Dispersing carbon nanotubes in phenolic resin using an aqueous solution

Abstract

A capacidade de controlar a dispersão de nanotubos de carbono (CNT) em polímeros é considerada ponto chave para a maioria das aplicações de compósitos de nanotubo/polímero. A dispersão de nanotubos de carbono em água com diferentes surfactantes, assim como sua incorporação em resinas fenólicas, foi investigada. Ultrasonicação de suspenções líquidas foi usada para preparar dispersões estáveis. A fim de se avaliar o melhor surfactante a ser usado, espalhamento de luz e espectroscopia UV-Visível foram empregados. A estrutura de CNT reforçada de resina fenólica foi analisada em função da concentração e tipo de surfactante, potência e tempo de sonicação. A influência da dispersão pelo uso das propriedades de transição de temperatura vítrea também foi avaliada, sendo obtida por análise mecânica dinâmica e energia de impacto.The ability to control the carbon nanotube (CNT) dispersion in polymers is considered the key to most applications of nanotube/polymer composites. The carbon nanotube dispersion into water with different surfactants, as well as its incorporation into phenolic resins, was investigated. Ultrasonication of liquid suspensions was used to prepare stable dispersions. In order to evaluate the best surfactant to be used, light scattering and UV-Visible spectroscopy were employed. The structure of CNT reinforced of phenolic resin was analyzed in function of the concentration and type of surfactant, sonication power and time. It was also evaluated the influence in the dispersion by using the glass temperature transition properties being obtained by dynamic mechanical analyses and impact energy. Keywords: carbon nanotubes, polymeric composites, phenolic resin IntroductionPolymer composites based on carbon nanotubes (CNTs) have attracted tremendous attention during these last years due to the impressive mechanical properties of CNTs, including high modulus value (around 1TPa), strength of 50-200 GPa, failure strain of up to 15% and electrical conductivity ranging from semiconducting to metallic, depending on their structure. [1][2][3][4][5] The interaction between functional groups of the compatibilizer and carboxyl or amine groups of multi wall carbon nanotubes (MWCNTs) stabilized the morphology and improved the interfacial interaction between MWCNTs and the thermoset matrix. 6,7 In general, the nanoscale dispersion of MWCNTs in polymeric matrix is achieved by strong hydrogen bonding between hydroxyl groups of the MWCNTs and polymer groups. Therefore, despite the extremely high strength of individual CNT shells, the weak shear interactions between adjacent shells and tubes lead to significant reductions in the effective strength of multi-walled carbon nanotubes. [8][9][10][11][12] This is responsible for the carbon nanotube bundles down to only a few GPa. [8][9][10][11][12] Nowadays, phenolic resins are indeed irreplaceable materials for selective high-technology applications, offering high reliability under severe conditions. Because of its excellent ablative properties, structural integrity, thermal stabili...

Evaluation of Techniques for Determination of Hydroxyl Value in Materials for Different Industrial Applications

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The Separation Power of Nanotubes in Membranes: A Review

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Effects of carbon nanotube fillers dispersion on mechanical behavior of phenolic/carbon nanotube nanocomposite

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