RESUMO Neste estudo, foram avaliadas blendas de polipropileno copolímero (PPCop)/polipropileno reciclado (PPRec), proveniente de baldes industriais pós-consumo, em três proporções diferentes (80:20; 60:40 e 40:60% em peso). As blendas foram avaliadas por índice de fluidez, reometria de torque e reologia em regime dinâmico-oscilatório. Os resultados de índice de fluidez indicaram que a mistura de material reciclado com o PPCop promove uma diminuição da massa molar, em comparação ao PPCop. Por reometria de torque, verificou-se que as blendas melhoraram a processabilidade em comparação ao PPCop. Além disso, as blendas apresentaram estabilidade ao longo do processamento, indicando ausência de degradação para as condições de processos utilizadas. Por meio dos ensaios em regime dinâmico-oscilatório, observou-se que, em baixas frequências (< 1 rad/s), o PPCop e as blendas (PPCop/PPRec) apresentam um comportamento de fluido Newtoniano, enquanto que, para frequências maiores que 1 rad/s, um comportamento de fluido pseudoplástico. Os valores dos pontos de intersecção (G’ = G”) das curvas de módulo de armazenamento (G’) e de módulo de perda (G’’), em função da frequência angular (ω), indicaram que as blendas apresentaram uma redução da massa molar, sendo mais pronunciada na composição contendo 60% de PPRec. Os resultados reológicos das blendas PPCop/PPRec foram de grande relevância, uma vez que permitem analisar o comportamento de blendas contendo material reciclado.

ABSTRACT In this study, blends of copolymer polypropylene (PPCop /recycled polypropylene (PPRec) from industrial containers after consumption were evaluated in three different ratios (80:20, 60:40 and 40:60 wt.%). The blends were evaluated by melt flow index, torque rheometry and rheology in a dynamic oscillatory regime. The results from the melt flow index indicated that the blending of recycled material with PPCop causes a decrease in the molecular weight as compared to PPCop. By torque rheometry, it was verified that the blends showed improved processability in relation to PPCop. Also, the blends showed stability throughout the processing, indicating absence of degradation due to the process conditions used. By the dynamic-oscillatory regime tests, it was observed that, at low frequencies (<1 rad/s), the PPCop and the blends (PPCop / PPRec) demonstrated a Newtonian fluid behavior, whereas, at frequencies greater than 1 rad/s, a pseudoplastic fluid behavior was observed. The values of the intersection points (G ‘= G”) of the storage modulus curves (G’) and loss modulus (G’), as a function of the angular frequency (ω) indicated that the blends showed a reduction of the molecular weight, which was more pronounced in the composition containing 60% PPRec. The rheological results of the PPCop / PPRec blends were of great relevance, since they allowed the analysis of the blends behavior containing recycled material.

Abstract Researches of polymer blends based on biological and biodegradable polymers appear as a viable alternative to develop environmentally friendly materials. Therefore, the aim of this research was to produce compounds made with biological polyethylene, i.e., Biopolyethylene, Bio-PE, added to the biodegradable Polycaprolactone (PCL) and functionalized by the copolymer of polyethylene grafted with acrylic acid (PEgAA), to obtain better mechanical properties and toughen Bio-PE. Compounds were processed in a co-rotating twin screw extruder and sample tests were injection molded. The compositions investigated were: Bio-PE/PCL at 90/10, 80/20 and 70/30 wt.% without compatibilizer and upon addition of 10 phr (parts per hundred of resin) of PEgAA. The blends were characterized by X-ray diffraction (XRD), impact strength, heat deflection temperature (HDT) and scanning electron microscopy (SEM). Through XRD, it was observed that addition of PCL and PEgAA did not significantly change Bio-PE diffraction patterns. Impact strength data showed that the blends presented a tougher behavior upon addition of PCL and PEgAA. The HDT of compatibilized blend with 20wt.% of PCL was slightly higher. SEM images of compatibilized blends showed lower average particle diameters as well as absence of coalescence and aggregates.

Abstract Blends of Polystyrene (PS) and Poly(ε-caprolactone) (PCL) were twin screw extruded, two PSs, with low and high melt flow rate (MFR) were used and their feasibility within PCL investigated by means of torque rheometry, mechanical tests, heat deflection temperature (HDT) and scanning electron microscopy (SEM); predictive models were utilized to evaluate interfacial adhesion in PS/PCL blends. Results show that no decreasing was verified in torque rheometry plots suggesting thermally stable blends; elastic modulus decreased and elongation at break increased in PS/PCL blends compared to neat PS. PS/PCL blends with low MFR PS and higher PCL amount are more thermodynamically stable. Higher HDT was verified in PS/PCL blends. The trends observed applying predictive models are indicative of poor adhesion between PCL and PS, agreeing with coalescence and phase segregation as verified in SEM images. PS/PCL systems with higher MFR PS presented the best results.

