Polyethersulfone (PES) hollow fiber membranes were produced, containing 3% of two types of clay (Brasgel PA - MMT and Cloisite NA - CLNa), in order to modify the characteristics of the polyethersulfone membrane. By means of the X-ray diffraction, it was possible to observe an exfoliated and/or partially exfoliated structure in the membranes containing clay. From the analysis of contact angle, it was possible to notice an increase in the hydrophilicity of the membrane with the introduction of the clay. Through scanning electron microscopy (SEM), the morphology of the porous support of the membrane was modified with addition of clay, favoring greater uniformity of the pores and fingers. In the flow measurements with distilled water, the membranes with clay obtained the highest flows, being the greater flow with the Cloisite Na clay (~22 L/h.m2) and was in agreement with the contact angle results. In the analysis of permeation with the oily emulsion, the membrane with Brasgel PA clay in its structure presented the greatest flow (~16 L/h.m2) and the membrane with Cloisite Na presented the greatest yield (78.28%). Therefore, the clay acted by modifying both the morphology and the hydrophilicity of the polyethersulfone membrane, improving flow and yield.

RESUMO As membranas poliméricas vêm sendo bastante utilizadas no processo de tratamento de efluentes em todo mundo, solucionando problemas médicos, sociais e ambientais. Sendo assim, membranas de fibra oca foram produzidas a partir da polietersulfona (PES), adicionando a argila Cloisite Na – CLNa e também inserindo o solvente N,N dimetilformamida (DMF), com o intuito de modificar a morfologia da membrana. A argila foi caracterizada por fluorescência de raios-X (FRX) e difração de raios-X (DRX). Por FRX, ficou visto que a argila apresentou característica naturalmente sódica e com pouco materiais acessórios. O DRX mostrou que a Cloisite Na possui característica de uma argila montmorilonita contendo íons Na+. As membranas foram caracterizadas por ângulo de contato (membrana plana), microscopia eletrônica de varredura (MEV) e medidas de fluxo. Por meio das medidas do ângulo de contato foi visto que a presença de argila favoreceu a um aumento da hidrofilicidade das membranas. Nas membranas de fibra oca, foi observado por MEV que a presença da argila modificou a morfologia da membrana, alterando a uniformidade dos “fingers” e dos macroporos e modificando a camada densa no centro do suporte poroso, A adição do ácido no líquido interno modificou ainda mais a morfologia, diminuindo a camada densa no centro do suporte poroso da membrana e também alterando os “fingers” e os macroporos, tendo uma maior uniformidade dos mesmos em relação a membrana sem a presença do DMF no líquido interno. A partir das medidas de fluxo foi possível observar que a membrana contendo 5% de CLNa com a presença do solvente no líquido interno obteve um maior fluxo com o tempo, isto ocorreu devido à morfologia mais uniforme apresentada da membrana.

ABSTRACT Polymer membranes have been widely used in the treatment of effluents worldwide, solving medical, social and environmental problems. Thus, hollow fiber membranes were produced from polyethersulfone (PES) with adding Cloisite Na -CLNa clay and also by inserting the N, N -dimethylformamide (DMF) solvent, in order to modify the membrane morphology. Clay was characterized by X-ray fluorescence (FRX) and X-ray diffraction (XRD). By FRX, it was seen that the clay presented naturally sodium and with little accessory materials. The XRD showed that Cloisite Na has a characteristic of a montmorillonite clay containing Na+. The membranes were characterized by contact angle (flat membrane), scanning electron microscopy (SEM) and flow measurements. By means of the contact angle measurements it was seen that the presence of clay favored an increase the hydrophilicity of the membranes. At the hollow fiber membranes, it was observed by SEM that the presence of clay modified the membrane morphology, changing the uniformity of the “fingers” and the macropores and modifying the dense layer in the center of the porous support. The addition of the acid in the internal liquid modified even more the morphology, decreasing the dense layer at the center of the membrane porous support and also changing the “fingers” and the macropores, having a greater uniformity of the same with respect to the membrane without the presence of DMF in the internal liquid. From the flow measurements it was possible to observe that the membrane containing 5% CLNa with the presence of the solvent in the internal liquid obtained a greater flow over time, this occurred due to the presented more uniform morphology of the membrane.

