Ionic polymer-metal composites (IPMC) are typical electromechanical transducing materials suitable for use as soft actuators, bioinspired artificial muscles and sensors. However, IPMC produced with platinum films has the great disadvantage of the large number of cracks and wrinkles, which reduce the performance of the electrode. Polyaniline (PANI) is a promising conductive polymer that can address this issue, especially when it is electropolymerized on the platinum surface. An IPMC/PANI actuator was developed by potentiostatic electropolymerization of PANI at 0.9 V in 0.1 M and 0.3 M aniline solution. The characterization revealed that PANI is preferentially electropolymerized in the platinum film cracks and improve the electronic conduction mechanisms, which is not reported so far. The maximum tip displacement of the IPMC/PANI under 5 V was 8.3 mm, while for the IPMC was equal 5.2 mm. These results provide a simple and effective method to repair IPMCs and enhance their electromechanical performances.

This research was aimed to obtain biodegradable polymeric films with antifungal action against Aspergillus niger, through the addition of copper oxide nanoparticles (CuO-NPs) in the commercial polymer (Ecoflex®) and to evaluate its mechanical, morphological, biodegradation, and copper release properties. The microbiological results showed that the films with 4 wt% CuO-NPs inhibited 97.57% the growth of the fungus growth of 1×105 spores·mL-1 compared to the control. The morphological characterization revealed that the CuO-NPs presented irregular form with particles size of 50 to 400 nm and the XRD showed characteristic peaks of copper oxide. The addition of CuO-NPs to Ecoflex® provided increased maximum and rupture tension, strain, and elasticity modulus the obtained films with 1 wt% CuO-NPs and did not alter the biodegradability of the films. It can be said that, through the addition of CuO-NPs to Ecoflex®, it was possible to add antifungal activity for Aspergillus niger without compromising its biodegradability, meeting the safety standards established by legislation regarding the release of copper.

Composites based on green high-density polyethylene (G-HDPE) and hydroxyapatite (HA) compatibilized with maleic anhydride grafted high-density polyethylene (HDPE-g-MAH) were developed in this work. The main objective was to evaluate the effects of HA and HDPE-g-MAH contents on the mechanical and thermal properties and hydrolytic degradation of composites through design of experiments and statistical analysis, as well as to evaluate the hemolytic stability. Hydroxyapatite acts as a reinforcing agent for the G-HDPE matrix while the HDPE-g-MAH acts as a compatibilizing agent, improving the dispersion of the HA particles in the polymer matrix and thus increasing the mechanical properties. The crystallization temperature and the degree of crystallinity of the polymer matrix were increased with the addition of HA, suggesting the filler acts as a heterogeneous nucleating agent. Hemolysis tests performed on a composite sample with best mechanical performance did not indicate significant hydrolytic degradation, which suggests this composite is a promising material to be used in bone tissue engineering, for application in implants and bone grafts. highdensity high density GHDPE G HDPE (G-HDPE (HA HDPEgMAH g MAH (HDPE-g-MAH work analysis stability engineering grafts

The Montmorillonite-Erucamide nanocomposite (MMT-EU) can be used to reduce and to control the values of coefficient of friction of low-density polyethylene films (LDPE), widely used by the food industry. In this work, the effect of the addition of 5 wt% and 10 wt% of MMT-EU on the mechanical properties of LLDPE films involving the weld region was investigated. The MMT-EU concentration range was defined considering its possible technological application as an additive to stabilize the friction coefficient of polymeric films. The result shows a significant improvement in the values of stiffness, strength and ductility of polymeric films. In addition, it did not change the coefficient of friction, but the brightness of the LLDPE films decreased and the opacity increased, due to the increase in the crystallinity degree of the LLDPE polymer promoted by MMT-EU, not being a problem for the application of these films.

