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Desenvolvimento e Caracterização de Compósitos de Polipropileno Reforçados com Cargas de Basalto
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Este trabalho tem por objetivo estudar a valorização de pó de basalto com diâmetro < 500 μm (PB), de pó de fibra de basalto com diâmetro 20-30 μm e comprimento <200 μm (FB) e escamas de basalto com 70-600 μm (EBF) e 100-800 μm (EB2) por incorporação de 5% (p/p), 10% (p/p) e 20% (p/p) destes materiais em compósitos de polipropileno. Para comparação foram utilizados compósitos de polipropileno com 5% (p/p), 10% (p/p) e 20% (p/p) de carbonato de cálcio com d50 de 2,7 μm (CC). No total foram extrudidos 15 compósitos. Durante o processo de extrusão foi observada grande variabili-dade na granulometria do grão. Verificou-se que este problema estava associado à dificuldade de con-trolo da temperatura da extrusora.
Foram injetados corpos de prova que forma utilizados nos ensaios de tração, ensaios de impacto, ensaios de flexão, ensaios de abrasão e também para a determinação da dureza, da densidade, do índice de fluidez, da hidrifobicidade, da absorção de água, da resistência dos compósitos a ácidos e bases, da resistência à degradação por exposição ao meio-ambiente e da resistência ao fogo dos compósitos.
Verificou-se que com o aumento da percentagem de carga, há um aumento da densidade, dureza, da rigidez, resistência à flexão e do modulo de flexão dos compósitos CC, PB, FB, EBF e EB2. O contrário foi observado para o índice de fluidez, a resistência à tração e a resistência à abrasão dos compósitos CC, PB, FB, EBF e EB2 com o aumento da quantidade de carga.
Os compósitos CC, PB, FB, EBF e EB2 apresentaram uma elevada resistência por exposição durante 24 h a ácido cítrico a 1% (p/p), hidróxido de sódio a 10% (p/p) e hipoclorito de sódio a 14% (p/p) de cloro ativo. Todos os materiais apresentaram uma elevada hidrofóbicidade com uma absorção de água inferior a 1%.
Foram realizadas ensaios de exposição direta ao meio-ambiente, por 77 dias, dos compósitos CC, PB, FB, EBF e EB2. Verificou-se um aumento significativo na descoloração dos compósitos PB, FB, EBF e EB2 com o aumento da quantidade de carga. Verificou-se ainda que a fragilidade dos compósitos CC, PB, FB, EBF e EB2 aumenta com o tempo de exposição.
O aumento da percentagem de todas as cargas dos compósitos resultou na diminuição da velocidade de queima, indicando que estas cargas podem, eventualmente, ser usadas como retardantes de chama naturais.
This work aims to study the valorisation of basalt powder with diameter < 500 μm (PB), basalt fibre powder with diameter 20-30 μm and length <200 μm (FB) and basalt scales with 70-600 μm (EBF) and 100-800 μm (EB2) by incorporation of 5% (w/w), 10% (w/w) and 20% (w/w) of these materials into polypropylene composites. For comparison were used polypropylene composites with 5% (w/w), 10% (w/w) and 20% (w/w) of calcium carbonate with d50 of 2.7 μm (CC). In total 15 composites were extruded. During the extrusion process a large variability in the grain size was observed. It was found that this problem was associated with the difficulty in controlling the extruder temperatures. Test specimens were injected and used in tensile tests, impact tests, bending tests, abrasion tests and also to determine the hardness, density, melt flow index, hydrophobicity, water absorption, resistance of composites to acids and bases, resistance to degradation by exposure to the environment and the fire resistance of the composites. It was verified that with the increase of the filler percentage, there is an increase in density, hardness, stiffness, flexural strength and flexural modulus of the composites CC, PB, FB, EBF and EB2. The opposite was observed for the melt flow index, the tensile strength and the abrasion resistance of the CC, PB, FB, EBF and EB2 composites with the increase of the amount of filler. The CC, PB, FB, EBF and EB2 composites showed high resistance by exposure for 24 h to 1% (w/w) citric acid, 10% (w/w) sodium hydroxide and sodium hypochlorite with 14% (w/w) active chlorine. All materials showed high hydrophobicity with a water absorption of less than 1%. Direct exposure tests to the environment were performed, for 77 days, of the composites CC, PB, FB, EBF and EB2. A statistically significant increase in the discolouration of the composites PB, FB, EBF and EB2 with the increase in the amount of filler was verified. It was also found that the brittleness of CC, PB, FB, EBF and EB2 composites increases with exposure time. Increasing the percentage of all fillers in the composites resulted in a decrease in the burning speed, indicating that these fillers can eventually be used as natural flame retardants.
This work aims to study the valorisation of basalt powder with diameter < 500 μm (PB), basalt fibre powder with diameter 20-30 μm and length <200 μm (FB) and basalt scales with 70-600 μm (EBF) and 100-800 μm (EB2) by incorporation of 5% (w/w), 10% (w/w) and 20% (w/w) of these materials into polypropylene composites. For comparison were used polypropylene composites with 5% (w/w), 10% (w/w) and 20% (w/w) of calcium carbonate with d50 of 2.7 μm (CC). In total 15 composites were extruded. During the extrusion process a large variability in the grain size was observed. It was found that this problem was associated with the difficulty in controlling the extruder temperatures. Test specimens were injected and used in tensile tests, impact tests, bending tests, abrasion tests and also to determine the hardness, density, melt flow index, hydrophobicity, water absorption, resistance of composites to acids and bases, resistance to degradation by exposure to the environment and the fire resistance of the composites. It was verified that with the increase of the filler percentage, there is an increase in density, hardness, stiffness, flexural strength and flexural modulus of the composites CC, PB, FB, EBF and EB2. The opposite was observed for the melt flow index, the tensile strength and the abrasion resistance of the CC, PB, FB, EBF and EB2 composites with the increase of the amount of filler. The CC, PB, FB, EBF and EB2 composites showed high resistance by exposure for 24 h to 1% (w/w) citric acid, 10% (w/w) sodium hydroxide and sodium hypochlorite with 14% (w/w) active chlorine. All materials showed high hydrophobicity with a water absorption of less than 1%. Direct exposure tests to the environment were performed, for 77 days, of the composites CC, PB, FB, EBF and EB2. A statistically significant increase in the discolouration of the composites PB, FB, EBF and EB2 with the increase in the amount of filler was verified. It was also found that the brittleness of CC, PB, FB, EBF and EB2 composites increases with exposure time. Increasing the percentage of all fillers in the composites resulted in a decrease in the burning speed, indicating that these fillers can eventually be used as natural flame retardants.
Descrição
Palavras-chave
Compósitos Basalto Polipropileno Pó de Basalto Pó de Fibras de Basalto Escamas de Basalto