ABSTRACT
Composites with natural lignocellulosic fillers are being cited as a viable and sustainable alternative to conventional materials, as they combine lower costs with lower weight. In many tropical countries, such as Brazil, there is a considerable amount of lignocellulosic waste that is improperly discarded, which causes pollution of the environment. The Amazon region has huge deposits of clay silicate materials in the Negro River basin, such as kaolin, which can be used as fillers in polymeric composite materials. This work investigates a new composite material (ETK) made of epoxy resin (ER), powdered tucumã endocarp (PTE), and kaolin (K), without coupling agents, with the aim of producing a composite with lower environmental impact. The ETK samples, totaling 25 different compositions, were prepared by cold molding. Characterizations of the samples were performed using a scanning electron microscope (SEM) and a Fourier-transform infrared spectrometer (FTIR). In addition, the mechanical properties were determined via tensile, compressive, three-point flexural and impact tests. The FTIR and SEM results showed an interaction between ER, PTE, and K, and the incorporation of PTE and K reduced the mechanical properties of the ETK samples. Nonetheless, these composites can be considered potential materials to be used for sustainable engineering applications in which high mechanical strength is not a main requirement of the material.
ABSTRACT
The aim of this work was to study the stability and morphological properties of polystyrene latex containing kaolinite as a filler during the process of synthesis of nanocomposites viaemulsion polymerization. Nanocomposites with 1, 3, and 5 wt% of kaolinite were prepared. Latexes with 1 to 3 wt% of kaolinite were stable during the polymerization reaction. Hydrodynamic diameters of 93.68 and 82.11 nm were found for latexes with 1 and 3 wt% of kaolinite, respectively. The quantities of 1 to 3 wt% of kaolinite added during the reaction did not influence the reaction conversion curves or the number of particles. X-ray diffraction (XRD) and unconventional techniques of scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) showed the presence of exfoliated and intercalated structures of the kaolinite.
ABSTRACT
Date palm rachis fibers are rich in cellulose, relatively inexpensive, and readily available in Algeria. The aim of this study is to investigate the morphology, structure, mechanical and physicochemical characteristics of both vascular bundles and fiber strands extracted from date palm rachis. The difficulties encountered are associated to the extraction of the fibers without damaging them. The study focuses on the morphological and surface roughness analysis using optical and scanning electron microscopies (SEM), and a non-contact 3D profiler. The chemical, physical and thermal properties have been studied using Fourier-transform infrared (FTIR) spectroscopy, energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The mechanical properties were accessed by tensile tests and they were analyzed using two-parameter Weibull distribution.
Subject(s)
Phoeniceae/chemistry , Plant Vascular Bundle/chemistry , Cellulose/chemistry , Phoeniceae/ultrastructure , Plant Components, Aerial/chemistry , Plant Components, Aerial/ultrastructure , Plant Vascular Bundle/ultrastructure , Polysaccharides/chemistry , Surface Properties , Tensile StrengthABSTRACT
Este trabalho apresenta os resultados obtidos na simulação computadorizada da artroplastia total do quadril. Estuda o desgaste do polietileno do componente acetabular, utilizando o método de elementos finitos, com o objetivo de verificar a validade deste método de simulação. Foi simulado o desgaste do polietileno produzido pelo contato da cabeça femoral de cromo-cobalto, tendo o componente acetabular orientação espacial de 45° de inclinação lateral e anteversão neutra. Os resultados encontrados foram semelhantes àqueles observados em estudos clínicos.
