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This study determined the methanotrophic activity in anaerobic sludge from a pilot-scale UASB reactor. Four batch experiments, with three replicates, were performed in 110 mL antibiotic flasks. The results showed that the maximum rate was 115 µmolCH4.d-1 and the methanotrophic activity was 2.3 mmolCH4.gTVS-1.d-1, indicating that the methanotrophic microorganisms play a key role within the UASB reactor since they are part of the sludge microbiota and may consume some of the methane produced inside the reactor. Therefore, these microorganisms may reduce possible methane losses, either atmospheric and/or dissolved in the treated effluent. The microbial community was investigated by molecular tools (PCR-DGGE) and two DNA sequences related to methanotrophic bacteria, Methylocystis sp. (similarity of 93%) and Methylocaldum sp. (similarity of 98%) to 16S rRNA gene sequences, were detected. The methanotrophic activity and the identification of the community of main microorganisms involved allow the reduction of methane into the atmosphere and contribute to the system’s mass balance between production and consumption.

Polystyrene (PS) was blended with shape memory polyurethanes (SMPU). Styrene blocks were grafted onto PU chains during SMPU synthesis to yield a modified SMPU with a higher affinity towards PS. Furthermore, blends containing a compatibilizer, poly (styrene-co-maleic anhydride) (SMA), were also prepared by melt mixing the components. The non-compatibilized blends display phase separated structures with PS rich and SMPU rich phases, which were less evident in blends prepared with either the modified SMPU or SMA compatibilizer. The elastic storage modulus of PS was less affected when blended with SMPU in samples containing modified SMPU with styrene grafts. The impact strength of the blends with higher contents of SMPU modified with styrene blocks (25 and 50 wt.%), after shape recovery, was higher than the impact strength of neat PS. The incorporation of shape memory polymers into a brittle polymer matrix is a potential strategy to improve the toughness by external stimuli.

Calorimetry is the primary technique for measuring the thermal properties of materials. From calorimetric methods, it is possible to perform a correlation between temperature, structure, and the physicochemical properties of the materials. The differential scanning calorimeter (DSC) is one of the most common methods used to determine the thermal properties in polymeric materials. To determine the thermal properties of thermally activated polymeric materials is fundamental for the development of the programming cycle of these materials. This chapter presents a brief discussion about the application of the DSC in determining the thermal transitions of the materials and its correlation with the structure and memory effect.

In this work, the effect of synthesizing shape memory polyurethanes in aqueous dispersions instead of in organic solvents on the structure and properties of the obtained polymers was investigated. Shape memory polyurethanes based on polycaprolactone diol and isophorone diisocyanate were synthesized by two routes: (1) aqueous dispersion (PU/SMWATER) and (2) dissolution in THF (PU/SMTHF). The samples were analyzed by infrared spectroscopy (FTIR), X-ray diffraction (XRD), static light scattering (SLS), atomic force microscopy (AFM), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and mechanical tests. The aqueous dispersion method led to the production of polyurethanes with a higher degree of phase separation and a higher degree of crystallinity. The morphology of the obtained polyurethanes demonstrated that PU/SMWATER displays a structure with better defined phase separated domains. The polyurethanes exhibited similar average molar masses, soft segment glass transitions (Tgs) and mechanical properties. The lower degrees of phase separation and crystallinity of the PU/SMTHF led to lower values for the shape memory properties (shape recovery ratio (Rr)). The observed changes in the structure of the polyurethanes due to the replacement of organic solvent by an aqueous dispersion during their syntheses confirmed the preparation of shape memory polyurethanes with enhanced shape memory properties. POLYM. ENG. SCI., 2016. © 2016 Society of Plastics Engineers

The formation and characterization of poly(itaconic acid)/N-methylol acrylamide/poly(ethylene glycol) (PIA/NMA/PEG) complexes through in situ polymerization of itaconic acid on poly(ethylene glycol) was investigated. FTIR indicated that PEG crystallization was hindered by complex formation. The decrease in the crystallinity of PEG was also observed by DSC and indicated that the mobility of some PEG segments was inhibited by the presence of the polyacid. According to the swelling experiments, complexes proved to be suitable for use as excipient in the preparation of drug delivery systems responsive to pH changing. DMA was used to estimate the crosslink densities and the results were found to be in good agreement with the swelling results. Further, the adhesion strength of the synthesized polymers was used as preliminary evaluation of their potential of mucoadhesion. The results indicated that the adhesion performance is related to the presence of NMA. Drugs which suffer degradation in stomach pH, such as proteins and enzymes are potential candidates to be included in the systems based on PIA/NMA/PEG to pass through the stomach (pH near to 1.2–3.5). Upon reaching the initial portion of the small intestine (pH >5.5), the polymer will swell and release the active substance via diffusion and/or erosion of the matrix.

