Avaliação de painéis produzidos a partir de resíduos sólidos para aplicação na arquitetura

O presente trabalho tem por objetivo o reaproveitamento de resíduos sólidos na preparação de painéis para uso na arquitetura. Para atingir as metas propostas, painéis foram preparados a partir de resíduos provenientes de embalagens cartonadas e plásticas, utilizando-se como elemento de reforço, resíduos lignocelulósicos (casca de amendoim e de arroz). A concentração e a natureza dos resíduos utilizados como matriz e como carga foram variadas gerando doze condições experimentais diferentes. As propriedades avaliadas dos painéis foram o módulo de ruptura, módulo de elasticidade, tração perpendicular à superfície, inchamento em espessura, absorção de água e densidade. Todos os ensaios foram realizados segundo as normas ASTM D1037 e EN 317, referente à chapa de partículas. Os resultados foram analisados segundo a norma ANSI A208.1 que especifica as propriedades de desempenho requeridas para as chapas de partículas. Os painéis foram classificados como de baixa densidade, podendo ser utilizados como forros, divisórias, revestimento decorativos e demais aplicações que requerem as mesmas propriedades físicas e mecânicas. Os painéis a base de embalagem plástica reforçados com casca de arroz apresentaram propriedades superiores do que os demais painéis produzidos. O elemento arquitetônico desenvolvido neste estudo representa um novo mercado potencial, podendo ser empregado no ambiente urbano e rural, atendendo ao conceito de produto ecoeficiente.This work aims to evaluate the utilization of solid residues in the preparation of panels for civil construction. Panels were prepared from residues based on multilayer packages and plastics, reinforced with lignocellulosics residues (peanut shells and rice hulls). Several blends were prepared with different ratios of components, resulting in twelve treatments. The following physical and mechanical properties were evaluated: modulus of elasticity, modulus of rupture, perpendicular tension to panel plan, water swelling and absorption. All tests were carried out according to the ASTM D1037 and EN 317 standards concerning particleboard. The results were analyzed considering the ANSI A208.1 standard, which specifies the required properties for particleboards. The treatments using rice hulls as reinforcement load and plastic packaging as matrix presented better performance than the treatment using peanut shells. The panels tested were classified according to ANSI standards as low density panels. The present study shows that this technology is feasible and the results presented lead to a promising use as architectonical element

Effect of wear conditions, parameters and sliding motions on tribological characteristics of basalt and glass fibre reinforced epoxy composites

Basalt fibre is a promising mineral fibre that has high potential to replace synthetic based glass fibre in today’s stringent environmental concern. In this study, friction and wear characteristics of glass and basalt fibres reinforced epoxy composites were studied and comparatively evaluated at two test stages. The first stage was conducted at fixed load, speed and distance under three different conditions; adhesive, abrasive and erosive wear, wherein each composite specimens slide against steel, silicon carbide, and sand mixtures, respectively. The second stage was conducted involving different types of adhesive sliding motions against steel counterpart; unidirectional and reciprocating motion, with the former varied at pressure—velocity (PV) factor; 0.23 MPa·m/s and 0.93 MPa·m/s, while the latter varied at counterpart’s configuration; ball-on-flat (B-O-F) and cylinder-on-flat (C-O-F). It was found that friction and wear properties of composites are highly dependent on test conditions. Under 10 km test run, Basalt fibre reinforced polymer (BFRP) composite has better wear resistance against erosive sand compared to Glass fibre reinforced polymer (GFRP) composite. In second stage, BFRP composite showed better wear performance than GFRP composite under high PV of unidirectional sliding test and under B-O-F configuration of reciprocating sliding test. BFRP composite also exhibited better friction properties than GFRP composite under C-O-F configuration, although its specific wear rate was lower. In scanning electron microscopy examination, different types of wear mechanisms were revealed in each of the test conducted

Evaluation of Phormium Cookianum Fibers as Reinforcements for Polypropylene-based Composites