resumo: O cimento Portland continua sendo o principal material de escolha na construção civil, devido às suas propriedades térmicas, mecânicas e de durabilidade. No entanto, há uma crescente preocupação com a grande quantidade de energia consumida e a poluição ambiental gerada durante sua produção. Dessa forma, a presente pesquisa buscou avaliar o potencial do material residual fino produzido pela britagem de rochas basálticas através da ativação alcalina, para formar uma matriz cimentícia suplementar. O pó do basalto com tamanho de partículas menor que 53μm foi preparado e ativado com solução de hidróxido de sódio, tendo como coadjuvante a solução silicato de sódio. O material também teve o processo de cura realizado em 5 níveis de temperatura, 74,8, 85, 100, 115, 125,2°C conforme o delineamento experimental. Depois de curado o material teve a resistência à compressão avaliada, atingindo valor médio de 10,21 MPa para a mistura H5S15T125. A análise da microestrutura foi realizada através da microtomografia de raios X, apresentando a reconstrução dos poros e fissuras presentes internamente, concluindo que temperaturas de cura mais altas formaram matrizes mais porosas, embora com mais resistência. A partir dos dados coletados foi realizada a análise estatística do planejamento apresentando que hidróxido de sódio e a temperatura apresentam efeito estatisticamente significativo na variável resposta resistência à compressão. Portanto, é possível através da álcali-ativação do pó de basalto produzir um material cimentício de resistência moderada, dando finalidade ao resíduo e diminuído a emissão de partículas nocivas à atmosfera.

resumo: Portland cement remains the main material of choice in construction due to its thermal, mechanical and durability properties. However, there is growing concern about the large amount of energy consumed and the environmental pollution generated during its production. The objective of this study, therefore, was to evaluate the potential of the fine residual material produced by crushing basalt rocks to form a supplementary cementitious matrix through alkaline activation. Basalt powder with a particle size of less than 53µm was prepared and activated with a sodium hydroxide solution, with a sodium silicate solution as an adjuvant. The curing process of the material was also carried out at 5 temperature levels, 75, 85, 100, 115, 125°C, according to the experimental design. The paste was dry curing at a standard digital laboratory oven for 24 hours. After curing, the compressive strength of the material was evaluated, reaching a mean value of 10.21 MPa for the H5S15T125 mixture at 28 days. The microstructure analysis was performed by X-ray microtomography, presenting the reconstruction of the internal pores and cracks, leading to the conclusion that higher curing temperatures formed more porous matrices, although with more strength. Based on the collected data, the statistical analysis of the design was performed showing that sodium hydroxide and temperature have a statistically significant effect on the response variable compressive strength. As such, the alkali-activation of basalt powder can potentially produce a cementitious material of moderate strength, giving purpose to the residue and reducing the emission of harmful particles into the atmosphere.

ABSTRACT In this work, magnesium oxide nanoparticles were synthesized by the sol-gel route and their ecotoxicity was tested in worms of the Eisenia andrei species. Magnesium oxide nanoparticles were characterized by XRD, surface area via BET, TEM and SEM-FEG/EDS. The lethality test with Eisenia andrei earthworm species followed the recommendations of ISO 11268-1 (ISO, 2012) in a completely randomized design with six replicates for each concentration tested (1.06, 2.12, 4.24, 8.48 and 16.96 μg of NPs-MgO/kg of soil), plus the control. The concentrations were mixed to the tropical natural soils, Entisol Typic Quartzipsamments and Oxisol, with no agricultural use history. The morphological and structural analyses of the nanoparticles indicated the formation of magnesium oxide with cubic structure, constituting agglomerates of nanostructures of the order of 20 to 50 nm. The results of toxicity were submitted to analysis of variance (ANOVA One-way), followed by the Dunnett test (p <0.05). Based on standardized toxicological tests it was found that NPs-MgO, at the concentrations tested, did not affect the survival of Eisenia andrei species in the natural soils studied.

