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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Estudo de nanocompósitos poli(metacrilato de hidroxietila) / laponita para revestimento de sementes / Study of nanocomposites poly (hydroxyethyl methacrylate) / laponite for seed coating

Lima, Kelly Santana 28 February 2018 (has links)
Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The search for more productive seeds and with better transport and storage conditions has developed the interest of companies and researchers. In this section, nanotechnology, in particular, polymer / clay nanocomposites has proved to be an excellent alternative. By means of these nanomaterials it is possible to transport assets that allow the plant to better growth, productivity and germination rates, through the transport of fertilizers, agrochemicals or even essential micronutrients. The aim of this work was to synthesize and study nanocomposites polymer / clay; poly (hydroxyethyl methacrylate), pure laponite (pHEMA / Lap) and enriched with manganese micronutrients (pHEMA / LapMn). These materials aim to provide water and concomitantly provide nutrients to the seeds. The best formulation for the samples, amounts of polymer and clay was studied, and from this the micronutrient was incorporated into the formulation. The materials were characterized by absorption spectroscopy in the infrared region (FTIR), X-ray diffractometry (XRD) and thermogravimetry (TG). In addition, the water uptake capacity of the samples was evaluated. TG results showed an increase in thermal stability due to the interaction of the polymer chain with the clay. The XRD study showed that pure Lap and Lap Mn presented similar basal spacing to that found in the literature and that the nanocomposite had an exfoliated structure of the materials. The observation of the degree of swelling of the samples showed that the nanocomposites showed a capacity of water absorption 10% higher than the pure hydrogel. The seed coating affected the germination rate of the seeds, showing an optimization of this process. / A busca por sementes mais produtivas e com melhores condições de transporte e armazenamento tem desenvolvido o interesse de empresas e pesquisadores. Nesta vertente, a nanotecnologia, em especial, os nanocompósitos polímero/argila tem se mostrado uma excelente alternativa. Por meio destes nanomateriais é possível transportar ativos que possibilitem a planta melhor crescimento, produtividade e taxas de germinação, por meio do transporte de fertilizantes, agroquímicos ou até micronutrientes essenciais. Neste trabalho buscou-se sintetizar e estudar nanocompósitos polímero/argila; poli(metacrilato de hidroxietila) (pHEMA), laponita pura (pHEMA/Lap) e enriquecida com micronutrientes manganês (pHEMA/LapMn). Estes materiais tem por objetivo fornecer água e concomitantemente fornecer nutrientes para as sementes. Estudou-se qual a melhor formulação para as amostras, quantidades de polímero e de argila e a partir desta incorporou-se o micronutriente a formulação. Os materiais foram caracterizados por espectroscopia de absorção na região do infravermelho (FTIR), difratometria de raios X (DRX) e termogravimetria (TG). Além disso, a capacidade de absorção de água das amostras foi avaliada. Houve aumento da estabilidade térmica decorrente da interação da cadeia polimérica com a argila. O estudo por DRX mostrou que a Lap pura e a Lap Mn apresentaram espaçamento basal similar ao encontrado na literatura e que o nanocompósito apresentou estrutura esfoliada dos materiais. A observação do grau de intumescimento das amostras mostrou que os nanocompósitos apresentaram uma capacidade de absorção de água 10% superior à do hidrogel puro. O revestimento das sementes prejudicou a taxa de germinação das mesmas mostrando-se necessário uma otimização deste processo. / São Cristóvão, SE

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