Influência da proporção de partículas de reforço nas propriedades mecânicas de um compósito experimental

• Autor(a) principal: Andrade, Rodrigo Rocha
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/6733
• topic: Compósito reforçado com fibra; Partícula de carga; Matriz resinosa; Fiber reinforced composite; Particle loading; Resin matrix; ODONTOLOGIA::CLINICA ODONTOLOGICA

Previous studies show that there is effective interaction between silanized glass fiber and resin matrix formed by methacrylates; However, there is no information on the use of milled glass fiber and the resin incorporated as a filler particle in order to obtain better mechanical properties in composites for the manufacture of intraradiculares pins. The objectives of this study were to evaluate the influence of different types (barium silicate and / or glass fiber powder) and charged particle concentrations in flexural strength, resistance to diametrical and Knoop microhardness traction, an experimental composite composed of 47.5% loading of particles, 30 % glass fiber and resin matrix of 22.5% (BISGMA and TEGDMA (1: 1)); evaluate the morphology of the filler particles and their interaction with the experimental composite in scanning electron microscopy. For producing glass fiber powder, fibers were milled in a mortar grinder / pestle, and then six experimental groups (N = 10) were prepared, varying the ratio of the kind of charged particle: CONTROL - 47.5% barium silicate and 0.0% glass fiber powder; G7.5 - 40.0% barium silicate and 7.5% glass fiber powder; G17.5 - barium silicate 30.0% and 17.5% glass fiber powder; G27.5 - barium silicate 20.0% and 27.5% glass fiber powder; G37.5% - 10.0% barium silicate and 37.5% glass powder vibrates; G47.5% - 0.0% barium silicate and 47.5% glass fiber powder. Cylindrical samples (3 mm x 6 mm) were produced for the diametral tensile strength test, and samples in bar format (25 mm x 2 mm x 2 mm) for flexural and microhardness knoop throws. Resistance tests were performed at 0.5 mm / min on a universal testing machine (Instron 5965). The Knoop microhardness test was made 0.2 KHN (200 g) for 40 seconds at a hardness tester (Shimadzu HMV2). After verification of normality and homogeneity of data distribution with the Kolmogorov-Smirnov test, the data were submitted to ANOVA and Tukey tests (α = 0.05). Statistical analysis demonstrated (p = 0.001): flexural strength: CONTROL - 259.91 ± 26.01a; G7.5 - 212.48 ± 35.91b; G17.5 - 177.63 ± 24.88bc; G27.5 - 166.58 ± 30.84c; G37.5 - 92.08 ± 6.46d; G47.5 - 80.60 ± 17.89d; Diametral tensile strength: CONTROL - 31.05 ± 2.98a; G7.5 - 14.55 ± 3.70b; G27.5 - 12.65 ± 3.34bc; G17.5 - 8.62 ± 3.51cd; G47.5 - 8.04 ± 1.63d; G37.5 - 6.63 ± 2.85d; Knoop microhardness: CONTROL - 75.69 ± 12.19a; G37.5 - 67.62 ± 1.79ab; G27.5 - 65.72 ± 2.01b; G47.5 - 64.06 ± 1.61b; G7.5 - 62.79 ± 2.79b; G17.5 - 59.87 ± 2.33b. The gradual substitution a percentage of the barium silicate glass fiber powder in a glass fiber reinforced composite trial resulted in a decrease in the results of flexural strength, diametral tensile strength and Knoop hardness. Morphologically, glass fiber powder made up of particles with heterogeneous and larger than the particle of barium silicate. The interaction of the glass fiber powder to the resin matrix and fiber reinforcement have not proved effective.