RESUMO O estudo da atividade metanogênica específica (AME) constitui uma importante ferramenta para o controle operacional de reatores anaeróbios, pois apresenta parâmetros de monitoramento da eficiência e estabilidade de um reator biológico. Nesse sentido, o presente trabalho visou determinar a AME de lodos provenientes de reatores anaeróbios de fluxo ascendente (UASB - upflow anaerobic slugde blanket) de duas indústrias cervejeiras (lodos A e B), uma de processamento de grãos (lodo C), uma leiteira (lodo D) e uma de processamento de couro (lodo E). Os ensaios foram conduzidos em batelada, em ambiente aclimatado a 35°C, utilizando um equipamento para monitorar a geração de biogás em função do tempo de digestão. Também foi realizada a qualificação do gás metano presente no biogás gerado pelos diferentes lodos. O maior valor de AME obtido e a maior porcentagem do gás metano produzido, para uma concentração de biomassa de 5,0 gSTV.L-1 e 4,0 gDQO.L-1 de glicose, foram para o lodo B: 0,36 gDQO-CH4.gSTV-1.d-1 e 58,9%, respectivamente.

ABSTRACT The study of Specific Methanogenic Activity (SMA) is an important tool for operational control of anaerobic reactors, as it presents parameters to monitor the efficiency and stability of a biological reactor. For this reason, the present article aimed to determine the SMA of sludges from UASB reactors, of two different brewing industries (sludges A and B), a grain processing industry (sludge C), a dairy industry (sludge D), and a leather processing industry (sludge E). Assays were performed in batch, at an acclimatized environment (35°C), using a device equipment to monitor the generation of biogas due to digestion time. Also, the quantity of methane gas was measured in the biogas generated by the different sludges. The best SMA value obtained and the greater percentage of methane gas generated, with a biomass concentration of 5.0 gSTV.L-1, and a glucose concentration of 4.0 gCOD.L-1, were for sludge B, with 0.36 gCOD-CH4.gSTV-1.d-1 and 58.9%, respectively.

Tetracycline is used to treat various diseases in animals and humans, so its high use causes this substance to be frequently found in effluents and in potable water reservoirs, causing serious problems for human health and the environment. Many processes are applied and evaluated in an attempt to removal tetracycline found in environment, such as adsorption. The application of iron-carbon nanoparticles with core-shell structure (Fe3O4@C) as adsorbent, can be an alternative to removal of these contaminants. In the present study Fe3O4@C nanoparticles were synthesized and used to adsorb tetracycline in aqueous solutions. The core-shell characterization was performed using X-ray diffraction techniques, infrared spectroscopy, surface area, chemical analysis and morphology, and adsorption capacity through isotherms. The results indicated that Fe3O4@C nanoparticles presented good tetracycline removal capability, 73.3%, when applied an initial concentration of antibiotic of the 30 mg L-1 and 0.5 g of adsorbent.

ABSTRACT: In recent years, various studies and development using nanoparticles (NPs) have been carried out in the most diverse areas of knowledge. Although nanomaterials are widely employed by many sectors and some may have a fertilizing potential, little is known about their effects on the environment. This study aimed to evaluate the effect of applying, in tropical natural soil, different contents of nanoparticles of zinc oxide (NPs-ZnO) and non-nano zinc oxide (ZnO) on soil pH and on the survival and reproduction rates of earthworms ( Eisenia andrei ) and springtails ( Folsomia candida ) through standardized ecotoxicological tests. The tests used a tropical soil representative of Brazil, classified as Entisol ( Neossolo Quartzarênico órtico típico ) with no history of agricultural use, collected in the 0.00-0.20 m layer, previously sieved (2-mm mesh) and defaunated. The experimental design was completely randomized, and treatments consisted of two forms of zinc (Zn), NPs-ZnO and ZnO, at the following doses: 0, 50, 100, 200, 400, 800, 2,000, and 4,000 mg kg−1. Standardized ecotoxicological tests showed no toxicity of NPs-ZnO in terms of lethality of E. andrei and F. candida . In E. andrei reproduction tests, NPs-ZnO were toxic at doses higher than 400 mg kg−1 (EC50 of 1,021 mg kg−1). Tests with F. candida demonstrated that its reproduction rate was significantly affected by NPs-ZnO at a rate of 4,000 mg kg−1 (EC50 of 3,636 mg kg−1). When used in Entisol, the NPs-ZnO inhibit the reproduction of earthworms and springtails; earthworms are more sensitive to such an effect, it being demonstrate at lower contents than those found for springtails.

