Avaliação das propriedades mecânicas e morfológicas de compósitos de PEAD com pó de Pinus taeda e alumina calcinada

Abstract

ResumoNeste estudo foram desenvolvidos compósitos utilizando PEAD, pó de madeira (Pinus taeda), alumina calcinada e dois diferentes tipos de agentes compatibilizantes para avaliação das propriedades morfológicas e mecânicas dos mesmos. Para aumentar a interação entre a matriz polimérica e o pó de madeira foram utilizados 2% de polietileno graftizado com anidrido maleico em todas as formulações. Para efeito comparativo foi desenvolvida uma formulação com viniltrietoxisilano como compatibilizante para a alumina calcinada. O teor de cargas variou de 4% a 33% para os compósitos de carga única e mantiveram o percentual de 28% para os compósitos com as duas cargas. A interação entre a matriz polimérica e as cargas, proporcionada pelo agente compatibilizante anidrido maleico, foi observada nas micrografias da interface da matriz/carga. A utilização do silano não proporcionou efeito adicional nas propriedades mecânicas dos compósitos. Os compósitos isentos de alumina apresentaram maior resistência à tração, porém na resistência à flexão a presença da alumina contribuiu para o aumento desta propriedade provavelmente devido à pequena interação existente entre a interface do seu grão e a matriz polimérica. Palavras-chave: compósito, PEAD, pó de madeira, alumina calcinada, anidrido maleico. AbstractThis work aims at the evaluation of morphological and mechanical properties of HDPE composites developed with wood flour (Pinus taeda), calcined alumina and two different types of compatibilizing agents. In order to improve the interaction between the polymer matrix and wood flour 2% maleic anhydride-grafted polyethylene was used in all formulations. For comparison a formulation with triethoxyvinylsilane as compatibilizer for the calcined alumina was developed. The filler content ranged from 4% to 33% for the single filler composite while the percentage of 28% was kept as such for the two-fillers composites. The interaction between the polymer matrix and fillers, provided by the maleic anhydride compatibilizer agent, could be observed in the micrographs of the matrix / filler interface. The silane did not improve the mechanical properties of the composite. Free alumina composites showed higher tensile strength, but concerning flexural strength the presence of alumina contributed to increased values in this property. This was probably caused by the reduced interaction between the interface of its grain and the polymer matrix.

Thermal treatment of açaí (Euterpe oleracea) fiber for composite reinforcement

“…Figure 8 presents the stress vs. strain curves for the evaluated composites; the main results of these curves are summarized in Table 4. In general, when comparing the composites with neat PP, the addition of fibers provided a molecular interlock, increasing modulus and tensile stress, but decreased strain, as reported in the literature [4,7,9,14] . The mechanical behaviors of the composites prepared without the addition of PPgMA are quite similar, presenting statistically equal values of modulus and small differences in terms of tensile strength and elongation at rupture.…”

“…Coupling agents are macromolecules with polar and non-polar regions and are able to promote physical or chemical linkage between the vegetable fiber and polymer, respectively. Maleic anhydride [13] , polyethylene grafted with maleic anhydride (PEgMA) [14] , polypropylene grafted with maleic anhydride (PPgMA) [12] , diisocyanates [15] and silanes [16] are examples of coupling agents reported in the literature.…”

Avaliação das propriedades de um compósito de matriz polimérica de polipropileno reciclado reforçado com resíduo de madeira

“…Na Figura 7 são apresentados os resultados do ensaio de tração para o parâmetro módulo de elasticidade. Em seus estudos, Grison et al [28], realizaram testes mecânicos em compósito encontrando valores como 699,90 MPa para o módulo de elasticidade para a formulação PEAD com adição de 14% madeira e 2% de compatibilizante, e 507,90 MPa para o PEAD puro, valor que se aproxima dos resultados encontrados neste estudo para 100PP-I (595,00 MPa).…”

Mechanical and thermal properties of high-density polyethylene/alumina/glass fiber hybrid composites

“…9 For the selective improvement of the properties of polymers, fillers or reinforcements are added as a dispersed phase. 8,10 Inorganic fillers present better mechanical and thermal properties than organic ones and usually adhere better to the matrix phase, besides improving the thermal stability of polymers. 11 Addition of alumina (Al 2 O 3 ) results in better stiffness and thermal stability than the addition of metallic fillers and can be obtained in calcined or hydrated form, with micrometric or nanometric particle size.…”

“…11 Addition of alumina (Al 2 O 3 ) results in better stiffness and thermal stability than the addition of metallic fillers and can be obtained in calcined or hydrated form, with micrometric or nanometric particle size. 10,12,13 This inorganic filler is inexpensive and has been reported to increase the thermal stability of HDPE. 11,14,15 The addition of inorganic particulate fillers is also known to improve the elastic modulus of the material but at the cost of adversely affecting the impact resistance.…”