SÍNTESE E CARACTERIZAÇÃO DE NANOCOMPÓSITOS POLIMÉRICOS REFORÇADOS COM VERMICULITAS

As propriedades de proteção de um material por um revestimento polimérico são enfraquecidas por mecanismos térmicos e químicos, onde a reação de corrosão é favorecida na interface entre o material protegido e o material protetor. Para isso, faz-se necessário o estudo de sínteses menos complexas e eficientes de materiais que atuem com essa finalidade. Este trabalho busca analisar o efeito das propriedades térmicas, mecânicas e morfológicas na resina epóxi, a partir da adição de argila vermiculita paraibana nos teores de 1 e 3% em massa numa matriz à base de resina epóxi, após o processo de organofilização das argilas, que se apresentam naturalmente hidrofílicas e sem afinidade à compostos orgânicos. Os resultados mostraram uma estabilidade na temperatura de degradação do nanocompósito e um impressionante aumento na temperatura de transição vítrea. Houve também uma melhora na resistência à tração em relação a resina não modificada, sugerindo a intercalação polímero/argila, estrutura essa, comprovada a partir da técnica de Microscopia Eletrônica de Varredura (MEV). ABSTRACTThe protective properties of a material by a polymer coating are weakened by thermal and chemical mechanisms, where the corrosion reaction is favored at the interface between the protected material and the protective material. For this, it is necessary to study less complex and efficient syntheses of materials that act for this purpose. This work aims at analyzing the effect of thermal, mechanical and morphological properties on the epoxy resin, from the addition of vermiculite paraibaan clay at 1 and 3% by mass in a matrix based on epoxy resin, after the organophilization process of the clays, which are naturally hydrophilic and have no affinity for organic compounds. The results showed a stability in the degradation temperature of the nanocomposite and an impressive increase in the glass transition temperature. There was also an improvement in the tensile strength in relation to the unmodified resin, suggesting the polymer / clay intercalation, a structure that was proven using the Scanning Electron Microscopy technique (SEM)

Development and characterization of composite materials for production of composite risers by filament winding

Industry has been challenged to provide riser systems which are more cost effective and which can fill the technology gaps with respect to water depth, riser diameter and high temperatures left open by flexibles, steel catenary risers (SCRs) and hybrid risers. Composite materials present advantages over conventional steel risers because composite materials are lighter, more fatigue and corrosion resistant, better thermal insulators and can be designed for improving the structural and mechanical response. This paper contains a study of the toughening mechanism of an epoxy resin under rubber addition by means of fractographic analysis and its relation with the fracture process and increase of strength of a composite riser employing this polymeric matrix. Initially, an epoxy resin system was toughened by rubber CTBN addition (10 wt. (%)) as a way of improving the flexibility of future risers. Mechanical and thermal analyses were carried out for characterizing the polymeric systems. Later, composite tubes were prepared and mechanically characterized. The influence of matrix toughening on the mechanical behavior of the tubes was also studied. Split-disk tests were used to determine the hoop tensile strength of these specimens. The results indicate that the matrix plays an important role in composite fracture processes. The adding rubber to the polymeric matrix promoted a simultaneous increase of stress and elongation at fracture of the tubes manufactured herein, which is not often reported. These results, probably, is function of better adhesion between fibers and polymeric matrix observed in the CTBN-modified composite rings, which was evidenced in the fractografic analysis by SEM after the split-disk tests