Due to the abundance of vegetable fibers from the large variety of existing plant types, many of them have not yet been explored in terms of mechanical behavior as composite reinforcements. Most of the natural fibers composites are based in a few crop fibers leaving a large number of species without a comprehensive study. This work evaluates the tensile strength of fibers from Phormium cookianum. Scanning electron microscopy images were taken on the fiber surface after the mercerization process, as well as in the composite. Through these results, it can be identified that the damage caused to the surface of the fibers may directly influence the adhesion that occurs at the interface with the polymer. In general, the composites produced here have good mechanical properties with a low cost of production. On this basis, this product has the potential to replace panels, boards, injection and molded parts

Maximizing the utility of bio-based diisocyanate and chain extenders in crystalline segmented thermoplastic polyester urethanes: effect of polymerization protocol

High molecular weight semi crystalline thermoplastic poly(ester urethanes), TPEUs, were prepared from a vegetable oil-based diisocyanate, aliphatic diol chain extenders and poly(ethylene adipate) macro diol using one-shot, pre-polymer and multi-stage polyaddition methods. The optimized polymerization reaction achieved ultra-high molecular weight TPEUs (>2 million as determined by GPC) in a short time, indicating a very high HPMDI diol reactivity. TPEUs with very well controlled hard segment (HS) and soft segment (SS) blocks were prepared and characterized with DSC, TGA, tensile analysis, and WAXD in order to reveal structure property relationships. A confinement effect that imparts elastomeric properties to otherwise thermoplastic TPEUs was revealed. The confinement extent was found to vary predictably with structure indicating that one can custom engineer tougher polyurethane elastomers by "tuning" soft segment crystallinity with suitable HS block structure. Generally, the HPMDI-based TPEUs exhibited thermal stability and mechanical properties comparable to entirely petroleum-based TPEUs. (C) 2014 Elsevier Ltd. All rights reserved

Lignases Production and Partial Purification of Mnp from Brazilian Fungal Isolate in Submerged Fermentation

The potential of ligninases as a green tool for effective valorization of lignin can be shown through enzymatic cocktails containing different lignin degrading enzymes. The present study deals with the screening of potential fungal strains useful for the liquefaction of bark containing lignin. Three different local isolates (Pleurotus ostreatus POS97/14, Pycnoporus sanguineus and the local isolated fungal strain) were selected out of ten different strains for ligninases production. Maximum production of enzymes was observed in the local isolated fungal strain after ten days in submerged fermentation. The isolated fungal strain produces ligninases mainly for manganese peroxidase (MnP). The enzyme oxidized a variety of the usual MnP substrates, including lignin related phenols. Furthermore, the partial purification for MnP was determined by FPLC and the molecular weight was evaluated by SDS-PAGE.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Determination and electro-remediation of sulfamethazine using carbon nanotubes and silver nanoparticles as electrode modifiers

This paper discusses the development of a glassy carbon electrode (GC) for the determination and electro-remediation of sulfamethazine (SMZ) in natural waters using multi-walled carbon nanotubes (MWCNT) and silver nanoparticles (AgNPs) as electrode modifiers. The SMZ is an antibiotic found in surface and groundwater that can cause impacts for the environment and the population even at low concentrations. Therefore, it is essential to develop innovative approaches for the SMZ determination and degradation. The proposed GC electrode modifier was characterized demonstrating that the silver nanoparticles was incorporated onto the MWCNT. Voltammetric parameters of the SMZ oxidation process were optimized to improve the response in the analysis. The linearity obtained was from 0.3 to 5.0 µmol L−1, and the limit of detection and limit of quantification obtained was 0.19 µmol L−1 and 0.63 µmol L−1, respectively. This electrode was used for SMZ quantification in natural waters and interferents were used in a selectivity study. Finally, the GC/MWCNT-AgNPs was applied for the remediation of SMZ using chronoamperometry with +1.5 V for 2.5 h, decreasing 62.04% of the antibiotic. As a result, MWCNT-AgNPs were found to be an excellent option for the effective determination and remediation of the SMZ.</p