In this work, the idea of modulating the shape memory properties of polyurethanes by changing their macromolecular architecture through the incorporation of polystyrene-based moieties was investigated. To study these effects, poly(styrene-co-maleic anhydride) (SMA) was incorporated during the synthesis of PU as a potential chain extender. Two sample groups were produced: (i) PU, produced with hydrazine as a chain extender and (ii) PUSMA, produced with the addition of SMA instead of hydrazine. The results suggest that the SMA incorporation in the PUSMA chains occurred by the reaction between NCO groups of the PU and maleic anhydride (MA) of the SMA. The presence of SMA was useful in modulating the structure of PU by reducing the soft segment crystallinity and molar mass. These changes in the structure and macromolecular architecture due to the presence of SMA moieties in PU chains led to pronounced improvements in strength, toughness, and the shape recovery ratio. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44471.

No presente trabalho estudou-se, como alternativa para melhoria das propriedades mecânicas de polímeros frágeis, a incorporação de uma segunda fase polimérica com memória de forma. Para produção das blendas, empregou-se o poliestireno (PS, fase matriz frágil) e o poliuretano com memória de forma (PU/MF, segunda fase). As amostras de PU/MF foram sintetizadas em dispersão aquosa (PU/MFAGUA), dissolução em THF (PU/MFTHF) e com incorporação de poli(estireno-co-anidrido maleico)(PU/MFSMA). As propriedades dos PUs sintetizados apresentaram dependência em relação a fração cristalina proveniente dos domínios macios. O PU/MFAGUA e o PU/MFTHF exibiram comportamento frágil quando estes se encontraram cristalizados e dúcteis após tratamento térmico para controle da cristalinidade. Um estudo do meio de síntese com as amostras de PU/MFAGUA e PU/MFTHF demonstrou que a substituição do THF por água na síntese diminuiu a fração cristalina do polímero. O baixo índice de cristalização no PU/MFSMA provocado pela adição de poli (estireno-co-anidrido maleico) determinou um comportamento dúctil independente de aplicação de tratamento térmico. As blendas foram obtidas através de mistura termomecânica com/sem adição de poli(estireno-co-anidrido maleico). Os materiais produzidos exibiram uma alta separação de fase provocada pela imiscibilidade entre os componentes das blendas. Apresentaram morfologia de fase formada por uma matriz de PS interconectada (componente estrutural) contendo domínios de PU (componente modificador), cuja geometria e dimensões variaram com a concentração. Os ensaios mecânicos apresentaram aumento da resistência ao impacto com tratamento térmico sugerindo ativação do efeito memória de forma. A adição de uma segunda fase com memória de forma se apresentou como uma alternativa para melhoria de propriedades mecânicas de polímeros frágeis. We have studied an alternative to improve the mechanical properties of brittle polymers with the use of a shape memory polymer as a second phase. The blends were produced using polystyrene (PS, brittle matrix) and shape memory polyurethane (PU/MF, second phase). Samples PU/MF were synthesized in aqueous dispersion (PU/MFAGUA), dissolved in THF (PU/MFTHF) and with the incorporation of poly(styrene-co-maleic anhydride) (PU/MFSMA). The properties of the polyurethanes showed a strong relationship with the crystalline fraction of the soft domains. The PU/MFAGUA and the PU/MFTHF exhibited brittle behavior when they were crystallized and ductile behavior after heat treatment for controlling crystallinity. A study of the synthesis medium with the PU/MFAGUA and PU/MFTHF showed that, by replacing the water for THF in the synthesis, a reduction of the crystalline fraction of the polymer was observed. The presence of poly(styrene-co-maleic anhydride) in PU reduced the crystalline fraction and led to a ductile behavior even without heat treatments. The blends were obtained by thermomechanical mixing with / without addition of poly(styrene-co-maleic anhydride). The obtained blend exhibited a high phase separation caused by immiscibility of the blend components. SEM images showed phase morphology formed by an interconnected matrix of PS (structural component) containing areas of PU whose geometry and dimensions vary with concentration. The mechanical tests showed an increase in impact strength with heat treatment suggesting that shape memory effect was activated. The addition of a second phase that have shape memory is presented as an alternative for improving the mechanical properties of brittle polymers.

