Proton exchange membrane water electrolysis (PEMWE) performs the electrolysis of water to produce hydrogen, a source of clean and renewable energy. The most used commercial electrolyte in PEMWE is the Nafion membrane, a material that is expensive and difficult to recycle. The partial replacement of Nafion with cellulose nanocrystals (CNCs) can produce composite membranes can increased electrical, mechanical and biodegradability properties. In this sense, the objective of this work is to study the elaboration of nanocomposites (Nafion-CNC) aiming at developing high-performance electrolytes for application in PEMWE. The effects of adding CNCs to Nafion were evaluated. Nafion membranes were produced with two types of CNCs, one obtained by enzymatic hydrolysis and the other by acid hydrolysis (commercial). The addition of both CNCs has similar effects on Nafion's properties. For samples with both commercial and enzymatic CNC, an increase in the modulus of elasticity (10% and 40% respectively) and maximum stress (10% and 13% respectively) was observed. The two nanocomposites showedlower initial thermal degradation temperatures, however, they still showed sufficient stability (Tonset gt; 170°C) for application in PEMWE (standard operating temperature lt;100°C). Furthermore, there was a significant increase in the humidification capacity and increase in conductivity. Composite membranes were tested in PEMWE and their usability was proven.

La electrólisis del agua con membrana de intercambio de protones (PEMWE) realiza la electrólisis del agua para producir hidrógeno, una fuente de energía limpia y renovable. El electrolito comercial más utilizado en PEMWE es la membrana Nafion, un material caro y difícil de reciclar. El reemplazo parcial de Nafion con nanocristales de celulosa (CNC) puede producir membranas compuestas que pueden aumentar las propiedades eléctricas, mecánicas y de biodegradabilidad. En este sentido, el objetivo de este trabajo es estudiar la elaboración de nanocompositos (Nafion-CNC) con el objetivo de desarrollar electrolitos de alto rendimiento para su aplicación en PEMWE. Se evaluaron los efectos de agregar CNC a Nafion. Las membranas de Nafion se produjeron con dos tipos de CNC, uno obtenido por hidrólisis enzimática y el otro por hidrólisis ácida (comercial). La adición de ambos CNC tiene efectos similares en las propiedades de Nafion. Para muestras con CNC tanto comerciales como enzimáticas, se observó un aumento en el módulo de elasticidad (10% y 40% respectivamente) y tensión máxima (10% y 13% respectivamente). Los dos nanocompuestos mostraron temperaturas iniciales de degradación térmica más bajas, sin embargo, aún mostraron suficiente estabilidad (Tonset gt; 170 °C) para su aplicación en PEMWE (temperatura de operación estándar lt;100 °C). Además, hubo un aumento significativo en la capacidad de humidificación y un aumento en la conductividad. Las membranas compuestas se probaron en PEMWE y se comprobó su usabilidad.

A eletrólise da água com membrana de troca de prótons (PEMWE) realiza a eletrólise da água para produzir hidrogênio, uma fonte de energia limpa e renovável. O eletrólito comercial mais utilizado no PEMWE é a membrana de Nafion, um material caro e de difícil reciclagem. A substituição parcial do Nafion por nanocristais de celulose (CNCs) pode produzir membranas compostas com propriedades elétricas, mecânicas e de biodegradabilidade aumentadas. Nesse sentido, o objetivo deste trabalho é estudar a elaboração de nanocompósitos (Nafion-CNC) visando o desenvolvimento de eletrólitos de alto desempenho para aplicação em PEMWE. Os efeitos da adição de CNCs ao Nafion foram avaliados. As membranas de nafion foram produzidas com dois tipos de CNCs, um obtido por hidrólise enzimática e outro por hidrólise ácida (comercial). A adição de ambos os CNCs tem efeitos semelhantes nas propriedades do Nafion. Para amostras com CNC comercial e enzimática, observou-se um aumento no módulo de elasticidade (10% e 40% respectivamente) e tensão máxima (10% e 13% respectivamente). Os dois nanocompósitos apresentaram menores temperaturas iniciais de degradação térmica, porém, ainda apresentaram estabilidade suficiente (Tonset gt; 170°C) para aplicação em PEMWE (temperatura padrão de operação lt;100°C). Além disso, houve um aumento significativo na capacidade de umidificação e aumento na condutividade. As membranas compostas foram testadas em PEMWE e sua usabilidade foi comprovada.

