Nanopartículas de sílica silanizada como compatibilizante em compósitos de fibras de sisal/polietileno

Abstract

ResumoFoi discutida neste estudo a influência de nanopartículas de sílica na compatibilidade entre fibras de sisal e polietileno de alta densidade, utilizados na preparação de compósitos. As fibras de sisal foram tratadas quimicamente e recobertas com nanopartículas de sílica por moagem mecânica. Os compósitos foram preparados por extrusão do polietileno com diferentes quantidades de fibras. Utilizou-se diferentes técnicas de caracterização para se obter as propriedades térmicas e a morfologia das fibras de sisal e dos compósitos, a influência das fibras de sisal e da sílica na cristalinidade do polietileno e o comportamento mecânico e a absorção de água do polietileno e dos compósitos. Foi observado que a as propriedades térmicas do polietileno não são afetadas pela presença das fibras e nanopartículas. Os diferentes tratamentos químicos e a presença de sílica nas fibras de sisal resultaram em propriedades mecânicas melhoradas e foram preponderantes para a diminuição da absorção de água nos compósitos, comparados ao polietileno. Palavras-chave: compósitos, compatibilização, nanopartícula de sílica silanizada, fibras de sisal, propriedades mecânicas. AbstractIn this study, the influence of silanized silica nanoparticles on the compatibility of composites prepared with sisal fibers and high density polyethylene is discussed. The sisal fibers were chemically treated and covered with silica nanoparticles by mechanical milling. The composites were prepared by extrusion of HDPE and different amount of fibers. The morphology and thermal properties of the sisal fibers and composites, the influence of sisal fibers and silica nanoparticles on crystallinity of HDPE, the mechanical behavior and water uptake of composites were evaluated by different techniques. It was observed that thermal properties of HDPE on composites were not changed by the presence of sisal fibers and silica nanoparticles. The different chemical treatments in sisal fibers and the presence of silica nanoparticles resulted in improved mechanical properties and were preponderant to the water uptake decrease in the composites, comparing with HDPE.

Production of biocomposites from the reuse of coconut powder colonized by Shiitake mushroom

“…In order to reduce environmental contamination, the green composite is produced from the mixture of vegetable fibers with EPS (Fernandes et al, 2017;Zhang et al, 2016). Alternatively, edible fungi and/or white rot fungi as: Agaricus bisporus (Román-Ramos; Luna-Molina; Bailón-Pérez, 2014), Pleurotus eryngii (Hemmati;Garmabi, 2012), P. ostreatus (Teixeira et al, 2018), Phaenerochaete chrysosporium (Ramirez-Chan et al, 2014) and Pycnoporus sanguineus (Teixeira et al, 2018) were used at production of composites through its reutilization as agricultural residues.…”

Production and mechanical evaluation of biodegradable composites by white rot fungi

“…to 50 %, which characterizes that the material becomes more fragile (Table 1). the presence of proteins associated with the fungal cell wall (Alexandre;Blanchet;Charpentier, 2000), which allows the use of the composite in several economic sectors, unlike the vegetable composites that are hydrophilic (Fernandes et al, 2017;Xie et al, 2018). In addition, fungal composites are also fire resistant (Hemmati;Garmabi, 2012), because the mycelium acts as a flame-inhibiting agent (Román-Ramos; Luna-Molina; Bailón-Pérez, 2014).…”

“…The green polymers appeared with an alternative to the plastic composites produced with substances derived from petroleum, in which the vegetal fibers make possible the obtaining of a material with physical and mechanical properties equal or similar to the EPS (Morais;Gadioli;Paoli, 2016;Fernandes et al, 2017;Xie et al, 2018), but with the advantage of being biodegradable (Landim et al, 2016). Thus, the use of coconut powder in the production of composites represents an innovative technological advance, because only a portion of the coconut shell is reused, after the consumption of water, in the manufacture of pots and substrate for production of seedlings.…”

The influence of fiber size on the behavior of the araucaria pine nut shell/PU composite

“…Fernandes et al [8] analyzed the influence of silica nanoparticles on the compatibility between sisal fibers and high density polyethylene. They observed that thermal properties of HDPE did not change because of the presence of sisal fibers and silica nanoparticles in the composite.…”

“…Load transfer from the polymer matrix to the fibers greatly depends on the matrix-fiber interaction [4] . Natural fibers are hydrophilic, while most polymer matrixes are hydrophobic [8,11] . As a result, the adhesion between those materials is compromised, decreasing the mechanical properties of the composite [5,6] .…”