Caracterização mecânica e térmica de um polímero termorrígido modificado com fibra de buriti
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Data
2017-02-20
Autores
Rosa, Bruno de Paula [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Pensando na sustentabilidade, a introdução de fibras naturais em substituição às sintéticas no reforço de matrizes poliméricas, faz-se necessária entre outras coisas devido à preservação do meio ambiente, redução de custos, sem que comprometa a qualidade final do material. Esse projeto tem o objetivo de obter as características mecânicas e térmicas de materiais compósitos a base de resina epoxídica curada DGEBA/TETA com a adição de porcentagens específicas de fibras de buriti. A fibra escolhida foi o buriti, pela abundância no Mato Grosso do Sul, buscando um desenvolvimento sócio econômico para a região e a matriz escolhida foi a epóxi DGEBA/TETA por ser a resina mais utilizada no mundo. Foram utilizadas fibras com diâmetro de 0,17mm e comprimento de 30mm em porcentagens em massa de 1%,5%,10%,15% e 17,6% do total do compósito. A caracterização mecânica foi realizada através de ensaios de tração. Após a ruptura dos corpos de prova foi verificado com uso da Microscopia Eletrônica de Varredura (MEV),a formação de microvazios através dos ensaios de Termogravimetria (TGA) e Calorimetria Diferencial de Varredura (DSC) foram verificadas a degradação e temperatura de transição vítrea (Tg) dos compósitos. O compósito com a adição de 5% em massa de fibras apresentou um aumento de 11,98% (60,12 para 67,32 MPa) no limite de resistência a tração (LRT) e de 8,21% no módulo de elasticidade (E) (901,06 para 977,82 Mpa) em relação a resina pura, acima de 5% as propriedades permaneceram constantes. Já o Limite de Resistência à propagação de trincas (K1C) não apresentou alterações significativas ao se adicionar fibras a resina (permanecendo em torno de 1,19 MPa). Não houve alteração na transição vítrea, ficando em torno de 70ºC. Já o TGA verificou que a temperatura de degradação dos compósitos apresentou um valor intermediário entre a resina pura e a fibra pura.
Thinking about sustainability, the introduction of natural fibers instead of synthetic fibers in the reinforcement of polymer matrices, is necessary among other things due to the preservation of the environment, cost reduction without compromising the final quality of the material. This project aims to obtain the mechanical and thermal characteristics of composite materials based on cured DGEBA / TETA epoxy resin with the addition of specific percentages of buriti fibers. The fiber was buriti, due to the abundance in Mato Grosso do Sul, seeking a socioeconomic development for the region and the chosen matrix was the epoxy DGEBA / TETA as the most used resin in the world. Fibers with a diameter of 0.17mm and a length of 30mm were used in mass percentages of 1%, 5%, 10%, 15% and 17,6% of the total composite. The mechanical characterization was performed through tensile tests. After the rupture of the specimens was verified with the use of Scanning Electron Microscopy (SEM), the microgravity formation through the Thermogravimetry (TGA) and Differential Scanning Calorimetry (DSC) tests showed the degradation and glass transition temperature ( Tg) of the composites. The composite with the addition of 5% by mass of fibers presented an increase of 11.98% (60.12 to 67.32 MPa) at the tensile strength limit (LRT) and 8.21% in the modulus of elasticity ( E) (901.06 to 977.82 MPa) relative to pure resin, above 5% the properties remained constant. However, the Limit of Resistance to crack propagation (K1C) did not show significant changes when adding fibers to the resin (remaining around 1,19 MPa). There was no change in the glass transition, being around 70ºC. The TGA verified that the degradation temperature of the composites showed an intermediate value between the pure resin and the pure fiber.
Thinking about sustainability, the introduction of natural fibers instead of synthetic fibers in the reinforcement of polymer matrices, is necessary among other things due to the preservation of the environment, cost reduction without compromising the final quality of the material. This project aims to obtain the mechanical and thermal characteristics of composite materials based on cured DGEBA / TETA epoxy resin with the addition of specific percentages of buriti fibers. The fiber was buriti, due to the abundance in Mato Grosso do Sul, seeking a socioeconomic development for the region and the chosen matrix was the epoxy DGEBA / TETA as the most used resin in the world. Fibers with a diameter of 0.17mm and a length of 30mm were used in mass percentages of 1%, 5%, 10%, 15% and 17,6% of the total composite. The mechanical characterization was performed through tensile tests. After the rupture of the specimens was verified with the use of Scanning Electron Microscopy (SEM), the microgravity formation through the Thermogravimetry (TGA) and Differential Scanning Calorimetry (DSC) tests showed the degradation and glass transition temperature ( Tg) of the composites. The composite with the addition of 5% by mass of fibers presented an increase of 11.98% (60.12 to 67.32 MPa) at the tensile strength limit (LRT) and 8.21% in the modulus of elasticity ( E) (901.06 to 977.82 MPa) relative to pure resin, above 5% the properties remained constant. However, the Limit of Resistance to crack propagation (K1C) did not show significant changes when adding fibers to the resin (remaining around 1,19 MPa). There was no change in the glass transition, being around 70ºC. The TGA verified that the degradation temperature of the composites showed an intermediate value between the pure resin and the pure fiber.
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Palavras-chave
Compósitos, Fibras de buriti, Resinas epoxídicas, Propriedades mecânicas e térmicas, Composites, Buriti fibers, Epoxy resins, Mechanical and thermal properties