Influência do SiO2 nas propriedades mecânicas da DGEBA

• Autor(a) principal: Costa, Zurel Siqueira
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFS
• Texto Completo: https://ri.ufs.br/handle/riufs/3502
• topic: SIO2; DGEBA; Polímeros; SiO2; DGEBA, polymers; CNPQ::ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA

In this study we used a different route, simple and economical: the dissolution of the SiO2 powder DGEBA with a hardener to base polymercaptan ( aradur 90 ). Analysis was performed micro hardness in different percentages of the concentration of SiO2. The hardness of multicomponent solid is approximately equal to the average hardness of the material composition and is also related to the fraction of crystalline phase present in these materials. Since the hardness of the material a decisive factor for its implementation, it is interesting to see how this property varies depending on the composition of multicomponent solid. Was used to DGEBA Araldite GY 279 and hardener aradur 90 provided by Huntsman. We prepared several samples with different concentrations of SiO2 (3%, 5%, 10%, 20%, 30%, 40% and 50%) compared to the total mass of Araldite-Aradur Mixtures spent 24 hours at ambient temperature and then became a cure at 100 ° C, 120 ° C, 140 ° C, 160 ° C and 180 ° C for 4 h in an oven at ambient pressure. For the determination of hardness, we used a Shimadzu micro hardness tester equipped with an indenter Vickers. Several tests were performed and it was observed that the micro hardness was a sharp increase with increasing temperature and the concentration of SiO2. This behavior is associated mainly to the oxidation of the surface and also due to the higher concentration of SiO2, forming a kind of composite with a thermosetting characteristics of high rigidity. There was a significant growth type reaching a 500 % increase in Vickers hardness between the sample with 50 % SiO2 and pure to a cure of 180 °C. Were also carried out measurements of elastic modulus and pure sample was obtained a score of 1.65 x107 Pa for the sample with 50 % had a value of 8x107 Pa. The growth of the elastic modulus accompanied the growth of the hardness, around 480 %. The presence of SiO2 in the epoxy resin causes a change in the mechanical properties of DGEBA and a concentration of 50% at 180 ° C for a cure for 4 h, a significant increase of the same. It was also observed at high homogeneity powder of silicon oxide to Araldite and Aradur These results indicate that the composite DGEBA/SiO2 can be a good candidate to be used in covering of metals, for example, duct that demand a good hardness.