O resíduo de catalisador de petróleo (RC) foi caracterizado e quimicamente modificado com 3-aminopropiltrietoxisilano para ser aplicado como material adsorvente não convencional na contenção de petróleo e hidrocarbonetos derramados no mar, tendo sido usado óleo de girassol como modelo para o estudo. O RC apresentou expressiva área superficial específica (150±15 m2/g) e potencial de utilização como adsorvente. Para investigar formas de mitigar a contaminação da água por agrotóxicos, foram desenvolvidas espumas de poliuretano (PUF) baseadas em recursos naturais contendo diferentes quantidades do resíduo RC e testadas como adsorventes em soluções aquosas com clorobenzeno e os pesticidas atrazina (ATZ) e trifluralin (TFL), causadores de impactos negativos sobre o meio ambiente e saúde humana. Os adsorventes foram caracterizados por análise termogravimétrica, microscopia eletrônica, espectroscopia de raios X por dispersão de energia, microtomografia de raios X, espectroscopia na região do infravermelho, difração de raios X e medida de ângulo de contato. As cargas superficiais de PUF e RC foram avaliadas pelo potencial zeta. A adsorção da ATZ foi investigada em função da composição da espuma, concentração inicial do contaminante, pH da solução, método utilizado na preparação do compósito de poliuretano e tempo de contato. Estudos de cinética da ATZ se ajustaram ao modelo de pseudoprimeira-ordem e o processo de equilíbrio foi bem ajustado pelo modelo da isoterma de Freundlich. Os resultados mostraram que a porosidade, o tamanho dos poros e a interconectividade dos poros dos adsorventes preparados foram adequados para a remoção dos contaminantes. Em pH igual a 2, as espumas com elevado teor de RC obtiveram maiores eficiências de remoção de ATZ (25%) comparado ao PUF puro (12%). Por outro lado, a remoção de ATZ foi desfavorecida em pH elevado, o que foi atribuído a interações restritas de ATZ devido a mudanças na carga de superfície do adsorvente. A dessorção de ATZ foi mais efetiva em pH elevado, possibilitando a regeneração e reutilização dos adsorventes. A presença de outras espécies, como a pectina, não interferiu na remoção da atrazina e, portanto, o método proposto sugere também ser adequado na remoção do contaminante em alimentos. O compósito com alta quantidade de RC incorporado na espuma (PUF80) apresentou elevada eficiência de remoção (39%) do trifluralin em soluções aquosas com baixos pHs e a dessorção apresentou melhor comportamento em pHs elevados The petroleum cracking catalyst residue (RC) was characterized and chemically modified with 3-aminopropyltriethoxysilane in order to be applied as an unconventional adsorbent material in leaked oil and hydrocarbons containment in the sea, and sunflower oil was used in the study. RC showed a high specific superficial area (150±15 m2/g) and a potential use as an adsorbent. To investigate ways of mitigating the contamination of water with pesticides, natural resource-based polyurethane foams (PUF) containing different amounts of RC were tested as adsorbents in aqueous solutions with chlorobenzene and the pesticides atrazine (ATZ) and trifluralin (TFL), both responsible for negative impacts on the environment and on human health. The adsorbents were characterized by thermogravimetric analysis, scanning electron microscopy, energydispersive X-ray spectroscopy, X-ray microtomography, infrared spectroscopy, X-ray diffraction and contact angle. PUF and RC surface charges were evaluated by their zeta potential. ATZ adsorption was investigated as a function of the foam composition, initial contaminant concentration, solution pH, polyurethane preparation method and time of contact. ATZ kinetics results were fitted in the pseudofirst-order model and the equilibrium process was well adjusted by the Freundlich isotherm model. The results showed that the adsorbents porosity, pore size and pore interconnectivity were adequate for the contaminants removal. At pH 2, foams with high RC content obtained higher efficiency rates of ATZ removal (25%) compared to PUF (12%). On the other hand, ATZ removal was disfavored at a high pH, which was attributed to restricted ATZ interactions due to changes in the adsorbent surface charge. ATZ desorption was more effective at a high pH, allowing the regeneration and reuse of the adsorbents. The presence of other species, such as pectin, did not interfere with the removal of atrazine and, therefore, the proposed method also suggested to be adequate in the removal of the contaminant in food. The composite with a high amount of RC incorporated in the foam (PUF80) presented high removal efficiency (39%) of trifluralin in aqueous solutions with low pHs and the desorption was enhanced at higher pHs