Development of advanced composite materials based on carbon fibers for the aerospace industry

En este trabajo se estudia el desarrollo de materiales compuestos de matriz polimérica reforzados con fibras de carbono para aplicaciones que presentan solicitaciones severas. Este es el caso de la industria aeroespacial, que utiliza componentes en cohetes y aeronaves que se ven sometidos a altas solicitaciones mecánicas y están expuestos a las altas temperaturas. Es por ello que se estudiaron materiales para diversas aplicaciones basados en fibras de carbono: preimpregnados de fibras y resina fenólica resistentes a altas temperaturas y laminados para procesar compuestos por técnicas de infusión. En el primer caso se efectuó el desarrollo completo de los materiales compuestos, partiendo de la síntesis de la resina, el procesamiento y caracterización de los preimpregnados, la fabricación de placas de material compuesto y su caracterización en términos de resistencia mecánica y al fuego. Se efectuaron ensayos en un calorímetro de cono, que permite determinar la velocidad de liberación de calor durante el proceso de combustión y analizar la emisión de volátiles a lo largo del proceso. En relación a los laminados para procesar compuestos por técnicas de infusión, se caracterizó un parámetro de vital importancia que determina la facilidad de la resina para impregnar el refuerzo durante el llenado de moldes: la permeabilidad del tejido de fibras de carbono. Este parámetro se caracterizó en diversas direcciones del tejido, a fin de obtener el denominado tensor de permeabilidad, que permite predecir los tiempos de infusión y patrones de flojo, minimizando el contenido de poros en el material final a través del control de la velocidad de avance de la resina en el molde.This work is focused on the development of carbon reinforced polymer matrix composite materials for high performance applications. Such applications are common in the aerospace industry, which uses components that are subjected to high mechanical stresses and work under high service temperatures. Taking into account this strategic industrial sector, materials for different applications were studied: high temperature carbon fabric/phenolic resin prepregs and carbon fabrics for infusion techniques. In the first case, composites materials were developed starting from the synthesis of the phenolic resin, the processing carbon/phenolic prepregs and the obtaining of composite plaques that were characterized in terms of mechanical properties and fire resistance. A cone calorimeter was used to study the fire behavior of the composites, obtaining the heat release rate evolution and the CO and smoke emission during the combustion process. In the second study, carbon fabrics were characterized in terms of a very important parameter that determines the impregnation mechanisms in infusion processes: the reinforcement permeability. This parameter was characterized for different directions of the fabric in order to obtain a tensor that allows predicting filling times and a flow patterns, minimizing void content in the final composites by controlling resin flow front velocity in the mold.Fil: Rodriguez, Exequiel Santos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); Argentina; Universidad Nacional de Mar del Plata. Facultad de Ingenieria; Argentina

Mechanical properties of geopolymer concretes reinforced with waste steel fibers

The article presents the research that try to determinate the possibilities of utilization the waste came from used tires to create the composites based on geopolymer matrix. The tire is multicomponent construction. It mainly consists of elastomer (rubber), metal and textile fibres such called textile cord. A lot of components causes difficulties in the tire recycling process. The main aim of the research was determinate the possibilities of recycling the waste steel from used tires in geopolymer composites and develop the eco-friendly material for construction industry. The matrix based on fly ash from power station located in city named Skawina (Poland) and fine sand at a ratio of 1:1. The process of activation was made by 10M sodium hydroxide solution combined with the sodium silicate solution. In order to manufacture these composites the addition of 2% and 3.5% of waste steel fibres by mass was applied. Also specimen without steel fiber reinforcement were made to get reference specimens. The waste steel fibres came from recycling company from Argentina - 'Regomax'. The specimens were prepared according to the methodology described in the standard EN 12390-1. The research methods used were: microstructure research, tensile strength and compressive strength tests as well as analysis of breakthroughs.Fil: Gailitis, R. Riga Technical University; LetoniaFil: Korniejenko, K. Cracow University Of Technology; PoloniaFil: Lach, M. Riga Technical University; LetoniaFil: Sliseris, J. Riga Technical University; LetoniaFil: Moran, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Rodriguez, Exequiel Santos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Mikula, J. Cracow University Of Technology; Poloni

Study of the ablative properties of phenolic/carbon composites modified with mesoporous silica particles

