Abstract Oil spills into water have been an environmental concern since the beginning of large-scale oil extraction. In this study, flexible open-cell polyurethane (PU) foams with added microcrystalline cellulose (MCC) were formulated and chemically modified with organosilane for use as an absorbent system for oil spill cleanup in water. The influence of cellulose concentration on mechanical properties and chemical treatment with organosilane was evaluated. The primary findings indicate that the surface treatment of the solid fraction of the foams was effective, as indicated by the contact angle, increasing the hydrophobicity of the samples. Because of the increased roughness of the PU solid fraction and the cellulose reactivity, the mechanical compressive strength and thickness of the organosilane layer increased with increasing MCC content. However, the higher the MCC content in the composition, the higher was the density, which reduced the sorption capacity of the samples.

Abstract This work studied the incorporation of organic acids as crosslinking agents and reaction time on the properties of poly(alcohol vinyl) (PVOH) hydrogels to act as scaffold systems to compounds incorporated into agriculture systems. PVOH hydrogels crosslinked with citric and L-malic acids were prepared, and the effects of heat-treatment time, and temperature on their swelling and hygroscopic performances were investigated by FTIR, thermal analysis and swelling. Both the swelling and rate of water uptake of hydrogels decreased with increasing heat-treatment time. While the swelling decreased with heat-treatment time, the chemical crosslinking shown in FTIR increased. DSC results indicated adsorbed water in the uncrosslinked PVOH and hydrogels, and the absorbed water changed the melting point and glass transition temperature. TGA analysis showed that the incorporation of organic acids brought thermal stability. The results obtained show effective crosslinking hydrogels by L-malic acids and possibilities to use in scaffold systems and controlled release. polyalcohol poly alcohol vinyl (PVOH Lmalic L malic prepared heattreatment heat treatment increased stability release

Abstract Poultry litter waste (PLW) is the main by-product generated by the Brazilian poultry industry. A sustainable approach for reusing this waste is the production of biochar to be further used aiming CO2 adsorption. In this work, biochars were produced by varying the N2 flow along the pyrolysis process of 150 (PLW-150) and 1000 (PLW-1000) mL min-1. PLW and biochars were characterized for their morphology, porosity, specific surface area, and CO2 adsorption capacity. From the biochars, carbon cryogels (CC) were produced aiming their use as CO2 adsorbents. The results of the cryogel adsorption test showed a CO2 adsorption capacity of 13.1±2.9 and 33.8±3.3 mg g-1 for the CC-PLW.150 and CC-PLW.1000 cryogels, respectively. Therefore, reusing this residue for cryogels production and its use in the CO2 adsorption signifies an attractive perspective to minimize the environmental damage caused by CO2 emissions.

RESUMO O descarte inadequado de pneus representa um grave problema ambiental, pois seu elevado tempo de decomposição, aliado ao seu descarte incorreto, o torna uma grande ameaça aos recursos naturais, causando contaminação de solos e rios, além de enfermidades provocadas pelo acúmulo de resíduos e água em seu interior, proliferando vírus e bactérias. Dentre as alternativas possíveis de reutilização deste resíduo é possível optar por sua incorporação em outros materiais, o que além de torná-lo um resíduo economicamente atrativo, possibilita que sejam desenvolvidas novas composições de materiais com propriedades diferenciadas. A proposta deste trabalho consiste na adição de resíduo de pneu em matriz de elastômero termoplástico SEBS (copolímero de estireno - etileno/butileno - estireno). Em um primeiro momento avaliou-se a influência do tamanho de grão do resíduo. Foram utilizados grãos de tamanhos de 12, 24 e 35 mesh. Após a realização de ensaios físicos, térmicos e mecânicos, que permitiram a escolha da melhor granulometria, variou-se a concentração de resíduo em 10, 20 e 30% em massa de SEBS. Os resultados mostraram que o composto desenvolvido com granulometria de 12 mesh, em concentração de 10% em massa de SEBS, mostrou-se a composição com melhores propriedades mecânicas, o que sugere sua vantagem em aplicação em pisos industriais.

ABSTRACT The inadequate disposal of tires represents a serious environmental problem, since its high decomposition time, together with its incorrect disposal, makes it a great threat to natural resources, causing contamination of soils and rivers, as well as diseases caused by to the accumulation of waste and water inside and the proliferating viruses and bacteria. Among the possible alternatives of reuse of this residue is its incorporation in other materials, which in addition to making it an economically attractive residue and allows the development of new compositions of materials with different properties. The purpose of this work is the addition of tires residue in SEBS thermoplastic elastomer matrix (styrene - ethylene / butylene - styrene block copolymer). In first step, the influence of the grain size of the residue was evaluated. Tires particles of 12, 24 and 35 mesh sizes were used. After physical, thermal and mechanical analysis, which allowed the choice of the best granulometry, the residue concentration was varied in 10, 20 and 30% by mass in SEBS matrix. The results showed that the compound developed with 12 mesh granulometry at a concentration of 10% by mass SEBS matrix showed the composition with better mechanical properties, which suggests its advantage in application on industrial floors.