Zinc is an important chemical element in many metabolic mechanisms at low concentrations, but can be toxic when administrated in doses higher than 500 µg·g-1 or 3 mg·L-1. This metal has been detected in many aquatic environments due to several industry activities and swine manure effluents. Thus, the contaminant removal of water and wastewater has been a major challenge. Many processes are applied and evaluated in an attempt to removal zinc found in environment, such as adsorption. In the present study Fe3O4@C core-shell nanoparticles were synthesized and used to adsorb ionic zinc species in aqueous solutions. The core-shell nanoparticles exhibited excellent zinc removal capacity, with a maximum efficiency equal 65% where applied in an aqueous solution containing 10 mg·l-1 of this ionic metal.

Civil construction is one segment responsible for major environmental and social impacts. Among its raw materials, Portland cement, which is produced by the burning and subsequent grinding of a composition of clays and limestones. This manufacturing process causes great environmental damage, both by the exploitation of deposits and by the process of clinkering (burning of raw materials), which emits a significant amount of CO2 in the atmosphere. Therefore, there is a need for research on materials that reduce these impacts on the environment and that can be used by civil construction to the partial replacement of cement. Thus, this research had as objective to produce settlement mortar through the partial replacement of the Portland cement by filler powder, in different proportions and to study its mechanical properties. The results show that the partial replacement of the cement by the residue has acceptable behavior in the mortar.

RESUMO A indústria de polímeros tem passado por muitos avanços na última década, dentre eles, podem-se citar as inovações em processamento e no uso de aditivos, o que permite que eles sejam utilizados em diversas aplicações, especialmente quando expostos ao ambiente externo. Porém, para algumas aplicações específicas, o polímero precisa ser submetido a tratamentos de superfície, com o objetivo de aumentar a rugosidade superficial. Por este motivo, muito ainda precisa ser estudado no que diz respeito aos aditivos utilizados no processamento de polímeros quando ele é submetido a processos de transformação, podendo-se citar o tratamento corona. Desta forma, este trabalho tem o objetivo de avaliar as modificações estruturais causadas em aditivos estabilizantes presentes em filmes poliméricos quando são submetidos a tratamento corona. Três diferentes absorvedores de UV foram avaliados: benzofenona, benzotriazol e triazina. Os filmes foram processados por spin coating e submetidos à radiação ultravioleta, com o objetivo de simular a exposição externa do polímero e a tratamento corona. Analisando os resultados obtidos, pode-se perceber que o único aditivo que resistiu às condições de tratamento foi o benzotriazol, mantendo a absorção da radiação ultravioleta, mesmo após o tratamento corona e protegendo o polímero da degradação UV. Os outros aditivos sofreram processos degradativos, causadas pelo tratamento corona, e a absorção da radiação ultravioleta, apresentada previamente, deixa de existir.

ABSTRACT The polymer industry has undergone many advances in the last decade, among them, innovations in the processing and in the use of additives, which enable the use of polymers in several areas, especially, when exposed to external environment. However, for some specific applications, the polymer must be submitted to surface treatments in order to increase its superficial roughness. Then, much remains to be studied regarding the behavior of these additives when exposed to transformation processes in which the polymers are normally subjected, as for example, the corona treatment. Thus, this study aims to evaluate the structural modifications in stabilizing additives present in polymeric films, when subjected to corona treatment. Three different UV absorbers additives were evaluated: benzophenone, benzotriazole and triazine. The films were processed by spin coating and subjected to ultraviolet radiation, in order to simulate the external exposition of the polymer, and corona treatment. Analyzing the results obtained, it was realized that the only additive that resisted to thetreatment conditions was benzotriazole, maintaining the absorption of ultraviolet radiation even after corona treatment and protecting the polymer from UV degradation. The other additives suffered degradation processes, caused by corona treatment, and the absorption of ultraviolet radiation presented earlier, ceases to exist.

