Processo de obtenção de pré-impregnados poliméricos termoplásticos via moldagem por compressão a quente

Nogueira, Clara Leal; Marlet, José M.; Rezende, Mirabel Cerqueira

doi:10.1590/s0104-14281999000300006

Cited by 10 publications

(7 citation statements)

References 5 publications

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“…Aromatic imide thermoplastic polymers, such as PEI, have been candidates for a variety of applications due to its excellent properties, such as flexibility, high glass transition temperature, excellent thermal stability/fire retardance, and ultraviolet radiation resistance. [24][25][26][27] Many studies have reported that only small addition of CNT in polymers can improve the thermal stability of composites significantly, resulting in an increase of thermal decomposition temperatures by about 5-10 C. [28][29][30] In addition, there are several models that explain the thermal decomposition of solids based on different theoretical concepts and empirical studies. In this study, the integral model of O-W-F was chosen because it is a widely used method in the thermal decomposition of polymeric materials.…”

Section: Resultsmentioning

confidence: 99%

Thermal decomposition kinetic study of multiwalled carbon nanotube buckypaper-reinforced poly(ether-imide) composites

Ribeiro

Santos

et al. 2017

Journal of Thermoplastic Composite Materials

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Poly(ether-imide) (PEI)-based composites filled with multiwalled carbon nanotubes in a dispersed form (1.0 wt%) and as buckypaper (BP) (25 wt%) have been prepared by mixing solution and hot compression molding technique, respectively. Vacuum filtration technique with the aid of water-based surfactant Triton X-100 was employed to produce BP sheets. The thermal stability of the composites was evaluated by thermogravimetric analysis and revealed a strong increase in thermal degradation temperature when BPs were used as nanofiller. Ozawa-Wall-Flyn model was used to determine the kinetic parameters. It was observed an increase in activation energy as the nanotubes concentration rise, suggesting the formation of more thermally stable systems. In addition, half-life time as function of temperature demonstrated that BP-based composites could operate for 3200 years at 200 C. These results concluded that carbon nanotube BP could contribute to improve significantly the thermal stability of PEI matrix.

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Section: Resultsmentioning

confidence: 99%

Thermal decomposition kinetic study of multiwalled carbon nanotube buckypaper-reinforced poly(ether-imide) composites

Ribeiro

Santos

et al. 2017

Journal of Thermoplastic Composite Materials

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“…Esta técnica garante compósitos com boa qualidade superficial e permite o uso de reforços com diferentes geometrias. Este método é principalmente utilizado no processamento de polímeros termorrígidos, como as resinas fenólicas, melamínicas, epoxídicas e as borrachas [1,2]. No caso da moldagem por compressão a quente, grandes esforços são utilizados na prensagem do material na cavidade, associados às temperaturas na faixa de 100 a 300 °C.…”

Section: Introductionunclassified

Comparação Microestrutural De Dois Aços Para Utilizaçâo Em Moldes De Fabricação De Compósitos

Silva¹,

Filho²,

Silva³

et al. 2017

Anais Do Enemet - Encontro Nacional De Estudantes De Engenharia Metalúrgica, De Materiais E De Minas

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ResumoOs compósitos poliméricos com fibras naturais são geralmente fabricados com a técnica de moldagem por compressão a frio ou a quente, na qual as fibras são as compactadas com resina em um molde. Em geral, a matriz deve ser feita de um aço resistente à fratura, à fadiga e dureza adequada, pois grandes esforços são utilizados na prensagem do material entre 100 a 300°C. Neste contexto, o objetivo deste trabalho foi avaliar a influência da temperatura na dureza dos aços SAE 8620 e SAE 8640. Amostras foram submetidas ao tratamento térmico de têmpera a 900 o C e revenimento na faixa de 150 a 650ºC. Posteriormente foram lixadas e polidas conforme os métodos convencionais de preparação metalográfica. Na revelação da microestrutura utilizou-se o reagente Nital 2%. Para avaliar a influência da temperatura foram feitas medidas de dureza Rockwel C e análises microestruturais das amostras. Os resultados mostraram que os materiais apresentam uma microestrutura típica de martensita revenida após têmpera e revenido. No entanto, a dureza é superior a 45 RC somente para o aço SAE 8640 até revenimento de 350°C. Conclui-se, portanto, que apenas o aço SAE 8640 é adequado para fabricação de moldes para moldagem a quente de compósitos poliméricos. Palavras-chave: Aço SAE 8620; Aço SAE 8640; Curva de revenimento; Conformação de compósitos. MICROSTRUCTURAL COMPARISON OF TWO STEELS FOR USING IN COMPOSITES CASTING MOLDS AbstractThe natural fiber polymeric composites are usually manufactured by hot or cold compression casting technique, which the fibers are impregnated with a resin in a mold. In general, the matrix must be set up of a steel with fracture, fatigue and hardness adequate resistance, because huge mechanical stresses are used at material compression between 100 and 300°C. Therefore this article has as objective evaluate the temperature influence in the SAE 8620 and SAE 8640 steels hardness. Samples were submitted to quenching at 900°C and tempering in the range of 150 to 650°C. Posteriorly it were sanded and polished according metallographic preparation standard methods. In the microstructure revelation Nital 2% reagent was used. To evaluate the temperature influence Rockwel C hardness measures and microstructural analysis were done with the samples. The results have shown that the materials exhibit an typical tempered martensite microstructure after quenching and tempering. However, hardness is greater than 45 RC up to 350°C only for SAE 8640. It's concluded, consequently, that only the SAE 8640 steel is suitable for hot casting of polymeric composites.

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“…In general, thermoplastic composites with continuous fibers are produced with less processing cycles, and can be hot pressed, thermoformed, pultruded, consolidated in autoclave or by automated methods on multiple complex shapes of large size [14][15][16][17][18][19][20] . Besides, they can be welded to other structures by electrical resistance, ultrasonic and induction technologies, for example [21][22][23][24][25] .…”

Section: Introductionmentioning

confidence: 99%

Fractographic and rheological characterizations of CF/PP-PE-copolymer composites tested in tensile

et al. 2017

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Processo de obtenção de pré-impregnados poliméricos termoplásticos via moldagem por compressão a quente

Cited by 10 publications

References 5 publications

Thermal decomposition kinetic study of multiwalled carbon nanotube buckypaper-reinforced poly(ether-imide) composites

Thermal decomposition kinetic study of multiwalled carbon nanotube buckypaper-reinforced poly(ether-imide) composites

Comparação Microestrutural De Dois Aços Para Utilizaçâo Em Moldes De Fabricação De Compósitos

Fractographic and rheological characterizations of CF/PP-PE-copolymer composites tested in tensile

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