Pre-impregnated carbon fiber/epoxy resin (CF/epoxy prepreg) gained its popularity for significant stress applications, especially in the aerospace industry, owing to its excellent resistance and low specific mass. However, these CF/epoxy prepregs have a tendency to crack propagation. A solution for the prepregs fragility is the addition of carbon nanotubes (CNTs), especially those functionalized with amino groups, reinforcing the material due to its exceptional mechanical properties. In this work, the influence of the carbon chain length of two different amino-functionalized CNTs from diverse backgrounds (commercial and laboratory growth CNTs) is studied. The nanofillers were added in CF/epoxy prepregs by dry spraying without solvent aid. CNTs' samples were characterized by X-ray photoelectron spectroscopy, Raman spectroscopy, transmission electron microscopy, and thermogravimetric analysis (TGA), while the composites were analyzed by TGA, dynamic-mechanical analysis, and field emission scanning electron microscopy. The various surface treatment occurred at different levels according to the CNTs background, and all samples exhibited a distinct behavior. These differences were also observed in the composites' thermomechanical performance: CNTs functionalized with larger carbon chain amine presented the best results, with an increase of almost 100% in the storage moduli (E'), confirming the efficiency of aminofunctionalized CNTs in the reinforcement of CF/epoxy prepregs.
<p>As indústrias siderúrgicas brasileiras geram, em média, 145 mil toneladas por mês de areia descartada de fundição (ADF) ou resíduos de areia de fundição (RAF), como um subproduto do processo de fundição, impactando meio ambiente, sociedade, as próprias siderurgias e aterros sanitários. Porém, por ser considerado um resíduo não perigoso e muito semelhante aos agregados minerais, seu reuso na construção civil se mostra como uma interessante alternativa, evitando os impactos do descarte, além de beneficiar financeiramente as infraestruturas construídas. Nesse contexto, este artigo objetivou a dedução de uma rota metodológica para contabilizar esta economia gerada e estimar, em termos de economia financeira e de bens ambientais, os benefícios gerados no Brasil e no município de João Pessoa, estado da Paraíba, como um estudo de caso. Dessa forma, uma equação foi obtida, abrangendo diversos aspectos da cadeia de produção e descarte de ADF/RAF, estimando economias da ordem de 500 milhões de USD anuais, além de redução de emissões de CO<sub>2</sub> equivalente ao consumo de mais de 10 mil veículos por ano; pelo reuso da ADF/RAF produzida no Brasil.</p>
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