RESUMO As membranas poliméricas vêm sendo bastante utilizadas no processo de tratamento de efluentes em todo mundo, solucionando problemas médicos, sociais e ambientais. Sendo assim, membranas de fibra oca foram produzidas a partir da polietersulfona (PES), adicionando a argila Cloisite Na – CLNa e também inserindo o solvente N,N dimetilformamida (DMF), com o intuito de modificar a morfologia da membrana. A argila foi caracterizada por fluorescência de raios-X (FRX) e difração de raios-X (DRX). Por FRX, ficou visto que a argila apresentou característica naturalmente sódica e com pouco materiais acessórios. O DRX mostrou que a Cloisite Na possui característica de uma argila montmorilonita contendo íons Na+. As membranas foram caracterizadas por ângulo de contato (membrana plana), microscopia eletrônica de varredura (MEV) e medidas de fluxo. Por meio das medidas do ângulo de contato foi visto que a presença de argila favoreceu a um aumento da hidrofilicidade das membranas. Nas membranas de fibra oca, foi observado por MEV que a presença da argila modificou a morfologia da membrana, alterando a uniformidade dos “fingers” e dos macroporos e modificando a camada densa no centro do suporte poroso, A adição do ácido no líquido interno modificou ainda mais a morfologia, diminuindo a camada densa no centro do suporte poroso da membrana e também alterando os “fingers” e os macroporos, tendo uma maior uniformidade dos mesmos em relação a membrana sem a presença do DMF no líquido interno. A partir das medidas de fluxo foi possível observar que a membrana contendo 5% de CLNa com a presença do solvente no líquido interno obteve um maior fluxo com o tempo, isto ocorreu devido à morfologia mais uniforme apresentada da membrana.

ABSTRACT Polymer membranes have been widely used in the treatment of effluents worldwide, solving medical, social and environmental problems. Thus, hollow fiber membranes were produced from polyethersulfone (PES) with adding Cloisite Na -CLNa clay and also by inserting the N, N dimethylformamide (DMF) solvent, in order to modify the membrane morphology. Clay was characterized by X-ray fluorescence (FRX) and X-ray diffraction (XRD). By FRX, it was seen that the clay presented naturally sodium and with little accessory materials. The XRD showed that Cloisite Na has a characteristic of a montmorillonite clay containing Na+. The membranes were characterized by contact angle (flat membrane), scanning electron microscopy (SEM) and flow measurements. By means of the contact angle measurements it was seen that the presence of clay favored an increase the hydrophilicity of the membranes. At the hollow fiber membranes, it was observed by SEM that the presence of clay modified the membrane morphology, changing the uniformity of the “fingers” and the macropores and modifying the dense layer in the center of the porous support. The addition of the acid in the internal liquid modified even more the morphology, decreasing the dense layer at the center of the membrane porous support and also changing the “fingers” and the macropores, having a greater uniformity of the same with respect to the membrane without the presence of DMF in the internal liquid. From the flow measurements it was possible to observe that the membrane containing 5% CLNa with the presence of the solvent in the internal liquid obtained a greater flow over time, this occurred due to the presented more uniform morphology of the membrane.