Mesoporous silica particles and carbon black were selected as fillers for a resol-type phenolic resin, to be used as a matrix for ablative materials. Composites were processed with the modified polymer and carbon fibers were used as continuous reinforcement. The ablative properties of the materials obtained were studied by the oxyacetylene torch test and the ablated samples were observed by scanning electron microscopy. Composites with 30 wt. % of carbon black achieved the lowest linear erosion rate and the highest insulation index, denoting the ability of the char produced to protect the virgin material. Considering that such composite has 44% by volume of carbon fibers, it could be inferred that its properties could be improved by increasing the fiber content and maintaining the amount of carbon black. The composite with 20 wt. % of mesoporous silica particles exhibited the lowest mass erosion rate, indicating a better stabilization of the char. Regarding dynamic-mechanical properties, the addition of particles induced a decrease in the modulus and glass transition temperature of all the systems studied.Fil: Asaro, Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Manfredi, Liliana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Rodriguez, Exequiel Santos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

MANDUKA: O HOMEM QUE NÃO SABIA MORRER. UM RELATO DO BAIXO UAUPES NA MEMÓRIA DOS POVOADORES INDIGENAS DA REGIÃO. / MANDUKA: THE MAN WHO DIDN´T KNOW HOW TO DIE. REPORT OF LOWER UAUPES IN THE MEMORY OF THE INDIGENOUSE SETTLERS OF THE REGION.

RESUMO A complexidade emblemática de Manduca, dispersa imageticamente por vários enclaves do Alto Rio Negro, deve-se fundamentalmente, e em primeira ordem, a sua condição de “filho da terra” enquanto cunhado dos Pira-tapuia, fato que o aproximava à categoria de nobre e lhe outorgava uma ampla prerrogativa que usou vilipendiosamente como forma de biopoder; dito em outras palavras, exercendo o controle dos corpos: controle tanatocrático;  desafiando qualquer tipo de restrição e limite sobre a vida de seus capangas e vassalos. Em segundo termo, sua vida de homem infame, de trajetória cruel e obscura, convertia-o num intocável, um pérfido ser, ávido de poder, figurando de forma exemplar e exemplificante, além da vida, enfim, um astuto conhecedor da região e dos medos da sua gente, que se acostumou vilmente a roubar vidas e ostentar uma autoridade que a cada instante referenciava nos gestos da morte. A seguinte proposta aborda a personagem de Manduca, comerciante do ciclo da borracha, através de um audiovisual produzido com os índios de fala tukano do Baixo Rio Uaupés, tendo como contexto cenográfico o próprio enclave do terror, a Ilha de Bela Vista. Este produto imagético-narrativo, que evoca desde o presente etnográfico uma sócio-espacialidade do terror na geografia do Uaupés, constitui também um dos elementos do processo de negociação em andamento pesquisa-intervenção social, entre comunidades do pensamento, em outras palavras, os tukano do rio Uaupés e os pesquisadores da Universidade Federal do Amazonas. Palavras-chaves: Espaços do terror Manduca. Baixo Uaupés. Tukano. Etnologia da intervenção. Amazônia Brasileira. ABSTRACT The emblematic complexity of Manduka, imagetically dispersed by several enclaves of the Upper Rio Negro, is mainly due to, and to first order, its status as "son of the land" as Pira-Tapuia brother-in-law, whose fact approached himself to the category of a noble and gave to him a wide prerogative, slightly used as a form of biopower; said in other words, exercising the control of the bodies: thanatocratic control; challenging any restrictions and limits over the life of his henchmen and vassals. In second term, his life of infamous man, cruel and obscure path, converted him into an untouchable and perfidious being, greedy for power, appearing in an exemplary manner, and exemplifying, beyond life. An astute expert of the region and the fears of his people, who got despicably used to steal lives and sporting an authority that every moment made references in the gestures of death. The following proposal addresses the character of Manduka, dealer of the rubber boom, through an audiovisual produced with the Indians of the Lower Rio Uaupes, who speak Tukano, having as scenographic context the enclave of terror itself, the Bela Vista island. This imagetic-narrative product that evokes from the ethnographic present a socio-spatiality of terror in the geography of Uaupes, also constitutes one of the elements of the negotiation process underway research-social intervention, among communities of thought, in other words, Tukano from Uaupes river and the researchers from the Federal University of Amazonas. Keywords: Spaces of terror. Manduka. Low Uaupes. Tukano. Ethnology of the intervention.Brazilian Amazon.