ABSTRACT Polyvinyl chloride (PVC) is a very versatile polymer with many applications. Due to the easy incorporation of additives and plasticizers in this resin. The most used plasticizer for PVC is dioctyl phthalate (DOP), however its use has been restricted by several organizations because it presents potential toxicity. In this way, the objective of this work is to evaluate thermal, physical and dynamic-mechanical characteristics for a polymeric plasticizer alternative to DOP, polyisobutene base. As a method of comparison, the contents of the materials were kept constant, and only the plasticizer content of the samples was altered. Results indicated that the PVC compounds obtained satisfactory plasticizing results and that don’t have chemical transformations. In addition, the plasticizer evaluated has a higher thermal stability when compared to the compound with DOP, proving to be a promising result.

Abstract The accumulation of polymeric residues has been one of the most impacting environmental problems in recent human history, coming, above all, from disposable artefacts, such as plastic bags. Processing polyolefins with pro-oxidant additives is an alternative to favour the abiotic degradation process of macromolecules, including thermooxidation, so that the oxygenated fragments produced can be assimilated by microorganisms. The objective of this work was to evaluate the process of thermomechanical oxidative degradation of polyethylene (PE) during tubular extrusion of HDPE/LDPE films, without and with 1% of two different pro-oxidants, d2wTM and benzoin. The results of viscosimetric and MFI analyses indicated smaller chain sizes in the additivated films. The FTIR spectra and contact angles indicate a higher presence of polar functional groups in the samples with pro-oxidants. The surface morphological analysis by SEM indicated difference of PE homogeneity in the films. Benzoin, however, proved to be a better pro-oxidant than d2wTM.

RESUMO O uso de resíduos poliméricos na construção civil tem sido alvo de muitos estudos com o objetivo de reduzir o volume de plásticos pós-consumo no meio ambiente. Este trabalho concentra-se na viabilidade do uso de politereftalato de etileno (PET) e polipropileno (PP) como substituição parcial da areia no concreto. Os flocos de PET e PP pós-consumo foram utilizados como agregado leve para substituir parcialmente em 10% o volume de areia. O efeito da adição desses polímeros foi investigado em termos de propriedades físicas, mecânicas, de durabilidade e morfológicas do concreto. As propriedades físicas foram a absorção de água, teor de vazios e massa específica. As propriedades mecânicas das amostras foram medidas em termos de resistência à compressão e módulo de elasticidade. A durabilidade foi avaliada em termos de absorção de água por capilaridade e indicação elétrica do concreto para resistir à penetração de íons cloretos. A análise morfológica foi realizada pelo MEV e EDS. Curvas de DSC foram utilizadas para avaliar as propriedades térmicas dos flocos. O-teste de ângulo de contato também foi realizado. A adição parcial de polímeros de PET e PP reduziu a resistência à compressão em 20%, enquanto a redução do módulo de elasticidade foi de 16% para as amostras de PET e quase insignificante para as amostras de PP. Os resultados de durabilidade mostram que os polímeros contribuíram para aumentar a resistência das amostras à penetração de cloretos em 15% e 57%, para amostras de PET e PP, respectivamente, no entanto, houve um aumento no teor de vazios e na absorção de água. No ensaio de morfologia é possível observar uma menor adesão interfacial entre o PP e a massa cimenticia em comparação ao PET.

ABSTRACT The use of polymeric residues in the civil construction has been the target of many studies aiming to reduce the volume of post-consumer plastics in the environment. This work focuses on the viability to use polyethylene terephthalate (PET) and polypropylene (PP) as partial replacement to sand in concrete. PET and PP flakes from post-consumer packings were used as light aggregate to partially replace, individually, 10% in volume of sand. The effect of adding these polymers was investigated in terms of physical, mechanical, durability and morphological properties of the concrete. Physical properties were measured in terms of water absorption, voids content and specific mass. Mechanical properties were measured in terms of compressive strength and elasticity modulus. Durability properties were measured in terms of capillarity water absorption and electrical indication of the concrete to resist to chloride ion penetration. MEV and EDS were used to carry out morphological analysis. DSC curves were carried out to evaluate thermal properties of the polymeric flakes. Contact anlge test was also performed. The partial addition of PET and PP polymers reduced the compressive strength by 20%, whilst the reduction of the elasticity modulus was 16% for PET samples, and almost insignificant for PP samples. The durability results show that the polymers contributed to increase the resistance of the samples to chloride penetration by 15% and 57%, for PET and PP samples, respectively; however, there was an increase in the voids content and water absorption. In the morphological test it is possible to observe a lower interfacial adhesion between PP and the cementions paste in comparison to PET.