Resumo Nesta pesquisa, nanocompósitos de polietileno de alta densidade (PEAD) com argila montmorilonita (MMT) e argila organofílica (OMMT) foram preparados pelo método de intercalação por fusão, com o objetivo de examinar o efeito antichama do material obtido. Para fins de comparação, utilizou-se um produto comercial retardante de chama (RCP) na matriz de PEAD. O polietileno enxertado com anidrido maleico (PE-g-MA) foi utilizado como um compatibilizante dos sistemas. O PEAD e seus sistemas foram avaliados por difração de raios-X (DRX), inflamabilidade (UL94HB, índice de oxigênio (LOI) e calorimetria de cone). Os difratogramas de raios-X ilustraram que provavelmente ocorreu intercalação e/ou esfoliação parcial, com a formação de nanocompósito e/ou microcompósito. Os resultados obtidos para o índice de oxigênio mostraram que tanto o PEAD como seus sistemas apresentaram propriedades retardantes de chama. Por meio dos ensaios de inflamabilidade horizontal, verificou-se que a presença de 1% de argila MMT reduziu em 25% a inflamabilidade de PEAD e, por calorimetria de cone foi visto que a argila OMMT com percentagem de 3, 6 e 9% atuou reduzindo também a inflamabilidade dos nanocompósitos.

Abstract In this research, nanocomposites of high density polyethylene (HDPE) with montmorillonite clay (MMT) and organoclay (OMMT) were prepared by melt intercalation, in order to examine the flame retardant effect of the obtained material. For comparison, a commercial flame retardant product (FRP) was used in the PE matrix. Grafted polyethylene with maleic anhydride (PE-g-MA) was used as a compatibilizer of the systems. HDPE and its systems were evaluated by: X-ray diffraction (XRD), and flammability (UL94HB, oxygen index (LOI) and Cone Calorimetry). The XRD patterns illustrated that probably partial intercalation and exfoliation occurred with the formation of nanocomposite and/or microcomposite. The results obtained for the oxygen index revealed that HDPE and its systems presented flame retardant properties. Through horizontal flammability tests, it was found that the presence of 1% MMT clay reduced 25% of the flammability of HDPE. By Cone Calorimetry was found that the OMMT clay with percentage of 3, 6 and 9% acted reducing the flammability of nanocomposites.

RESUMO Membranas podem ser consideradas películas poliméricas ou inorgânicas que funcionam como uma barreira semipermeável para uma filtração em escala molecular, separando duas fases e restringindo, total ou parcialmente, o transporte de uma ou várias espécies químicas (solutos) presentes na solução. Portanto, o objetivo deste trabalho é produzir membranas de poliétersulfona (PES) e poliétersulfona / argila pela técnica de inversão de fase e avaliar a presença de argila na obtenção de membranas para o tratamento de efluentes líquidos. O solvente utilizado foi a dimetilformamida (DMF) e argilas utilizadas foram Brasgel PA (MMT) e Cloisite Na (CL Na) nas proporções de 3 a 5% (em peso). Por difração de raios-X (DRX), as membranas com 3% das argilas MMT e CL Na aparentemente apresentaram estruturas parcialmente esfoliadas; para a composição com 5% de CL Na observou-se um pequeno pico, que indica que esta é, possivelmente, uma estrutura intercalada ou microcompósito. A partir dos resultados de microscopia eletrônica de varredura (MEV), visualizou-se que a superfície da membrana de PES puro apresentou uma estrutura aparentemente sem poros, no aumento utilizado e, uma superfície sem rugosidade quando comparada com às membranas com argila. As medidas de ângulo de contato indicaram que a inclusão da argila alterou a capacidade de molhamento das membranas. O fluxo com água destilada para todas as membranas iniciou alto e ao longo do tempo chegou a um patamar de estabilização. Assim, pôde-se concluir que a presença e o teor de argila alteraram a morfologia da membrana, contribuindo para um aumento do fluxo de água.

