Substituição da fibra de vidro por fibra de bananeira em compósitos de polietileno de alta densidade: parte 1. Avaliação mecânica e térmica

Abstract

Resumo: A utilização de resíduo de fibra natural em substituição à fibra de vidro foi avaliada. Foram estudados compósitos de polietileno de alta densidade, HDPE, e fibra de bananeira com 10, 20, 30 e 40% (m/m) de fibra. Compósitos com fibra de vidro, mesma matriz polimérica e nas mesmas proporções, foram preparados para comparação. Os compósitos foram obtidos em extrusora dupla-rosca co-rotacional interpenetrante e os corpos de prova foram preparados por injeção. As propriedades mecânicas sob tração, flexão e impacto foram avaliadas. As propriedades térmicas foram analisadas por calorimetria diferencial de varredura (DSC) e análise termogravimétrica (TG). A incorporação de fibra de bananeira no HDPE resultou no aumento de cristalinidade do polímero. Houve, também, considerável aumento no grau de reforço mecânico nos compósitos pela incorporação da fibra natural. Foi possível comprovar a substituição da fibra de vidro pela fibra de bananeira em determinados percentuais, quando misturados ao HDPE, sem prejuízo às propriedades. A análise termogravimétrica dos compósitos mostrou que o início de degradação se deu numa faixa de temperatura intermediária entre a da fibra e a da matriz polimérica. Palavras-chave: Fibra de bananeira, polietileno de alta densidade, compósitos. Mechanical and Thermal Behavior of Composites Based on High Density Polyethylene and Banana Tree FiberAbstract: The use of banana tree fiber instead of glass fiber in polyethylene composites was evaluated. Composites of high density polyethylene with 10, 20, 30 and 40 wt. % of banana fiber were investigated. For comparison, composites with glass fiber, with the same polymeric matrix and proportions, were prepared. The samples were produced using an intermeshing co-rotating twin-screw extruder and injection molding. The mechanical properties investigated were the tensile, flexural and impact resistances of the composite. Thermal analyses were carried out by differential scanning calorimetry (DSC) and thermogravimetry (TG). The incorporation of fiber resulted in an increase in the composite degree of crystallinity. A considerable increase in mechanical reinforcement was achieved by incorporation of banana fiber in the composites. Thus, the replacement of fiberglass by banana fiber is possible when the components are used in specific proportions. Thermogravimetric analysis of the composites showed intermediate degradation temperatures between the values for banana fiber and polymeric matrix.

Biocomposites reinforced with natural fibers:thermal, morphological and mechanical characterization

“…In other words, the tenacity thereof in relation to other composites, including composite PP+GFPP is higher, they are less rigid, as shown by the modulus of elasticity in Figure 1-b, and absorb more impact energy. Similar behavior was encountered by GOMES et al [14] comparing banana fiber with glass fiber in high density polyethylene matrix; and, SANTOS et al [12] compared curauá fiber with glass fiber in Polyamide-6 matrix. The lower modulus of elasticity was obtained by natural fiber composites without additives PP+BS and PP+CC, being the lowest result obtained by the composite PP+BS attributed to poor adhesion of the babassu fibers to the polypropylene matrix, as can be observed in Figure 3-1b, from which the fiber could be easily removed.…”

Polyhydroxybutyrate Composites with Random Mats of Sisal and Coconut Fibers

“…This increase in crystallinity of composites may possibly be related to the action of the fibers as nucleating agents. These agents may be particulates or fibers dispersed in the matrix, thus the large number of small crystals are formed around them 57,58 .…”

Rotomolding and polyethylene composites with rotomolded lignocellulosic materials: A review

“…The use of lignocellulosic fibers as reinforcement is a good alternative because of their low density compared to inorganic material, 86 low cost, abundance in nature, and renewability. Adding lignocellulosic fibers to polyethylene results in lighter parts, meaning less polymeric material can be used and giving the final product a different appearance when compared to no fiber.…”