Preparação e avaliação biocida de compósitos à base de resinas reticuladas contendo nanopartículas de prata

• Autor(a) principal: Oliveira, Rachel Ouvinha de
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/15686
• topic: Nanoparticles; silver; bactericidal; Nanopartículas; prata; bactericida; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::QUIMICA ORGANICA

In this study, three commercial cross-linked ion exchange resins with acid character based on styrene divinylbenzene were used: Amberlite®GT73 from Rohm and Haas Co. with thiol group, Lewatit ® VPOC1800 Bayer Co. and Amberlyst ® 15WET Rohm and Haas Co. both with sulfonic group. These commercial resins were chosen because they have a high ion exchange capacity, stability and good functional groups for the introduction of Ag+ ions. The resins were treated with hydrochloric acid to ensure its acidic functional groups and then to procedure the reduction of Ag+ ions. The silver ions were coming from solution of silver nitrate and the reduction was carried out in situ by hydroxylamine in the presence of protective agent 1:1 solution composed of 2-hydroxyethylcellulose and gelatin. Some parameters were changed during the reduction of Ag+ ions to Ag0, for example, the time of addition of hydroxylamine solution, the solution used for pH control, and conditions that the solution was left at rest after controlling the pH. After the incorporation of silver nanoparticles, both commercial resins and the final product were characterized by titration, fluorescence x-ray, thermal analysis, elemental analysis, swelling degree, X-ray diffraction, optical and electron microscopy. The evaluation of biocidal activity was performed using the viable plate count method and a strain of Escherichia coli ATCC® 25922TM at concentrations from 103 to 107 cells/mL. All composites showed significant bactericidal activity, and it is noted that the bactericidal action of the composites is related to the presence of silver in metallic form and characteristics such as size, shape and dispersion of particles in the polymer matrix. Tests were performed also with the commercial resins and it was verified that bacterial action could be attributed only to silver nanoparticles