In this work, compounds based on two grades of polypropylene (PP), i.e., PP H503 or PP H103 with residues of Big bag fabrics (RBB) were processed in a corrotational twin screw extruder with RBB content ranging from 10% to 50% of the weight. Then, their thermal properties were investigated through Differential Scanning Calorimetry (DSC) and Thermogravimetry (TG); mechanical by tensile and impact; thermomechanic by heat deflection temperature (HDT); and their morphology by Scanning Electron Microscopy (SEM). With the aim to add maximum RBB content without considerable damage to the properties of neat PPs, it was observed that addition of 10%, 30% and 50% of RBB did not significantly interfere in the PP matrices, being the compound PP + 30% RBB which one presented more successful properties, leading to reused compounds with higher performance and lower costs at same time.

The development of ceramic membranes with different geometries and compositions extends the possibilities of industrial applications, inducing advantages in terms of increased permeability, membrane area by volume module and chemical, thermal and mechanical resistance. The use of low-cost raw materials is a trend that has grown in scientific research. The aim of this work is to prepare membranes with hollow fiber geometry from alumina and residue of quartzite, by the technique of immersion precipitation in distilled water from a mixture of ceramic mass with a solution of polyethersulfone and, synthesized in temperatures of 1100 ºC to 1500 °C. The hollow fiber membranes were characterized by chemical analysis, X-ray diffraction, particle size distribution, scanning electron microscopy, apparent porosity, flexural strength and permeated water flow by the membranes. The results indicated that the sintering temperature has direct influence on the formation of the mullite phase, and the properties of apparent porosity and permeate flow. The higher the sintering temperature (1400-1500 ° C) increase the formation of the mullite phase, the lower the porosity, as well as the lower the permeate water flow in the membranes. However, there was increase in flexural strength in the hollow fiber membranes with high temperature.

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 Este trabalho teve como objetivo avaliar o envelhecimento termo-oxidativo, nas propriedades mecânicas e de índice de amarelamento (YI), de blendas de poliestireno com borracha reciclada (SBRr), compatibilizadas. As blendas foram preparadas, inicialmente, em uma extrusora de rosca dupla corrotacional e, posteriormente, os grânulos extrudados foram moldados por injeção. Para efeito comparativo, o poliestireno de alto impacto comercial (HIPS) foi processado nas mesmas condições das blendas. Os resultados da caracterização do SBRr indicaram, em sua composição, cargas de sílica, carbonato de cálcio, talco e óxido de zinco, enquanto que, por termogravimetria, verificou-se duas etapas de decomposição térmica. Verificou-se que a resistência ao impacto diminuiu, significativamente, nos 15 dias iniciais do envelhecimento, e, subsequentemente, apresentou uma tendência de estabilização com pequenas oscilações. As propriedades de módulo de elasticidade, resistência e alongamento na ruptura sob tração apresentaram o mesmo comportamento da resistência ao impacto, redução acentuada nos 15 dias inicias, seguida de estabilização, com o decorrer do envelhecimento. Quando a blenda foi compatibilizada com 5% de estireno-butadieno-estireno (SBS), foram observadas as melhores propriedades, antes e após o envelhecimento, apresentando resistência ao impacto equiparáveis ao HIPS. A perda de massa das blendas indicou extração de componentes voláteis. Por índice de amarelamento (YI), observou-se, nas blendas, um aumento brusco nos 15 dias iniciais e, em seguida, estabilidade, com uma taxa de amarelamento praticamente constante. Até 30 dias de envelhecimento, o HIPS apresentou uma baixa taxa de amarelamento, e, posteriormente, ocorreu uma intensificação no YI. No geral, as blendas obtidas por mistura mecânica apresentaram comportamento similar ao HIPS. Porém, somente quando a blenda foi compatibilizada com SBS que o comportamento de impacto apresentou o mesmo patamar do HIPS.