Abstract Sulfiting agents are added to crustaceans products to prolong their shelf life. However, depending on the concentration, these agents can be toxic to consumers due to the presence of SO2. In this context, a colorimetric indicator label based on starch and iodine was developed to detect SO2 in shrimp, showing whether the product is safe or not for consumers. The incorporation of iodine into the starch matrix resulted in labels with a smooth and homogeneous surface, and reduced water solubility from 9.26% to around 0.12%. In both in vitro and shrimp paste test, a visual detection response was observed in the label containing 0.02% of iodine when evaluated in the presence of 100 to 160 ppm of SO2, with ΔE* values greater than 5 (can be identifiable by the human eye). Therefore, the elaborated label showed potential as an economical and simple method to detect SO2 concentration in shrimp-based foods.

ABSTRACT The aim of this research was to investigate sugarcane bagasse (SCB) particleboards, using two kinds of particles, from pith and fibers, reinforced with cellulose nanocrystals (NCC). The NCCs were dispersed in the adhesive urea formaldehyde (UF) using a sonificator in two proportions (0 and 1%). The NCCs and UF were applied in the SCB particles using a rotary blender. The particleboards were produced in three layers using two kinds of particles: pith and fibers. After dispersion of the adhesive, the mixture was compressed to produce the particleboards, which were characterized by physical, mechanical and thermal properties. The anatomical and chemical features relating to pith and fiber were very similar. The particleboards made with and without NCCs did not differ statistically for most properties: modulus of elasticity (MOE), modulus of rupture (MOR), water absorption (WA) thermal conductivity (TC), and the volume heat capacity (VHC). Particleboards made only with fibers and without NCCs showed higher internal bond (IB). In the other hand particleboards made only with fibers in the face and pith in the core (without NCCs) showed lower thickness swelling after 24 hours (TS24h). Probably, the NCCs did not improve the particleboards performance, because less links were available for SCB to interact with the adhesive. For the others properties the particleboards made with pith and fibers did not showed statistical difference (MOE, MOR, TC, WA, TC and VHC), demonstrating that separation of pith and fiber are not significant and does not affect the final properties of particleboards.

ABSTRACT The objective of this study was to evaluate the polyester-based fiber composites reinfor ced with filaments/fibers of mauve treated with NaOH and maleic anhydride. The che mical treatment of the mauve filament/fibers (3 cm of length) was carried out, first with NaOH, followed by maleic anhydride. The resin used was ortho unsaturated polyester with addition of catalyst peroxide methyl ethyl ketone. The composites were prepared with 15% filaments (w/w) and tested for water absorption, three-point bending, tensile and impact strength. Fiberglass composites were produced using the same methodology for comparison purpose. The results demonstrate the potential use of mauve filaments. For some properties, the mauve composites showed better mechanical properties than fiberglass composites (three-point bending and tensile). The treatment of the filaments had varied effect and did not improve the mechanical properties. However, for the water absorption was observed a reduction of 35% in composites with treated mauve filaments.