ABSTRACT This work describes the second of a series of studies of the effects of injection molding conditions on the mechanical and thermal properties of Polyamide 6/Glass Fiber/Montmorillonite (PA6/GF/MMT) composites and was motivated by the lack of information about how the processing variables influence on the properties of three-phase composites containing fiber glass. By this time, the effects of the injection molding temperature associated with the fiber glass percentage on the mechanical and thermal properties of the composite are investigated. Some samples were processed, following a statistical experimental factorial planning, varying the mold temperature and the fiber glass percentage and maintaining 5 wt % of the MMT. The samples were submitted to tensile and flexural tests, XRD, SEM and DSC. The studies showed that an increase in the mold temperature and the fiber percentage improves the maximum tensile and flexural stresses. The increased mold temperature slows the cooling rate, which, over time, decreases the degree of crystallinity. However, there is an increase in the intercalation of the polymeric chains and the nanoclay lamellae, and the structure forms with fewer defects.

ABSTRACT The electroactive polymers have been the subject of many studies in the last decade, mainly because its unique properties. They are used in composite structures, which allow its application in many fields, as for example, sensors and artificial muscles. The electrical properties of these composites are influenced by the doping state of the electroactive polymer, which is controlled during its synthesis process. Therefore, this work aimed to evaluate how the synthesis parameters influence the electrical conductivity of the composite PANI/PVDF. The synthesis parameters evaluated were the concentrations of monomer, initiator and dopant, and the synthesis time. PANI was obtained by chemical polymerization in a solution containing PVDF and the solvent DMF. To evaluate possible changes in the chemical structure of the composite, the samples were submitted to FT-IR and XRD analysis. It was possible to conclude that the parameters relative to the production of PANI directly influence in the electrical conductivity of the composite. So, the sample produced with major quantities of monomer, initiator and dopant were statistically significant to increase the electrical property of the composite.

Resumo Hoje em dia é crescente a quantidade de estudos envolvendo a utilização de cargas ou aditivos nos materiais poliméricos, em especial no poliestireno, a fim de atuar como retardante de chama. Partindo desse princípio, este trabalho compara o comportamento térmico dos compósitos de poliestireno/hidróxido duplo lamelar magnésio-alumínio (PS-HDL [Mg-Al]) em relação ao poliestireno puro. Os compostos foram preparados com HDL, quimicamente modificado com dodecil sulfato de sódio (SDS-Na) ou com dodecilbenzeno sulfonato de sódio (DBS-Na). A síntese desses aditivos (HDL-SDS e HDL-DBS) foi feita pelo método de coprecipitação e inseridos no PS via solubilização em clorofórmio. Os compostos foram caracterizados por difratometria de raios-X e espectroscopia de infravermelho por transformada de Fourier, onde o primeiro comprovou a intercalação do DBS/SDS com o HDL e o segundo confirmou a presença dos grupos característicos no HDL. Através da análise termogravimétrica, avaliaram-se as propriedades térmicas do compósito. Os resultados mostraram que o PS-HDL modificado comporta-se melhor que o PS puro, pois apresenta maior estabilidade térmica. Comparando-os em uma perda de massa de 50%, o PS-HDL-SDS apresentou resultado superior ao PS puro, com um ganho de aproximadamente 44 ºC na temperatura de decomposição térmica.

Abstract Nowadays there is an increasing number of studies involving the use of fillers or additives for polymeric materials, in particular polystyrene, as flame retardants. Starting from this principle, this paper compares the thermal performance of composites of polystyrene/double layered magnesium-aluminium hydroxide (PS-LDH [Mg-Al]) compared to pure polystyrene. Compounds were prepared with LDH, chemically modified with sodium dodecyl sulphate (SDS-Na) or sodium dodecylbenzene sulfonate (SDB-Na). The synthesis of these additives (SDS-LDH and SDB-LDH) was carried out by the coprecipitation method and inserted via the PS dissolution in chloroform. The compounds were characterized by X-ray diffraction and Fourier transform infrared spectroscopy, where the first method proved the intercalation of the SBD/SDS with LDH and the second confirms the presence of the characteristic groups in LDH. Thermal properties of the composite were evaluated by thermo gravimetric analysis. The results showed that the modified PS-LDH behaves better than pure PS, it has higher thermal stability. Comparing them in a mass loss of 50%, the PS-LDH-SDS showed better results compared to pure PS, with a gain of approximately 44 ºC in the thermal decomposition temperature.