Síntese e caracterização de nanocompósitos à base de poliuretano dispersos em água com argilas hidrofílica e organofílica

• Autor(a) principal: Garcia, Claudia Pacheco
• 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/1/15721
• topic: Polyurethane; aqueous dispersions; nanocomposites; clays; motmorillonite; non-polluting systems; Poliuretanos; dispersões aquosas; nanocompósitos; argilas; montmorilonita; formulações não-poluentes; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA

Nanostructured materials have been extensively studied, specially the systems formed by nanocomposites of polymers and clays. In this work, nanocomposites of polyurethane (NWPU's) were synthesized employing hydrophilic and hydrophobic (organophilic) montmorillonite clays (MMT). The monomers used in the synthesis were poly(propylene glycol) (PPG); hydroxyl-terminated polybutadiene (HTPB); dimethylolpropionic acid (DMPA), isophorone diisocyanate (IPDI) and hydrazine (HYD), as chain extender. The contents of HTPB and clay were varied. In the formulations, organophilic Cloisite 30B and hydrophilic Cloisite Na+ were added by varying from 1 to 5%. The organophilic Cloisite 15A was incorporated as 1% content only. The dispersions were characterized by means of solids content, particle size and viscosity. The cast films from dispersions were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XDR), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The thermal resistance and glass transition temperatures of the materials were determined by thermogravimetry (TG) and differential scanning calorimetry (DSC), respectively. The degree of water absorption and the mechanical behavior of the films were evaluated. The formation of nanocomposites based on water was confirmed by the absence of the XRD peak, characteristic of the pure non-delaminated clays. The micrographs obtained by SEM confirmed a homogeneous dispersion of clay in the polyurethane matrix. The films based on nanocomposites (NWPU's) exhibited mechanical properties superior to those obtained from the dispersions in where no clay was added (WPU's). The adhesiveness of the coatings, obtained from the application of the dispersions in many different surfaces, was visually evaluated. The characterization results showed that the formation of water-based polyurethane nanocompósitos (NWPU s) was achieved successfully, by employing organophilics and hydrophilic clays