Abstract In this work, a bio-based adhesive is prepared from Protium heptaphyllum resin. The resin is first characterized by 1H and 13C nuclear magnetic resonance spectroscopy and the bioadhesive is then prepared using a simple mixture of the resin with linseed oil, catalyzed by cobalt octanoate, to induce crosslinking. The precursors and bioadhesive obtained are characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The NMR analysis shows the presence of groups of triterpenes, such as α- and β-amyrins, and diols, such as brein and maniladiol. Thermogravimetric analysis reveals that the resin has less thermal stability than the bioadhesive. Mechanical tests indicate that the bioadhesive has greater adhesion strength compared to the commercial adhesive, reaching an average stress at break of 7.66 and 0.113 MPa for the wood and carbon steel substrates, respectively. In conclusion, the bioadhesive can be used for the production of composites.

ABSTRACT Fused Filament Fabrication (FFF) is an Additive Manufacturing process popularized in the last decade due to its easiness of use and lower costs. However, despite its increasing popularity, the process itself has several gaps in knowledge, hindering further uses on more advanced objects. Also, the freedom of design allows significant variances in the printed parts, many influencing production and mechanical properties. This work studies the influences of the infill patterns in the mechanical response of printed parts. Using poly (lactic acid) (PLA), a widely used polymer in FFF process, the mechanical responses of parts printed with different infill patterns were analyzed. Rectilinear, Honeycomb, Triangle and Grid patterns were tested on impact resistance and tensile strength. Additionally, samples masses were measured and compared to the mechanical response. Results shown significant differences in the on tested properties. Tensile strength varied from 2.4 to 1.1 MPa, and impact resistance from 3.8 to 1.5 kJ/m2 Also, measured mass was found to be significantly higher on the Honeycomb pattern. Considering mechanical response from both tensile and impact tests along with printed mass, Rectilinear pattern can be considered the most advantageous from the economic point of view.

Abstract This work investigated the effect of thermal treatment in an autoclave on the chemical, physical, and morphological properties of lignocellulosic fibers from açaí (Euterpe oleracea Mart), and the behavior of this treated fiber in polypropylene (PP) matrix composites with polypropylene-graft-maleic anhydride (PPgMA) as the coupling agent. The treated and untreated fibers were characterized by chemical composition, x-ray diffraction, FTIR spectroscopy, and thermogravimetry, scanning electron microscopy and tensile tests were carried out for the composites. The results showed that the thermal treatment modified the hemicellulose and lignin content and increased the fiber surface roughness, without compromising the thermal stability. The composite prepared with thermally treated fibers and PPgMA exhibited an increase in tensile strength but a reduction in tensile modulus. In conclusion, the thermal treatment of vegetable fiber is a promising technique for improving the performance of composites.

ABSTRACT The growth of oil exploration and transport in marine environments brings concern over potential environmental disasters caused by oil spills. Thus, various materials are being developed and studied in order to minimize environmental impacts caused by these oil spills. Among these materials, the use of sorbents has appeared as a great potential technique for the treatment of effluents, by separating and collecting oil in the aqueous medium. This work describes the development of a sorbent system based on acetylated microfibrillated cellulose. Initially, cellulose fibers were modified by an acetylation reaction and thereafter, by a mechanical process using a wheel mill grinding. To produce the sorbent system, fibers were coated by three different types of envelopes to prevent leakage during the sorption experiment. Main results indicate a higher oil sorption by sorbents with higher oil viscosity and higher grammage of the envelope. Acetylated microfibrillated cellulose showed low water adsorption and high selectivity to oil and greater oil sorption values than commercially sorbent currently used, based on polypropylene fibers.

The production of a material with rigid, multifunctional three-dimensional porous structure at a low cost is still challenging to date. In this work, a light and rigid carbon foam was prepared using rice husk as the basic element through a simple fermentation process followed by carbonization. For the fermentation process, the amount of biological yeast (7.5 g for the carbon foam CA-1P and 5 g for the carbon foam CA-2P) was used to evaluate its influence on the morphology of the foams. In order to prove that the heat treatment made in the foam alters the hydrophilic character of the rice husk foam, a chemical treatment with steam deposition was carried out. The foams were characterized by the following analyzes: apparent density, micrograph, thermogravimetry, contact angle, water sorption capacity and thermal conductivity. Visually, the CA-1P foams presented a structure with larger pores due to the greater amount of yeast used in its formulation. The heat treatment of rice potato foams proved to be as efficient as the chemical treatment for water contact angle above 90º, proving the ability of the foams to repel water/moisture. The thermal conductivity of the foams (0.029 and 0.026 W m-1 K-1 for CA-1P and CA-2P, respectively) was close to the conductivity of polyurethane foams (0.032 W m-1 K-1). Thus, the method used in the production of the carbon foams produced from the rice husk proved to be effective. In addition, the foams produced have the potential to be used for thermal insulation.