Thermoplastic starch properties depends of plastification process. The aim of this study was to analyze the effect of concentration of glycerol and water on plastification, glass transition temperature (Tg) and tensile properties of thermoplastic waxy starch (TPWS). Formulations were extruded in the following concentrations of starch/glycerol/water: 70/30/0 (TPWS 0%); 70/25/5 (TPWS 5%); 70/20/10 (TPWS 10%) weight percentage. Crystalline peaks in WAXS diagrams and native grains present in SEM micrographs showed that the TPWS 0% and 5% were not sufficient to promote total plastification of the waxy starch, and TPWS 10% showed the higher starch plastification. Tg measurements by DMTA were 30 ºC to TPWS 0%, 23 ºC to TPWS 5% and 40 ºC to TPWS 10%. These results showed that glycerol and water had effect plasticizer in TPWS 5% and antiplasticizer in TPWS 10%. Mechanical tensile results showed that higher tensile strength was observed in the systems with more effective starch plastification.

The aim of this study was to evaluate the potential use of sisal and coir fibers in combination with Eucalyptus particles for the production of particleboard. The particleboards were produced in three layers. The first and third layers (face) were made with small Eucalyptus particles. The second layer (core) was made with big Eucalyptus particles in combination with coir or sisal fibers. The particleboards were prepared with the substitution on Eucalyptus wood for sisal and coir fibers in the particleboards core, in doses of 0, 10, and 20%, relative to the total mass of particles. The particleboards were characterized by mechanical, physical and thermal properties. The results were not satisfactory for particleboards with sisal. However, for coir particleboards the physical-mechanical properties were very similar to those particleboards produced only with Eucalyptus. This work demonstrates the potential use of the coir that is commonly disposed in landfills on the Brazilian beaches.

Abstract This paper reports on a study of highly filled composites of polypropylene (PP) and 75% by weight sugarcane bagasse fiber with and without alkali treatment and with and without coupling agent (SEBS-g-MA). Composites were prepared using a Rheomix600 mixer connected to a HAAKE torque rheometer. The thermal and mechanical behavior of these composites were investigated by thermogravimetry (TGA), differential Scanning Calorimetry (DSC), flexural tests, impact tests and scanning electron microscopy. Scanning electron microscopy (SEM) images taken from sugarcane bagasse fibers showed enhancements in the fiber's surface topography after the surface treatment process. The FTIR, TGA and SEM results for the fibers showed that the alkali treatment modified the fiber surface as well as the chemical composition. The impact test results showed a good potential of SEBS-g-MA as coupling agent and impact modifier in highly filled composites, increasing by more than 100% the impact strength of the composite as compared to those without the coupling agent. Scanning electron microscopy showed that addition of coupling agent improved the interfacial adhesion between the fibers and polypropylene.

The objective of the present study was to evaluate lignocellulosic particles from sub-products of the coffee industry (coffee parchment - CP and husk - CH) into polyhydroxybutyrate (PHB) as a promising reinforcing filler in the biocomposites. The effects of type (CP or CH) and content (neat, 10% and 20%) of coffee wastes on the thermal, mechanical, microstructural and physical properties of the ensuing composites were evaluated. Thermal stability of the composites was improved by the coffee residues at different contents, while degree of crystallinity was decreased with the inclusion of CP. The addition of 10% of CP has not influenced significantly the tensile strength (TS) and Izod strength (IS), in relation to the neat PHB. Tensile strength (TS), MOE and Izod strength (IS) of the composites have increased significantly with the inclusion of 20% of CP. The increase in the content of coffee waste particles increased the water absorption of the composites.

The thermal behavior of a mixture of recycled polyolefins (PE/PP mix), variously colored recycled polyolefins, recycled polyolefin blends and recycled polyolefin/PET blends was analyzed by thermogravimetry. Atmospheres of nitrogen and synthetic air were used to compare the effects of inert and oxidative medium. Four characteristic temperatures, T1, T2, T3 and T4, related to oxidative processes and atmospheric conditions, were defined. Relationships between T1, T2, T3 and T4 and comparing pigmented and transparent material allow assessing the effect of different pigments on volatilization, oxidation and onset temperatures of decomposition processes. These analyses provide preliminary parameters for selecting acceptable processing temperature conditions of recycled household and engineering plastics, and provide a few criteria to select colored recycled polyolefins.