ABSTRACT Membranes can be considered polymeric or inorganic films that function as a semipermeable barrier to filtration on a molecular scale, separating two phases and restricting, totally or partially, the transportation of one or more chemical species (solute) present in the solution. Therefore, the aim of this work is to produce polyethersulfone membranes (PES) and polyethersulfone/clay by phase inversion technique and evaluate the presence of clay in obtaining membranes for wastewater treatment. The used solvent was dimethylformamide (DMF) and clays were Brasgel PA (MMT) and Cloisite Na (CL Na) in the proportion of 3 to 5% (wt.). By X-ray diffraction (XRD), the membranes with 3% of MMT and CL Na clays apparently had partially exfoliated structures. For the composition with 5% of CL Na a small peak was observed, which indicates that this is possibly an intercalated structure or microcomposite. By scanning electron microscopy (SEM), visualizes that the pure suface of the pure PES membrane a structure apparently without pores was observed in the used magnification and without roughness surface when compared to membranes with clay. The measurements of contact angle indicated that the inclusion of clay altered the wetting ability of the membranes. The flow with distilled water for all membranes started high and over time reached a stabilization level. Thus, it can be concluded that the presence and the content of clay altered the morphology of the membrane, contributing to an increase in water flow.

Membranes of polyamide 6 and its nanocomposites with 3 and 5% of clay were obtained by the phase inversion method using distilled water and solvent as the coagulation bath, 10 and 30% of acid was used, in order to change the membranes morphology/porosity. By XRD analysis, the obtained nanocomposites showed an exfoliated and/or partially exfoliated structure, it was also seen two characteristics peaks of the polyamide 6 phases (α and γ). For the membranes, the characteristic peak γ of the membrane disappeared, being evident the peaks α1 and α2. By SEM the PA6 membrane almost doesn't have pores in its surface, with an addition of clay had an increase in the quantity of surface pores. In the cross section of the PA6 membrane, an extremely thin selective layer, adding the clay the selective layer became thicker and a better defined porous support was obtained. From the acid in the coagulation bath the PA6 membrane continued with a few pores structure. For the nanocomposites there was an increase in size and a better uniformity of the pores. In the cross section the presence of the bath decrease the membrane filtering, also modifying a uniformity of the pores.

Abstract Polymer/clay nanocomposites are a new class of composites with polymer matrices where the disperse phase is a silicate with elementary particles that have at least one of dimensions in nanometer order. Polyamide 6/Brazilian organoclay nanocomposites were prepared by melt intercalation, and the mechanical, thermal and thermomechanical properties were studied. The structure and morphology of the nanocomposites were evaluated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). It was verified by XRD and TEM analysis that all systems presented exfoliated structure predominantly. By thermogravimetry (TG), nanocomposites showed higher stabilities in relation to pure polymer. It was observed that the nanocomposites showed better mechanical properties compared to the properties of polyamide 6. The heat deflection temperature (HDT) values of the nanocomposites showed a significant increase in relation to pure polymer.

A mistura de polímeros diferentes possibilita a obtenção de novos materiais com propriedades, na maioria das vezes superiores às dos componentes puros. Essa mistura vem sendo utilizada e aplicada na obtenção de membranas com intuito de melhorar as propriedades de barreira para que se possa separar duas fases restringindo total ou parcialmente o transporte de uma ou várias espécies químicas presentes. Neste trabalho, membranas poliméricas foram obtidas a partir de blendas de poliamida 6 (PA6), polipropileno (PP) e compatibilizantes pelo método de inversão de fases, com a finalidade de serem utilizadas em processos de separação, purificação, fracionamento e contração. Estas foram estudadas por difração de Raios-X (DRX), calorimetria exploratória diferencial (DSC) e microscopia eletrônica de varredura (MEV). Os resultados de DRX evidenciaram a presença dos picos característicos de reflexão da PA6, PP e dos compatibilizantes. Por DSC, observou-se que a presença do compatibilizante não promoveu alterações significativas na cristalinidade da PA6. Por meio das fotomicrografias de MEV, visualizou-se a obtenção de membranas microporosas assimétricas, como também percebeu-se que a presença da segunda fase na PA6 modificou a morfologia das membranas.

