergeordnet tertiären Sedimenten gebildet. Die Kaoline um Kemmlitz wurden Anfang des 19. Jahrhunderts entdeckt und seit 1883 intensiv bergbaulich genutzt. Der Abbau der Lagerstätten erfolgte zunächst im Tiefbau, verstärkt ab 1953 und gegenwärtig ausschließlich im Tagebaubetrieb. Durch nassmechanische Aufbereitung der Rohkaoline wird in mehreren Klassierstufen der Quarz weitestgehend abgetrennt und der Wertstoff Tonmineral angereichert. Die Schlämmkaoline finden aufgrund äußerst geringer Schadstoffgehalte (Fe, Ti) und günstiger Verarbeitungseigenschaften vor allem bei der Herstellung von Geschirr- und Elektroporzellan, Sanitärkeramik und Fliesen Verwendung. Im Kemmlitzer Revier wurden bis Ende 2004 ca. 31 Mio. t Kaolin abgebaut, die Vorratsbasis der nächsten 50 Jahre ist gesichert und weitere Ressourcen sind bekannt.

Submitted by Viviane Lima da Cunha (viviane@biblioteca.ufpb.br) on 2016-07-28T13:17:58Z No. of bitstreams: 1 arquivototal.pdf: 2098256 bytes, checksum: ecc2e6022cdb0ed0a21b9127d6c65e3c (MD5) / Made available in DSpace on 2016-07-28T13:17:58Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2098256 bytes, checksum: ecc2e6022cdb0ed0a21b9127d6c65e3c (MD5) Previous issue date: 2016-04-22 / Refractory ceramics are ceramic materials which have among its main features the ability to withstand high temperatures without melting or decomposed and to remain non-reactive and inert when exposed to harsh environments. These characteristics define the purposes for which these materials are proposed, which can be highlighted applications linings, heat treatment and refining of metals, manufacture of glass and power generation. With the constant evolution of the refractory industry, increasingly necessary it becomes the search for technological means to bring improvements to the cost / benefit ratio of the materials produced. The use of natural raw materials is a point of extreme importance in the refractory industry, since these raw materials are found in deposits scattered in the earth's crust. The mullite (3Al2O3.2SiO2) is an alumino-silicate that due to its special properties has been described as one of the most important refractory ceramic of today. The kaolin waste obtained in the second step of the primary kaolin processing can be used as a source for synthesizing mullite. In this context, this study aimed to use the mixture design (kaolin, kaolin waste and alumina) to obtain mullite based refractory ceramics. The samples were pressed and sintered between 1300 and 1550 °C and then subjected to the determination of physical and mechanical properties, characterization of crystalline phases by XRD and microstructural analysis by SEM. The results indicated obtaining mullite from 1300 °C. It was observed that the mullitization process was affected by the concentration of the raw materials and the sintering temperature. In compositions rich in kaolin waste the sintering mechanism by liquid phase favors the densification process. A specific formulation, containing 50 wt.% of kaolin and 50 wt.% of kaolin waste (mica-rich) had twice the mechanical strength of pure kaolin after sintering at 1300 °C. This study demonstrated the possibility of obtaining mullite with up to 94% of relative density through reactive sintering of kaolin/residue kaolin/alumina mixtures at temperatures as low as 1300 °C. / Cerâmicas refratárias são materiais cerâmicos que possuem entre suas principais características a capacidade de resistir a temperaturas elevadas sem fundir-se ou decompor-se e de permanecerem não reativos e inertes quando expostos a ambientes severos. Tais características definem os fins aos quais estes materiais se propõem, podendo-se destacar aplicações em revestimentos de fornos, tratamentos térmicos e refino de metais, fabricação de vidros e na geração de energia. Com a constante evolução da indústria refratária, torna-se cada vez mais necessária a busca de meios tecnológicos que tragam melhorias à relação custo/benefício dos materiais produzidos. O uso de matérias-primas naturais é um ponto de extrema importância na indústria de refratários, já que essas matérias-primas são encontradas em depósitos espalhados na crosta terrestre. A mulita (3Al2O3.2SiO2) é um alumino-silicato que em virtude de suas propriedades especiais tem se qualificado como uma das mais importantes cerâmicas refratárias da atualidade. O resíduo de caulim, obtido na segunda etapa do beneficiamento de caulins primários, pode ser utilizado na síntese de mulita. Neste contexto, este trabalho teve como objetivo utilizar o delineamento de misturas (caulim, resíduo de caulim e alumina) para a obtenção de cerâmicas refratárias à base de mulita. Corpos de prova obtidos por prensagem uniaxial foram sinterizados entre 1300 e 1550 °C e, em seguida, submetidos à determinação das propriedades físico-mecânicas, caracterização de fases cristalinas por DRX e análise microestrutural por MEV. Os resultados indicaram a obtenção de mulita a partir de 1300 °C. Observou-se que o processo de mulitização foi afetado pela concentração das matérias-primas e pela temperatura de sinterização. Nas formulações ricas em resíduo de caulim o mecanismo de sinterização por fase líquida favoreceu o processo de densificação. Uma formulação específica, contendo 50 % de caulim e 50 % de resíduo de caulim (rico em mica), apresentou o dobro da resistência mecânica do caulim puro após sinterização a 1300 °C. Este estudo demonstrou a possibilidade de obter mulita com até 94% de densidade relativa via sinterização reativa de misturas caulim/resíduo de caulim/alumina a temperaturas tão baixas quanto 1300 °C.

