Artigos científicos, teses e dissertações
Publicados nas melhores instituições de ensino

A comparative study of bulk-fill composites: degree of conversion, post-gel shrinkage and cytotoxicity

Abstract: Bulk-fill composites are claimed to be restorative materials used in deep preparations and effectively photoactivated in layers up to 4 mm. The aim of the present study was to evaluate the degree of conversion, post-gel volumetric shrinkage, and cytotoxicity of six bulk...

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Estudo da obtenção e caracterização de compositos reforçados com fibras de carbono para aplicação como material isolante termico de sistemas aeroespaciais

Thermal and mechanical performance of carbon fiber reinforced composites (CRFC) have been contributed to the use of these materials in aerospace systems. However, due to the susceptibility to the oxidation in temperatures higher than 773 K, the materials processes and evaluations...

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Evaluation of carbon fiber composites modified by in situ incorporation of carbon nanofibers

Nano-carbon materials, such as carbon nanotubes and carbon nanofibers, are being thought to be used as multifunctional reinforcement in composites. The growing of carbon nanofiber at the carbon fiber/epoxy interface results in composites having better electrical properties than c...

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Analysis of the fracture behavior of polypropylene: sawdust composites

Natural fiber reinforced composite is an emerging area in Polymer science. The use of lignocellulosic materials in thermoplastic composites may contribute to reduce the waste of vegetal biomass. The natural fibers are biodegradable, low cost materials having density and specific ...

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Preparation and characterization of biodegradable composites based on Brazilian cassava starch, corn starch and green coconut fibers

Increasing search for new materials with high premium on eco-friendliness, new trend is emerging in materials development such as composites, which are well established for a wide variety of applications. With growing interest and importance of renewable bioresources has led to m...

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Effect of the fiber reinforcement on the low energy impact behavior of fabric reinforced resin matrix composite materials

The influence of the fiber used as reinforcement in resin matrix composite materials submitted to repeated low energy impacts is analyzed. The aramid, glass and carbon fiber composites were submitted to drop weight tests from 0.5m and from 1m. The number of impact events necessar...

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Effect of the chemical attack on the properties of cimentititous composites with partial substitution of ash from sugar cane bagasse in natura

ABSTRACT Seeking the reutilization of waste from agriculture and urban sources, studies have presented an option in the inclusion of such waste into new low-cost materials that are environmentally viable. One possibility is the reutilization of sugarcane bagasse ashes (SBA), the ...

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Investigations on cementitious composites based on rubber particle waste additions

The amount of waste rubber has gradually increased over recent years because of over-growing use of rubber products. The disposal of waste rubber has caused serious environmental problems. The incorporation of recycled materials into cementitious composites is a feasible alternat...

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Biocomposites of lignin-, tannin- and glyoxal- based polymeric matrices reinforced with natural fibers / Biocompósitos a partir de matrizes poliméricas baseadas em lignina, tanino e glioxal reforçadas com fibras naturais

The present study aimed at developing biocomposites combining polymeric matrices and reinforcement agents, employing the highest possible proportion of materials obtained from natural sources. Phenolic resins are widely known and used due to their excellent properties, such as di...

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Nanostructured composites based on carbon nanotubes and epoxy resin for use as radar absorbing materials

Nanostructured polymer composites have opened up new perspectives for multifunctional materials. In particular, carbon nanotubes (CNTs) present potential applications in order to improve mechanical and electrical performance in composites with aerospace application. The combinati...

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Estudo comparativo entre materiais metálicos e compósitos poliméricos para aplicações mecânicas na indústria automobilistica

Aluminum and plastic composites used in the automotive industry is a reality and increases in new projects. Materials and components are responsible for the most part of vehicle costs and the materials mix is changing continually due to light-weight solutions to reduce vehicle co...

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Studies on the properties of rice-husk-filled-PP composites: effect of maleated PP

Rice husk is a by-product of rice milling process that usually finds inadequate final disposal (burning, land filling). Thermoplastics composites filled with rice husk flour are materials that offer an alternative for using this agricultural resource viewing the production of low...

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Influence of coupling agents on the adhesion force of dissimilar overmolded polymers: a digital image correlation analysis

ABSTRACT The increase in the technical and functional requirements of plastic items has led the development of multimaterials. To achieve a good performance in the adhesion of dissimilar materials, in this case, polypropylene and coconut fiber composites, it is fundamental to und...

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Conductive Composites Based on Polyurethane and Nanostructured Conductive Filler of Montmorillonite/Polypyrrole for Electromagnetic Shielding Applications

In this study, composites based on polyurethane (PU) derived from castor oil and montmorillonite/polypyrrole doped with dodecylbenzenesulfonic acid (MMt-PPy.DBSA) were developed. In order to investigate the potential use of these materials for electromagnetic shielding applicatio...

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A review on the development and properties of continuous fiber/epoxy/aluminum hybrid composites for aircraft structures

Weight reduction and improved damage tolerance characteristics were the prime drivers to develop new family of materials for the aerospace/aeronautical industry. Aiming this objective, a new lightweight Fiber/Metal Laminate (FML) has been developed. The combination of metal and p...

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Development of graphite-polymer composites as electrode materials

Graphite powder was mixed to polyurethane, silicon rubber and Araldite® (epoxy) in order to prepare composite materials to be used in the preparation of electrodes. Results showed that voltammetric response could be obtained when at least 50% of graphite (w.w-1) is present in the...

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Investigação das características tribológicas e ambientais de termoplásticos de engenharia especiais para uso em materiais de atrito. / Investigation of tribological and environmental characteristics of high performance thermoplastics to friction materials.

Organic clutch friction facings are basicly composed of an organic matrix, fillers, solid lubricants and reinforcing fibers. An organic matrix has a structural function and has a large influence over the tribological properties of the system (coefficient of friction and wear rate...

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Toxicity Testing of Restorative Dental Materials Using Brine Shrimp Larvae (Artemia salina)

This study investigated the effect of extracts of different composites, glass ionomer cement (GIC)s and compomers on the viability of brine shrimp larvae. Ethanolic extracts of four dental composites (Z-100; Solitaire 2; Filtek P60 and Synergy), a conventional GIC (Ketac-Fil), a ...

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Vegetal fibers in polymeric composites: a review

The need to develop and commercialize materials containing vegetal fibers has grown in order to reduce environmental impact and reach sustainability. Large amounts of lignocellulosic materials are generated around the world from several human activities. The lignocellulosic mater...

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Influência de cargas de talco nas propriedades microestruturais e mecânicas na matriz de carbetos de silício em compósitos de matriz cerâmica

Ceramic Matrix Composites (CMC) are the most recent materials in field composites. The main factors for the good acting of these materials are the choice: of the matrix material, of the reinforcement, of the processing and chemical composition. Ceramic materials possess elastic m...

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