The mixture of different polymers enables obtaining new materials with properties most often superior to those of the pure components. This mixture is being used and applied in obtaining membranes with a view to improving the barrier properties, so that it can separate two phases wholly or partially, restricting the transport of one or more chemical species. In this work, polymer membranes were obtained from blends of polyamide 6 (PA6) and polypropylene (PP), compatibilizing by the method of phase inversion, for being used in processes of separation, purification, fractionation and contraction. These were studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). XRD results showed the presence of peaks characteristic of PA6, PP and compatibilizers. For DSC, it was observed that the presence of the compatibilizer did not cause significant changes in crystallinity of PA6. Through the SEM photomicrographs is confirmed the production of asymmetric microporous membranes and the presence of the second modified PA6 phase in the morphology of the membranes is also noted.

Nanocompósitos de poliamida 6 com argila organofílica foram preparados pelo método de intercalação no estado fundido. Foram estudadas as propriedades reológicas e mecânicas de nanocompósitos com argila nacional. A argila utilizada foi tratada com o sal quaternário de amônio (Cetremide) e foi caracterizada por Espectroscopia no Infravermelho (FTIR) e difração de raios X (DRX). Os resultados evidenciaram a incorporação do sal na argila e sua organofilização. Para a obtenção dos nanocompósitos, foram preparados concentrados de PA6/argila (1:1) em (m/m) e estes foram adicionados na poliamida 6, em quantidade de 3% de argila no composto final, utilizando uma extrusora de rosca dupla corrotacional. Posteriormente, as amostras foram moldadas por injeção e caracterizadas por: reometria capilar, DRX, MET e ensaios mecânicos (tração e impacto). Os resultados de reometria capilar mostraram que a presença da argila organofílica na PA6 aumentou a viscosidade dos sistemas. Por DRX e MET, foi verificado que todos os sistemas apresentaram predominância de estrutura esfoliada. As propriedades mecânicas sob tração foram melhores do que as da poliamida 6.

Nanocomposites of polyamide 6 with organoclay were prepared by melt intercalation and their rheological and mechanical properties were studied. The clay was treated with the quaternary ammonium salt (Cetremide) and characterized by Infrared Spectroscopy (FTIR) and X-ray diffraction (XRD). The results showed the incorporation of salt in the clay and its organophilization. A master was prepared with PA6/clay (1:1) by weight and this was added to the pure polyamide 6 to reach the nominal proportion of 3% of clay, using a corrotacional twin screw extruder. The samples were molded by injection and characterized by: capillary rheometry, XRD, TEM and mechanical testing (tensile and impact). The results of capillary rheometry showed that the presence of organoclay in the PA6 increased the viscosity of the systems. With XRD and TEM, it was verified that all systems presented predominantly exfoliated structure. The tensile properties of the nanocomposites were better than those of pure polyamide 6.

Recent interest in polymer/organoclays nanocomposites systems is motivated by the possibility of achieving enhanced properties and added functionality at lower clay loading as compared to conventional micron size fillers. By adding montmorillonite clay to polyamide 6 increases the Young modulus, yield strength and also improves barrier properties. In this work, nanocomposites of polyamide 6 with montmorillonite clay were obtained. The clay was chemically modified with three different quaternary ammonium salts such as: Dodigen, Genamin and Cetremide. In this case, a dispersion of Na-MMT was stirred and a salt equivalent to 1:1 of cation exchange capacity (CEC) of Na-MMT was added to the dispersion. The montmorillonite clay (untreated and treated by ammonium salts) and nanocomposites were characterized by X ray diffractions. Also the nanocomposites were characterized by transmission electron microscopy and mechanical properties. The results indicated that all the quaternary ammonium salts were intercalated between the layers of clay, leading to an expansion of the interlayer spacing. The obtained nanocomposites showed better mechanical properties when compared to polyamide 6. The clay acted as reinforcing filler, increasing the rigidity of nanocomposites and decreasing its ductility.