Doctoral thesis is focused on the study, research and development of heat insulating moulded refractory materials. The replacement of shaped instead of unshaped refractories is recently and strongly industrially demanded and belongs to ongoing research topics. With the increasing demand of energy savings, the excellent insulation properties are essential. The insulating properties of castables are the result of targeted porosity formation. The porosity is coming from the controlled air intrusion into material resulted to foamed structure. The foaming process was achieved by mixing of separately prepared aqueous foam into raw castable slurry or by in situ foaming of intensively mixed castable slurry with the surfactant additive. Nevertheless, the study of foam behaviour and the influence of additives on binder hydration and setting processes (i.e. calciumaluminate cement) was substantial for successful preparation of the experimental samples. The two types of the experimental samples were prepared. The first one was based on mixing of kaolin slurry with pre-prepared aqueous foam, whereas the de-aglomeration ability of kaolin specie was utilized to water-particle film formation. In situ foaming of multicomponent system is the second one. The both processes brought some negative attributes, so the optimal properties of prepared castables were achieved by their combination.

Das Kemmlitzer Kaolinrevier liegt ca. 60 km nordwestlich der sächsischen Hauptstadt Dresden zwischen den Flüssen Elbe und Mulde. Die bisher bergbaulich genutzten Lagerstätten sind durch tiefgründige Verwitterung im Zeitraum Oberkreide bis Miozän aus verschiedenen permischen Vulkaniten, vorwiegend quarzreichen Porphyren, hervorgegangen. Die Kaoline enthalten neben verwitterungsresistentem Quarz an Tonmineralen vor allem Kaolinit und in wechselnden Anteilen Illit-Montmorillonit-Mixed-Layer-Minerale. Die Mächtigkeit der Verwitterungskruste beträgt 10 bis 40 m, gelegentlich auch mehr. Haupteinflüsse auf den Erhaltungsgrad haben eine junge Bruchtektonik und pleistozäne Erosionsvorgänge. Die Deckschichten der Kaoline werden überwiegend von verschiedenen pleistozänen und untergeordnet tertiären Sedimenten gebildet. Die Kaoline um Kemmlitz wurden Anfang des 19. Jahrhunderts entdeckt und seit 1883 intensiv bergbaulich genutzt. Der Abbau der Lagerstätten erfolgte zunächst im Tiefbau, verstärkt ab 1953 und gegenwärtig ausschließlich im Tagebaubetrieb. Durch nassmechanische Aufbereitung der Rohkaoline wird in mehreren Klassierstufen der Quarz weitestgehend abgetrennt und der Wertstoff Tonmineral angereichert. Die Schlämmkaoline finden aufgrund äußerst geringer Schadstoffgehalte (Fe, Ti) und günstiger Verarbeitungseigenschaften vor allem bei der Herstellung von Geschirr- und Elektroporzellan, Sanitärkeramik und Fliesen Verwendung. Im Kemmlitzer Revier wurden bis Ende 2004 ca. 31 Mio. t Kaolin abgebaut, die Vorratsbasis der nächsten 50 Jahre ist gesichert und weitere Ressourcen sind bekannt.