RESUMO A produção de compósitos à base de produtos derivados de resíduos industriais conduziu o presente estudo, agregando valor aos resíduos de indústrias metalúrgicas e siderúrgicas, o que é revertido em bem à sociedade. Os materiais geopoliméricos podem ser uma das soluções para a destinação dos resíduos industriais gerados por esses setores. O objetivo do estudo foi investigar a relação entre sólido/líquido para produção de corpos-de-prova obtidos pela reação de geopolimerização, utilizando escória de aciaria de convertedor e de panela, ou seja, processo de Linz Donawitz (LD) e de ladle furnace (LF), respectivamente. As amostras dos resíduos foram sintetizadas a partir de uma solução alcalina de hidróxido de potássio 8 M (KOH), nas proporções de 1.2; 1.4 e 1.6 g/v (sólido/líquido). As análises de composição química, estabilidade térmica, microestrutura, quantificação de fases cristalinas e porosidade foram realizadas por espectroscopia de fluorescência de raios X (FRX), espectroscopia de infravermelho por transformada de Fourier (FTIR), análise termogravimétrica (TGA), microscopia eletrônica de varredura com fonte de emissão de campo (MEV-FEG), difratometria de raios X (DRX) e determinação de densidade pelo princípio de Arquimedes. Os resultados indicaram que os geopolímeros obtidos a partir das escórias de aciaria geraram peças com estabilidade dimensional e altas possibilidades de aplicações como materiais de engenharia. Observou-se que a razão solido/líquido foi um ponto importante na síntese dos compósitos, uma vez que as amostras com razão 1.6 apresentaram um aspecto com maior coesão entre as partículas e maiores valores de densificação em relação às amostras com razões 1.2 e 1.4.

ABSTRACT Production of composites based on derivative products of industrial wastes was presented in this study, which aggregate value to metallurgical, steelmaker wastes of the industries, and this is reversed in beneficial effects to society. Geopolymeric materials can be a solution to industrial residues generated for these sectors. The objective of study was the investigation between a solid/liquid relationship to production of specimens obtained from geopolymerization reaction, using steelmaking slags by process of Linz Donawitz (LD) and ladle furnace (LF), respectively. Samples of the residues were synthesized from an alkaline solution of 8M potassium hydroxide (KOH) in the 1.2, 1.4 and 1.6 g/v proportions (solid/liquid). Analyses of chemical composition, thermal stability, microstructure, amount of crystallinity phases and porosity were evaluated to XRF, FTIR, TGA, SEM-FEG and Archimedes’ principle obtained by reaction geopolymerization through the steelmaking slags (LF and LD), respectively. The results indicated that obtained geopolymers from steelmaking slags developed specimens with dimensional stability and high possibilities of applications, as engineering materials. The results indicate that the solid / liquid ratio is an important point in the geopolymerization process, since the 1.6 samples presented a more cohesive appearance and higher densification values than the 1.2 and 1.4 samples.

This work aimed to produce and evaluate the ballistic behavior of niobo-phosphate glass-doped alumina composites. The niobo-phosphate glass (30% Nb2O5- 30% P2O5- 20% CaO - 20% CaF2, by mol) were added to the alumina in six different weight percentages. The composite with the highest densification, measured by the Archimedes assay, was used for the ballistic tests. X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray spectroscopy by dispersive energy (EDX) were also performed. The sintered samples were enveloped on two 1020 steel plates for the residual velocity test. The best results of densification were obtained for the niobo-phosphate glass addition of 4 wt%, which was not detected the AlPO4 phase formation. From the residual velocity test, it was observed a better energy absorption for the doped alumina, in relation to pure alumina. Therefore, it is indicated that the niobo-phosphate glass addition of 4 wt% worked properly as sintering aid for alumina, enhancing its properties and performance.

In this study, polymeric nanocomposites based on poly(methyl methacrylate) (PMMA) and silicon carbide (SiC) nanoparticles were prepared by radical mass polymerization in the presence of filler. Nanoparticles of SiC with and without surface treatment with organosilane were obtained .The nanocomposites were characterized by X-ray fluorescence (XRF), infrared spectroscopy (FTIR), thermogravimetry (TGA) and Field Emission Gun Scanning Electron Microscopy (FEG SEM) with an energy dispersive x-ray spectroscopy (EDS) detector. The produced nanocomposites showed well-dispersed SiC incorporation in the PMMA matrix. The results pointed that the surface treatment on SiC fillers was successful on enhancing the interaction between the organic matrix and the inorganic filler.

Abstract This is a study of the preparation and characterization of polymeric-magnetic nanoparticles. The nanoparticles used were magnetite (Fe3O4) and the chosen polymers were alginate and chitosan. Two types of samples were prepared: uncoated magnetic nanoparticles and magnetic nanoparticles encapsulated in polymeric matrix. The samples were analyzed by XRD, light scattering techniques, TEM, and magnetic SQUID. The XRD patterns identified magnetite (Fe3O4) as the only crystalline phase. TEM analyses showed particle sizes between 10 and 20nm for magnetite, and 15 and 30nm for the encapsulated magnetite. The values of magnetization ranged from 75 to 100emu/g for magnetite nanoparticles, and 8 to 12emu/g for coated with chitosan, at different temperatures of 20K and 300K. The saturation of both samples was in the range of 49 to 50KOe. Variations of results between the two kinds of samples were attributed to the encapsulation of magnetic nanoparticles by the polymers.