ABSTRACT The objective of this study was to evaluate thermo-oxidative aging in the mechanical properties and yellowing index (YI) of polystyrene blends with compatibilized recycled rubber (SBRr). The blends were initially prepared in a co-rotating double screw extruder, after which the extruded granules were injection molded; high-impact polystyrene (HIPS) was processed under the same conditions for comparison. The SBRr characterization results revealed composition fillers of silica, calcium carbonate, talc, and zinc oxide, while thermogravimetry demonstrated two thermal decomposition stages. It was found that impact strength decreased significantly during the initial 15 days of aging and then showed a tendency to stabilize with small oscillations. Properties related to the modulus of elasticity, strength, and elongation at tensile rupture were similar to those of impact strength: a marked reduction in the initial 15 days followed by stabilization with aging. When a blend was compatibilized with 5% styrene-butadiene-styrene (SBS), optimal properties were observed before and after aging, indicating impact resistance comparable to HIPS. The blends’ loss of mass suggested volatile component extraction. In terms of the YI, the blends showed a sudden increase in the first 15 days of aging before stabilizing at a practically constant yellowing rate. Up to 30 days of aging, HIPS presented a low yellowing rate, after which point the YI intensified. In general, the blends obtained via mechanical mixing exhibited behavior similar to HIPS; for the blend compatibilized with SBS, however, the impact behavior was identical to that of HIPS.

Biodegradable Poly (ɛ-caprolactone) (PCL) was compounded with Brasgel PA (MMT) and Cloisite Na (CLNa), and compatibilized with maleic anhydride grafted poly(ɛ-caprolactone) (PCL-g-MA). No evidence of degradation was verified during processing, as well as particle aggregates were absent as displayed through scanning electron microscopy (SEM) images. Compatibilized compounds upon clay addition achieved higher thermal stability as visualized by thermogravimetry (TG). Montmorillonite clays acted as nucleant agent during PCL melt crystallization as evidenced by differential scanning calorimetry (DSC). Mechanical behavior of PCL was preserved, and all compounds presented Elongation higher than 350% meanwhile the heat distortion temperature (HDT) was increased by 20% in PCL compounds, which may have wider range of application and better performance.

Abstract The objective of this study was to develop bionanocomposites from blends of poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) and from 3% and 6% bentonite clay. Initially, the bentonite clay was treated with Praepagen salt, and the properties of the modified clay were evaluated. After the organophilization of the clay was completed, 50:50 blends of PLA/PBAT were prepared, and 3 and 6% clay was added. To test the dispersion of the system, the blending sequence was performed using eight different sequences for the addition of clay to the PLA/PBAT matrices. The mixtures were prepared in a twin screw extruder, and the specimens were subsequently injection molded. The investigated mechanical and morphological properties included the yield strength, yield strain, tensile and bending elastic modulus, and scanning and transmission electron microscopy analyses. The results of this study showed increases of the mechanical properties when nanoparticles were added and the formation of bionanocomposites with intercalated structures.

The aim of this work was to prepare hollow fiber membrane changing the composition of polyethersulfone, polyvinylpyrrolidone (PVP) and clay, through the phase inversion technique, evaluating the influence of these constituents on the viscosity and distinct morphologies. Flat membranes were produced and their contact angles were determined and showed difference when clay was added and/or PVP. For the hollow fiber membranes, the +addition of these constituents, PVP and/or clay in the solution, can change significantly the viscosity and effect the membrane formation. From the scanning electron microscopy (SEM) images, it was identified the influence on morphology with the compositional variation of each additive, with the PVP promoting shorter precipitation time, favoring the formation of pores of the “fingers” type and increasing the presence of macrovoids. The addition of clay favored the formation of spherical pores, reducing the presence of macropores.

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.

Abstract In this work, blends based on environmentally friend polymers such as Biopolyethylene (Bio-PE), Polycaprolactone (PCL) and Polyethylene graft maleic anhydride (PEgMA) added as compatibilizer agent were produced by conventional extrusion, aiming to produce bio-blends with synergic properties at low processing cost, being at same time non-polluting and therefore contributing to the environment preservation. Differential scanning calorimetry (DSC) showed that blending does not significantly interfere on the melting and crystallization behaviors of neat polymers, suggesting being low miscibility compounds. Mechanical properties were observed changing with blend composition as the impact strength significantly increased reaching values higher than 130% when compared to neat Bio-PE. Scanning electron microscopy (SEM) images showed honeycomb morphology in Bio-PE/PCL blends, and the addition of PEgMA decreased the coalescence contributing to obtain more stable and synergic compounds. Bio-PE/PCL/PEgMA at 80/20/10 contents presented the best properties and may be used for packaging materials (food containers, film wrapping), and hygiene products.