Abstract Ballistic armor has been manufactured primarily based on polyaramide (Kevlar and Twaron) or Dyneema but the lifespan warranty in Brazil is only 5 years and after this time period they are incinerated or comminuted and ground up. This study aims to evaluate the changes on the physical, mechanical and morphological properties of polyaramide fibers of ballistic armor after natural aging. These samples with different fabrication (2005 and 2010) and usage time were exposed to natural weathering in the city of Porto Alegre, southern Brazil, during the period of one year. Morphology fiber results surfaced after ageing, it showed fiber swelling, stress cracking and defibrillation, and the results of the mechanical tensile testing of the polyaramide fibers showed a pronounced decrease (80%) in tensile strength. It can be concluded that the weight, the dtex of the fiber and the kind of fabric can influence the degradation degree under natural exposure.

RESUMO A indústria de calçados emprega em seus produtos diversas matérias primas derivadas do setor de plásticos. Um dos mais utilizados é o laminado sintético de PVC, utilizado na construção de cabedais devido à grande versatilidade de cores, estampas e espessuras. O laminado é composto de PVC e de fibra têxtil, normalmente na proporção mássica de 60/40. O corte das peças gera uma grande quantidade de aparas que normalmente são descartadas ou depositadas em aterros sanitários ou ARIPs (Aterros de Resíduos industriais Perigosos). O presente trabalho avalia a viabilidade de incorporação destes resíduos em forma de pó em matriz de PVC virgem para uso em solados nas proporções de 0, 5, 15, 25, 35 pcr (partes por cento de resina), bem como seu desempenho mecânico. Foram avaliadas propriedades físico-mecânicas com tração, dureza shore A e colagem, microscopia eletrônica de varredura (MEV) e espectroscopia no infravermelho (FTIR). Os resultados dos ensaios de dureza e tração demonstraram um decréscimo no desempenho na medida em que a concentração de resíduo no compósito aumentou. A força de colagem também apresentou queda na resistência final obtida pelo efeito pull out, confirmado pelas micrografias da superfície de fratura. Pode-se dizer que as misturas com resíduos de laminados em pó apresentam características aceitáveis, segundo as normas indicadas e os padrões especificados para a utilização como material para solado. Além disso, a incorporação deste resíduo diminui a quantidade de material descartado reduzindo o impacto ambiental.

ABSTRACT The footwear industry uses in its products various raw materials derived from the plastics sector. One of the most used is the synthetic PVC laminate, used in the construction of leather because of the great versatility of colors, prints and thicknesses. The laminate is composed of PVC and textile fiber, usually in the mass ratio of 60/40. Cutting of parts generates a large amount of shavings that are normally discarded or deposited in landfills or ARIPs (Hazardous Industrial Waste Landfills). The present work evaluates the feasibility of incorporating these residues in the form of powder in virgin PVC matrix for use in soils in proportions of 0, 5, 15, 25, 35 pcr (parts per cent of resin), as well as their mechanical performance. Physical-mechanical properties with traction, shore A hardness and bonding, scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) were evaluated. The results of the hardness and tensile tests showed a decrease in performance as the concentration of residue in the composite increased. The bond strength also showed a decrease in the final resistance obtained by the pull out effect, confirmed by fracture surface micrographs. Mixtures with powdered laminate residues may be said to have acceptable characteristics, in accordance with the standards indicated and the standards specified for use as flooring material. In addition, the incorporation of this residue reduces the amount of material discarded reducing the environmental impact.

ABSTRACT The fouling formation in the EVA production leads to an increase in the residence time of the material. This result is a favorable condition to generation of the crosslinks during the polymerization. The crosslinking allows raising the molar mass of the polymer, which after the polymerization reaction are characterized as gels, thus generating problems in the product quality during production due to contamination of the resin. This paper describes the fouling process in the reactor, the defouling mechanism, the crosslinking, the scission of chain and presents a study on the influence of the reaction temperature in relation to the formation of gels by quantitative analysis by Optical Controller System -OCS. The average temperature rise of the reaction at 10 ºC, helped to reduce the generation of gels due to the viscosity reduction over the reactor, which reduces the polymer residence time in the walls of the tube and consequently the formation of fouling.