Diffusion Foundations Vol. 14

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Authors: R.Q. da Costa Melo, A.G. Barbosa de Lima
Abstract: This chapter provides information in the area of vegetable fiber-reinforced polymer composites. It includes discussion about definition and classification of the composites and their constituents, composite manufacturing process and current application in different industrial sectors. Factors affecting the fiber/matrix interfacial adhesion and physic-chemical and mechanical properties of vegetable fiber-reinforced polymer composites are also revealed. The aim is to show for both academy and industry the viability on the use of vegetable fibers as reinforcement in polymer materials, because it offers many advantages and high potential in terms of unlimited availability, lightweight, reasonable cost, acceptable mechanical properties, and socio-economic and environmental benefits.
Authors: M.J. do Nascimento Santos, J.M.P.Q. Delgado, A.G. Barbosa de Lima
Abstract: This chapter focuses on the manufacturing of polymer composites reinforced by synthetic fiber with emphasis to the resin transfer molding technique (RTM). Herein, different related topics to foundations, classification, constituents and technological applications of polymer composites are presented. The problems associated to reinforcement and matrix interface and the manufacturing techniques of polymer composites are discussed. The study confirms RTM technique as a highly efficient process as compared with other manufacturing techniques of polymer composites.
Authors: A. Ferreira Tomaz, R. Cardoso Barbosa, M.R. de Oliveira Pinto, A.G. Barbosa de Lima, M.V. Lia Fook, M.A. Sabino Gutierrez
Abstract: Membranes are considered to be barriers that separates two phases and that totally or partially restricts the transport of one or several chemical species present in the phases. They have several applications, including food and pharmaceutical industry, sewage treatment, chemical and medical fields. In health area, must present characteristics such as bioactivity, biocompatibility, biodegradability, be non-toxic, anticarcinogenic and antimutagenic, aiming to protect human health, besides having properties related to mechanical resistance, permeability, among others that will depend on the application.
Authors: H. Lucena Lira, R.C. de Oliveira Lima, Iliana Oliveira Guimarães, G. Araújo Neves, R. Nóbrega Tavares, D. Silveira Lira, M.I. Rosas Neto, B. Silveira Lira
Abstract: Industrial wastes reuse becomes attractive to raw materials economy and to avoid environmental problems. The aim of this study is to develop and characterize tubular ceramic membranes using in their composition inorganic residues generated in the industries, such as, granite, alumina residue from calcination process and kaolin. Initially, it was performed the physical chemical and mineralogical characterization of the residues. Different formulations of ceramic masses have been studied with incorporation of residue, clay and additives for producing tubular membranes through the extrusion process. The membranes were characterized by SEM and flow measurements with distilled water. The membranes were applied to effluent treatment from textile and oil industry. The granite residue showed a high content of SiO2 and Al2O3 in its chemical composition and significant amount of iron and calcium oxides resulting from the granite processing. The granite residue presented average particle size of 13.98 µm. The residue from alumina process contain gibbsite and α-alumina, and average particles size of 15.68 µm. The residue from kaolin processing presented high content of quartz and alumina and average particles size of 29.0 µm. The tubular membrane produced with granite residue presented porosity from 17 to 30%, pores size in the range of 0.06 to 0.14µm and water flow from 10 (at 2 Bar) to 24 L/h.m2 (at 4 Bar). These membranes retained 100% of indigo particles and was effective in the separation of indigo. The membrane prepared with alumina residue presented porosity close to 58% , pore size of 0.96 µm and water flow from 68 to 80 L/h.m2 (at 2 Bar). These membranes were applied with successes in the separation of water from emulsion (100 ppm oil/water) with rejection above 96%. The membrane prepared with kaolin residue presented pore size from 0.16 to 0.22 µm, porosity from 41 to 44% and water flow from 53 to 70 L/h.m2. The ceramic membranes with industrial residues were successfully produced and applied in the treatment of industrial effluents.
Authors: E.A. Santos Filho, A. Florindo Salviano, B. Aline Araújo, K. Machado de Medeiros, Vanessa Nóbrega Medeiros, E. Maria Araújo, H. Lucena Lira
Abstract: In this work, polyamide 6 membranes (PA6) and hybrids with 1, 3 and 5% of montmorillonite clay (MMT) were obtained, adding potassium chloride (KCl) and calcium chloride (CaCl2). These different additives are intended to promote formation and increase of the pores in the microporous membranes. The membranes in the form of thin films were prepared by the phase inversion technique, leading to flat selective barriers. The MMT clay was characterized by X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). The membranes were characterized by XRD, FTIR, scanning electron microscopy (SEM), contact angle, water vapor permeation, flow measurements and yield. The clay XRD results showed characteristic peaks of bentonite containing accessory materials, as well as a peak at 5.93°, indicating the d001 basal interplanar distance of 14.95 Å of MMT. In the spectrum in the infrared region of the clay, it was observed the presence of hydroxyls inherent to the adsorbed water, as well as characteristic bands of Si-O-Si bonds and the octahedral layer of MMT. The viscosities of the solutions of PA6 and their hybrids with CaCl2 were higher compared to solutions containing KCl due the CaCl2 possess a bivalent ion with a high degree of hydration and a molecular mass higher than KCl. In addition, these salts promote formation of hydroxides that precipitate the particles of MMT, decreasing the viscosities with the increasing percentage of clay. By means of the X-ray diffraction, it was possible to perceive that the hybrid membranes with the inorganic salts suggest an exfoliated and/or partially exfoliated structure. From the results of the FTIR analysis the bands obtained in the PA6 membranes and its hybrids remained practically unchanged, as there was an increase in the clay content and the introduction of the inorganic salts. From the photomicrographs obtained by SEM, it was observed that the addition of clay in the hybrid membranes provided an increase in the number of pores with the gradual increase of the percentage of clay. While the addition of the inorganic salts (KCl and CaCl2) provided an increase in the pore size of the top surfaces of all membranes, by means of the contact angle, it was verified that the hybrid membranes presented smaller angles when compared to the PA6, probably, due to the superficial peculiarity of the clay to react with water. PA6 membranes with KCl and CaCl2 showed lower water vapor permeations as compared to hybrid membranes due to the increase in the size and quantity of pores presented on their top surfaces. The distilled water flow in the membranes initially showed a decrease and after 30 minutes a stability of the permeate flow due to a compression occurred in the membranes. The water-oil separation tests of the membranes with CaCl2, regardless of the pressure used, indicated a significant reduction of permeate oil with promising yields above 87% , presenting potential for the treatment of wastewater contaminated by oil.
Authors: C.A. Araújo Mota, C.J. Araújo, A.G. Barbosa de Lima, Tony Herbert Freire de Andrade, D. Silveira Lira
Abstract: Smart materials are a class of materials characterized by having a different behavior due to external stimulation, which can be mechanic, thermal, electric, or magnetic. This chapter approaches the different types of smart materials and their classification according to the material’s nature (fluid, ceramic, polymeric and metallic). Emphasis is given to the theoretical study of the metallic materials with shape memory, presenting the fundamentals, crystallographic study and the mathematical methods of phase transformation. Due to these metallic material’s unique features, shape memory effect and super elasticity, the usage in the production of composite structures has gained space. Such materials present several advantages if compared to traditional composites being subject of research for several industrial applications
Authors: P. Paula, J.M.P.Q. Delgado
Abstract: The use of gypsum plaster in building blocks, in Brazil, is still a restricted item, due to lack of knowledge on technology. Another factor that restricts the use of the blocks is the location of the deposits of gypsum, a material that gives rise to the plaster, which are located in the West of the State of Pernambuco, located far from the large consuming centers, potentially located in the southeast of the country. However, the interest in your study is determined by the annual consumption growth that reaches about 8% per year in Brazil. For the development of this study, in particular for Brazil, it is important to analysis the housing deficit in Brazil. The analysis indicates a clear need for new housing construction in the country. Preferably should be chosen simple constructive solutions, fast and easy to implement, without neglecting the comfort and durability. The use of local natural endogenous resources such as gypsum plaster, can be an attractive solution from an environmental point of view as well as economical. Brazil is a very large country with very different climates throughout its regions, so it was made a comprehensive study of the country's climate data and the constructive strategies adopted by NBR15220 and NBR 15575 standards, for each bioclimatic zone, to ensure the minimum comfort conditions. The hygrothermal analysis, reflected on the thermal comfort and night time ventilation in Brazilian gypsum plaster houses, was based on the adaptive model described in ASHRAE 55 and ISO 7730 standards for the evaluation of thermal comfort.

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