Abstract The vulcanized rubber waste from the shoe industry causes environmental damage when it is incinerated or inappropriately discarded, turning this into a problem of major concern. Therefore, this study had as the main objective the Polystyrene (PS) toughening using different contents of white vulcanized styrene-butadiene rubber (SBRr) waste produced in the shoe industry. The mixtures were initially prepared in a co-rotational double screw extruder and, thereafter, the extruded granules were injection molded. Analyzed were the rheological, mechanical, thermomechanical properties and morphology of the produced blends. The rheological results showed a viscosity increase as the SBRr concentration was augmented, leading to a higher stability when compared to pure Polystyrene. Verified was an increase of impact resistance of 189% to the blend that contained 50% of SBR rather than pure Polystyrene. On the other hand, the traction properties, hardness Shore D, thermal deflection temperature (HDT) and Vicat softening temperature of the blends tended to decrease when compared to pure Polystyrene results. However, as this SBR waste is made up of a complex mixture of SBR, filler, processing additions, curing agents and stabilizers, it probably acted in the sense of not causing such a drastic reduction of the properties, even using a high concentration of SBRr waste. The morphologies obtained with the SEM method (Scanning Electronic Microscope) were quite different and typical of immiscible blends. The results show that it is possible to obtain a new material with good properties, valuing a discarded industrial waste and avoiding environment aggression.

Photodegradation of PCL was performed exposing injected specimens to ultraviolet radiation (UV-B) up to 9 weeks. Photodegradated PCL specimens were tested by Differential Scanning Calorimetry (DSC), Infrared Spectroscopy (FTIR), mechanical properties, Optical Microscopy (MO) and Scanning Electron Microscopy (SEM).Upon exposure decrease in elongation at break and increase of elastic modulus were verified, higher degree of crystallinity was observed for longer exposure what can be due to the chemi-crystallization mechanism. From IR spectra new carbonyl group (C=O) peaks were observed. Presence of micro cracks on specimens’ surface was identified by MO. From morphological analyses is suggested that the photodegradation in PCL takes place by bulk erosion mechanism.

RESUMO Neste trabalho, membranas de polisulfona com adição de 3% em massa de argila montmorilonita natural, sódica e lítio, oriundas do estado da Paraíba, foram desenvolvidas pelo método de inversão de fases. Utilizou-se o N-metil-2 pirrolidona (NMP) como solvente na proporção de 80% e 20% de sólido. As argilas e membranas foram caracterizadas por difração de raios-X (DRX) e espectroscopia na região do infravermelho com transformada de Fourier (FTIR). Além disso, as membranas foram estudadas por microscopia eletrônica de varredura (MEV), porosidade e permeação a vapor d'água, a fim de se estudar seu comportamento para aplicação na separação de gás. Os DRX das argilas evidenciaram bandas de cristalinidade características de montmorilonita. Os difratogramas de DRX das membranas indicaram que possivelmente ocorreu a formação de uma estrutura intercalado/esfoliado devido à ausência das bandas referentes às argilas. Por FTIR das argilas foi visualizado as mesmas bandas características da montmorilonita, diferenciando pelos cátions que foram trocados na estrutura. O FTIR das membranas apresentaram bandas características da polisulfona, e para os híbridos estas bandas podem ser também das argilas por apresentarem as mesmas faixas de número de onda. As fotomicrografias de MEV evidenciaram a formação de uma camada densa na pele filtrante e na parte inferior foi observada uma estrutura de fingers que pode ter influenciado na permeação. O ensaio de porosidade indicou que a presença de argila na membrana reduziu a quantidade de poros e o ensaio de permeação a vapor d'água ilustrou que houve uma diminuição da permeação com a adição de argila em comparação com a membrana de polisulfona pura. A membrana aditivada de argila com lítio apresentou uma redução da permeação a vapor d'água em 53%, indicando melhores propriedades de barreira.

ABSTRACT In the present study, polysulfone membranes with addition of 3% by mass of natural montmorillonite clay, sodic and lithium, from the state of Paraiba, were developed by phase inversion method. The N-methyl-2-pyrrolidone (NMP) was used as a solvent in the proportion of 80% and 20% solid. The clays and membranes were also characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). In addition, the membranes were characterized by scanning electron microscope (SEM), porosity and vapor permeation of water in order to study their behavior in gas separation applications. The XRD of the clays showed peaks of crystallinity characteristic of montmorillonite. The XRD diffractograms of membranes showed that it has possibly occurred the formation of a structure intercalated/exfoliated due to the absence of peaks related clays. By FTIR of the clays were visualized the same bands characteristic of the montmorillonite, differentiating by the cations that were changed in the structure. The FTIR of the membranes presented bands characteristic of polysulfone, and for the hybrids these bands can also be of the clays because they present the same ranges of wave number. The SEM photomicrographs showed the formation of a dense layer on the filter skin and on the inferior surface was observed fingers structures that may have influenced the permeation. The porosity test indicated that the presence of clay in membranes reduced the amount of pores and the permeation test using water vapor showed that there was a decrease in the permeation by adding clay in comparison to pure polysulfone membrane. The membrane with additives of clay with lithium presented a 53% reduction of gas permeation, indicating better barrier properties.