Navegando por Palavras-chave "Carbon Nanotube"

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    Preparation and characterization of maleic anhydride grafted poly (hydroxybutirate-co-hydroxyvalerate) - phbv-g-ma
    (Univ fed sao carlos, dept engenharia materials, 2016) do Amaral Montanheiro, Thais Larissa [UNIFESP]; Passador, Fabio Roberto [UNIFESP]; de Oliveira, Mauricio Pinheiro [UNIFESP]; Duran, Nelson; Lemes, Ana Paula [UNIFESP]
    A compatibilizer agent was successfully produced by grafting maleic anhydride (MA) to poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) chains on a reactive processing by mechanical mixing, using a mixture of PHBV, MA and dicumyl peroxide (DCP) as initiator. The resulting PHBV grafted MA. (PHBV-g-MA) was characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and gel permeation chromatography (GPC), and its properties were compared to neat PHBV. FTIR showed an absorption band at 699 cm(-1) for PHBV-g-MA, related to CH group of grafted anhydride ring. The initial thermal degradation temperature of the compatibilizer agent was reduced when compared to neat PHBV. DSC analysis showed that after grafting MA onto PHBV the crystallization temperature was about 20 degrees C higher than neat PHBV, and the degree of crystallinity was increased. GPC analysis showed that MA when grafted onto PHBV led to a reduction of molecular weight and polydispersity.
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    Processamento do compósito de matriz de liga de alumínio AA6061 reforçada por nanotubos de carbono de paredes múltiplas por Equal Channel Angular Pressing (ECAP)
    (Universidade Federal de São Paulo (UNIFESP), 2019-06-21) Jimenez, Laila Ribeiro De Andrade Acevedo [UNIFESP]; Travessa, Dilermando Nagle [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    There has been increase in the need for materials that combine high mechanical resistance and low weight, foremost in aeronautical industry. Aluminum AA6061 alloys based metal matrix composites (MMC) reinforced by Multiple Walled Carbon Nanotube (MWCNT) are very interesting because they combine these properties. To optimize the distribution of the reinforcement along the matrix is indispensable to achieve the desirable properties in a composite. However, the MWCNT is formed of nanometric particles that tend to form clusters, and dissolve them to obtain a well-distributed reinforcement in the matrix can be a challenging step on the processing of the composite. ECAP (Equal Channel Angular Pressing) can be an efficient technique for producing microstructural refinement by promoting reinforcement distribution on the metal matrix when applied to composites. In this project, extruded bars of AA6061 composite reinforced with 2% MWCNT produced by powder metallurgy were successfully processed by 4 ECAP passes, using rout Bc and temperature of 200°C. ECAP produced microstructural modifications that reflected in hardness increase of 6,5%, mantainig ductility, when compared to its starting condition, as extruded (AE) bars, and yield stress of the processed composite values that were up to 388 MPa, under compression test.