In the present study, poly (ethylene terephthalate)-based composites were produced and characterized. These composites were composed by poly (ethylene terephthalate) (PET) reinforced with geopolymer concrete waste (GCW). Both untreated (U-GCW) and treated with oleic acid (OA) geopolymer concrete waste (T-GCW) were used in the production of the composites. The PET/GCW ratios used for either treated or untreated GCW bodies were 80/20 (wt%), 60/40 (wt%) and 50/50 (wt%). Chemical compositions were assessed by X-ray fluorescence spectroscopy (XRF), crystallinity by differential scanning calorimetry (DSC), thermal stability by thermogravimetry (TGA), microstructure by field emission gun scanning electron microscopy (FEG-SEM) with energy dispersive X-ray spectroscopy (EDS), and mechanical properties were assessed by compression tests. Fourier transform infrared spectroscopy (FT-IR) was used to check the efficiency of the treatment with OA, as well as the interaction between PET and GCW. The T-GCW PET composites showed better thermal, physical, and mechanical properties, for non-structural applications, when compared to U-GCW.

O objetivo deste estudo foi avaliar a resposta biológica do tecido subcutâneo de camundongos à implantação de um novo biovidro à base de óxido de nióbio e óxido fosforoso. A morfologia do material foi analisada por microscopia eletrônica de varredura com espectroscopia de raios X por dispersão de energia (MEV/EDX) e a resposta tecidual foi avaliada após implantação de 30mg do biovidro no tecido subcutâneo da região dorsal de camundongos Balb/c (n=15), segundo ISO 10993-6. Após o período de 1, 3 e 9 semanas, os animais foram sacrificados e as necrópsias fixadas em formol tamponado pH 7,2 e submetidas ao processamento clássico para inclusão em parafina. Contudo, nenhum processo convencional de desmineralização de ossos e biomateriais cerâmicos foi capaz de desmineralizar o material. Alternativamente, o material obtido foi reprocessado e incluído em resina para corte em micrótomo de impacto. O estudo histopatológico considerou para análise: reação inflamatória (intensidade de células polimorfonucleares, mononucleares e células gigantes multinucledas das do tipo corpo estranho) e processo de reparo (tecido de granulação e fibrose). A análise do biomaterial no MEV/EDS demonstrou partículas irregulares com ampla variação dimensional e presença de nióbio, fósforo, cálcio, carbono e oxigênio. A análise histológica mostrou moderado infiltrado inflamatório composto de células mononucleares na semana 1, a qual desapareceu nos períodos subsequentes. Após 3 e 9 semanas, vasos sanguíneos foram observados com presença discreta de células gigantes multinucleadas tipo corpo estranho contendo partículas de biovidro de nióbio. Mesmo após 9 semanas, não se observou presença de cápsula fibrosa ao redor do material. Em nenhum momento, verificaram-se focos de necrose nem sinais de degradação das partículas. Baseado nestes resultados preliminares foi possível concluir que o material testado é biocompatível e não-bioabsorvível. A comparação deste biovidro contendo nióbio, especialmente implantado intra-ósseo, permitirá avaliar seu real potencial uso como enxerto ósseo.

The aim of this study was to evaluate the biological response to the implantation of a new biocompatible glass based on niobium oxide and phosphorus oxide. Scanning electron microscopy with energy dispersive spectroscopy evaluated the morphology of the material (SEM/EDS) and the tissue response was evaluated by implantation of 30mg of biocompatible glass on subcutaneous tissue of Balb/c mice (n=15) as ISO 10993-6. After the period of 1, 3 and 9 weeks, the animals were killed and the necropsies were fixed in buffered formalin pH 7.2 and processed for inclusion in paraffin after demineralization step in Allkymia solution; however, no demineralization conventional procedure for bone and ceramics biomaterials was sufficient to decompose the material. Alternatively, the material was processed for inclusion in resin for being cut by high impact microtome. The histopathological study considered inflammatory reaction (intensity of polymorphonuclear, mononuclear and giant multinuclear foreign body cells) and repair process (granulation tissue and fibrosis) for evaluation. SEM/EDS analysis showed irregular particles with wide size variation and presence of niobium, phosphorus, calcium and oxygen. Despite of the presence artifacts included during the histolopatological processing, microscopic analysis showed moderate inflammatory infiltrate with the presence of mononuclear cells in week 1, that disapeared in the next implantation periods. After 3 and 9 weeks, blood vessels were observed, with discrete presence of foreign body giant multinuclear cells containing particles of niobium biocompatible glass. Even after 9 weeks, no fibrous capsules were observed around the granules of material. Necrosis foci and particles degradation signs were not detected in no one experimental period. Based in these preliminary results, it was possible to conclude that the tested material is biocompatible and not bioabsorbable. The comparison of this biocompatible glass containing niobium, specially grafted into intraosseous sites, will allow the evaluation of its real potential use as bone graft.

In the present study, mechanical properties of porous glass reinforced hydroxyapatite bioceramics were assessed by microhardness, bending and compression tests and fracture toughness determination. Porous discs were produced by a dry method using wax spheres as pore formers. Green bodies were sintered and the final microstructure of the composites consists of hydroxyapatite, alpha and beta tricalcium phosphate (alpha and <FONT FACE=Symbol>b</font>-Ca3(PO4)2)due to the reaction between the glassy phase and the hydroxyapatite matrix. The results of the mechanical tests showed that the glassy phase yielded higher fracture toughness and bending strength when comparing with literature data for single hydroxyapatite. There is a compromise between mechanical properties and the porosity level for bioceramics: for example, according to Weibull statistics for composites with 65% porosity the maximum bending stress level is 0.2 MPa for 100% survival probability whereas this stress level increases to 2.5 MPa for composites with 40%. However, only the 65% porosity composite samples seem to have the complete adequate morphology for bone ingrowth.