Study of saturated and unsaturated permeability in natural fiber fabrics

The main goal of this work is to understand how the main processing variables are affected when glass fibers are replaced by natural fibers in reinforced plastics. In this publication, a jute fabric was characterized in terms of its saturated and unsaturated permeability. It was found that fluid absorption and swelling are mechanisms present in natural fibers that reduce both permeabilities. Fluid absorption removes fluid from the main stream as it travels through the reinforcement, acting as a sink component and thus decreasing flow velocity during the unsaturated flow. Also, the saturation of the natural fibers cause swelling, reducing the porosity and increasing flow resistance during saturated flow.Fil: Francucci, Gaston Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Rodriguez, Exequiel Santos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Vázquez, Analía. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Key differences on the compaction response of natural and glass fiber preforms in liquid composite molding

In the present work, the effects of fiber structure and fluid absorption on the compaction behavior of jute woven fabrics and sisal mats were analyzed and compared with the response of glass fiber mats. It was found that the fiber content that can be achieved with a certain compaction pressure is lower in the case of natural fiber preforms. In addition, due to the hollow structure of these natural fibers, jute and sisal preforms suffered larger permanent deformation than glass fiber preforms after the compressive loading cycle. In addition, it was found that fluid absorption reduced the compaction pressure in natural reinforcements due to fiber softening. These phenomena were not observed in glass fiber mats.Fil: Francucci, Gaston Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación En Ciencia y Tecnología de Materiales (i); ArgentinaFil: Vazquez, Analia. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Tecnologia En Polimeros y Nanotecnologia; ArgentinaFil: Rodriguez, Exequiel Santos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación En Ciencia y Tecnología de Materiales (i); Argentin

Thermal degradation and decomposition of jute/vinylester composites

Thermal analysis of jute fibre reinforced vinylester resin with 30 vol% of fibre were performed by TG/DTG under dynamic conditions. The fibres were treated with alkaline solution at different temperatures and the final composition (cellulose, hemicellulose and lignin) of the fibre was determined by chemical analysis. Apparent activation energies were determined using a variety of conventional thermogravimetric methods. Two peaks were found in the composite differential curves: the first peak close to 327 and the second peak at 408°C. The apparent activation energy values for the second peak decreased when fibre were treated. The addition of the jute fibres produced a slightly decrease in the thermal stability of the composites. © 2006 Akadémiai Kiadó, Budapest.Fil: Alvarez, Vera Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Rodriguez, Exequiel Santos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Vázquez, Analía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

Failure analysis of a GFRP pipe for oil transport

The study was conducted on a pipe sample of GFRP. There was widespread damage in the internal structure of the tube. The flow area was blocked due to landslides helical fibers. The matrix was an epoxy–anhydride system (Diglycidyl Ether of Bisphenol A). There was an advanced state of diffusive processes that reduced the glass transition temperature (Tg) of the material to critical levels. The material showed a major irreversible hydrolytic attack. The mechanical behavior would indicate a considerable degree of structural compromise. The sample showed an advanced state of degradation, with clear signals of processes activated at temperatures close to Tg and catalyzed by the diffusion of low molecular weight organic species. The irreversible chemical degradation process especially attacked the fiber–matrix interface reducing the mechanical performance.Fil: Rodriguez, Exequiel Santos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); Argentina; Universidad Nacional de Mar del Plata. Facultad de Ingenieria; Argentina;Fil: Alvarez, Vera Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); Argentina; Universidad Nacional de Mar del Plata. Facultad de Ingenieria; Argentina;Fil: Montemartini, Pablo Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); Argentina; Universidad Nacional de Mar del Plata. Facultad de Ingenieria; Argentina

Effect of Halloysite Nanotubes on Matrix Microcracking in Carbon Fiber/Epoxy Composites

Matrix microcracking is considered the main factor responsible for the gas permeation in linerless pressure vessels and storage tanks. The addition of halloysite nanotubes (HNTs) to them at different concentrations was studied in order to enhance their microcrack resistance. A 50% increase in the cracking onset stress was found at a 5% addition of HNTs to the epoxy matrix. Moreover, a 60% increase was observed at a similar level of microcrack density compared with that of neat epoxy. A reactive diluent was used as an alternative to keep the viscosity suitable for the filament winding process and to offset the rise in viscosity by HNT incorporation. Despite the fact that the matrix fracture toughness increased even to 10% of HNTs, no growth in the microcrack resistance was found at more than 5% of HNTs. As a result, it was concluded that the microcracking phenomenon can be affected not only by the matrix fracture toughness, but also by the residual thermal stresses.Fil: Churruca, María José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Moran, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Rodriguez, Exequiel Santos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin