ABSTRACT
Engineering activities aim to satisfy the demands of society. Not only should the economic and technological aspects be considered, but also the socio-environmental impact. In this sense, the development of composites with the incorporation of waste has been highlighted, aiming not only for better and/or cheaper materials, but also optimizing the use of natural resources. To obtain better results using industrial agro waste, we need to treat this waste to incorporate engineered composites and obtain the optimal results for each application desired. The objective of this work is to compare the effect of processing coconut husk particulates on the mechanical and thermal behavior of epoxy matrix composites, since we will need a smooth composite in the near future to be applied by brushes and sprayers with a high quality surface finish. This processing was carried out in a ball mill for 24 h. The matrix was a Bisphenol A diglycidyl ether (DGEBA)/triethylenetetramine (TETA) epoxy system. The tests that were performed were resistance to impact and compression, as well as the linear expansion test. Through this work, it can be observed that the processing of coconut husk powder was beneficial, allowing not only positive improvements to the properties of the composite, but also a better workability and wettability of the particulates, which was attributed to the change in the average size and shape of particulates. That means that the composites with processed coconut husk powders have improved impact strength (46 up to 51%) and compressive strength (88 up to 334%), in comparison with unprocessed particles.
ABSTRACT
The use of natural lignocellulosic fibers has become popular all over the world, as they are abundant, low-cost materials that favor a series of technological properties when used in cementitious composites. Due to its climate and geographic characteristics, Brazil has an abundant variety of natural fibers that have great potential for use in civil construction. The objective of this work is to present the main concepts about lignocellulosic fibers in cementitious composites, highlighting the innovation and advances in this topic in relation to countries such as Brazil, which has a worldwide prominence in the production of natural fibers. For this, some common characteristics of lignocellulosic fibers will be observed, such as their source, their proportion of natural polymers (biological structure of the fiber), their density and other mechanical characteristics. This information is compared with the mechanical characteristics of synthetic fibers to analyze the performance of composites reinforced with both types of fibers. Despite being inferior in tensile and flexural strength, composites made from vegetable fibers have an advantage in relation to their low density. The interface between the fiber and the composite matrix is what will define the final characteristics of the composite material. Due to this, different fibers (reinforcement materials) were analyzed in the literature in order to observe their characteristics in cementitious composites. Finally, the different surface treatments through which the fibers undergo will determine the fiber-matrix interface and the final characteristics of the cementitious composite.
ABSTRACT
In this work, the study of the biomass application of a microphyte plant Slavinia auriculata Aublet in red ceramic was carried out. The waste comes from the phytoremediation process, used in sewage treatment plants. Characterization tests were carried out by chemical, mineralogical, dilatometry, thermal and mass spectrometry techniques, where it was possible to prove that biomass is compatible in its composition for application in ceramic materials and also has great potential to act as a source of energy. The production of specimens was carried out using an industrial clay mass and incorporating 0-10% of biomass in samples produced by pressing and burned at temperatures between 750 and 1050 °C. Properties of plasticity, firing shrinkage, apparent drying and firing density, water absorption, compressive strength and tensile strength in flexion were evaluated, where the feasibility of using up to 2.5% biomass in ceramics firing in 1050 °C s was proven. Although the results of water absorption at the firing temperature of 1050 °C have increased from 18.3% to 19.4% with the use of 2.5% of the residue, the results of tensile strength in flexion have reduced from 4.80 to 3.75 MPa and the results of compressive strength have reduced from 27.6 to 22 MPa, the values obtained meet international recommendations and are in accordance with the recommendations of the bibliography. Finally, an economic analysis of the application of biomass in ceramic materials was carried out, where it was observed that it was possible to save up to 5.04% with the use of the biomass under study, providing an annual savings of $ 2668.8 for the ceramic industry.
