ABSTRACT One of the highlighted areas in the development of new materials is the generation of micro- and nanoparticles as drug carriers which allow the progress in formulations with the ability to release active agents in a controlled way. The proanthocyanidins (PAC) extracted from the bark of the Black Wattle have stood out for their biological activities. However, most polyflavonoids have some features which limit their application in the pharmaceutical field, such as light fastness, low bioavailability of active agents, and unpleasant taste. In this context, this study aims to present the synthesis and characterization of PAC-loaded lactic-co-glycolic acid (PLGA) microparticles obtained by the multiple emulsion method. The incorporation of PAC into PLGA was successfully achieved with PAC encapsulation efficiency around 73%. Spherical microparticles were obtained with a size distribution in the range of 0.6 to 2.4 μm. The presence of PAC modified the thermal properties of the PLGA matrix. The results of in vitro assays with Vero and T24 lineage celss showed that PLGA/PAC microparticles did not promote any effect on cell proliferation by MTT assay after 24 h. The novel Acacia mearnsii proanthocyanidin-loaded PLGA microparticles have potential for application in biological systems.

ABSTRACT Aqueous amine solutions are benchmark solvents for CO2 capture and their operational drawbacks are well-known. In order to overcome these problems, the support of amines on solid materials appears as an option for CO2 capture. Cellulose is a versatile and low-cost material that can be used as a support. This study reports chemical modification of cellulose fibers extracted from rice husk with different amines and their potential for CO2 capture. The obtained compounds were characterized by different techniques. The CO2 sorption capacity was gravimetrically assessed in a Magnetic Suspension Balance. Quantum mechanical simulations and experimental results revealed that -NH- and -NH2 represent major working sites of the employed compounds. The best result for CO2 sorption was attained for the amine-modified cellulose CL-D-400 with a sorption capacity of 409 µmol CO2/g at 1 bar and 1091 µmol CO2/g at 10 bar with amine concentrations as low as 2 × 10- 6 mol/mg.

Ionic liquids (ILs) physical immobilization in solid materials is a key strategy for developing efficient and low cost CO2 capture processes. In this work, two porous commercial substrates with different characteristics (silica and alumina) were impregnated with ILs by physical wet method. Imidazolium based IL combined with [Br]- and [Tf2N]- anions were used in impregnation process. CO2 sorption capacity and selectivity (CO2/N2) of these materials were investigated. The best results regarding CO2/N2 selectivity and CO2 sorption were obtained with [Tf2N]- anion. In relation to solid support, commercial alumina exhibited enhanced CO2 uptake and higher selective capacity (CO2/N2) (6.1 (± 0.1)). Combination of commercial alumina as support and 20 wt% of mbmim [Tf2N] resulted in higher CO2/N2 selectivity of 9.5 ± 1.0. In addition, this material also showed fast sorption kinetics when compared to pure IL besides reuse capacity.

The development of both versatile and inexpensive sorbents for CO2/CH4 separation has become one of the greatest challenges to the environment and natural gas processing. This study reports the preparation and characterization of polyurethane (PU)/ cellulose based poly(ionic liquid)(CPIL) composites for CO2/CH4 separation. PU matrix was reinforced with CPIL in the range of 10-30 wt%. Several characterization techniques (TGA, DSC, DMTA and FESEM ) were used to study the physical properties of composites when the PU matrix is reinforced with cellulose based poly (ionic liquids) (CPIL) up to 30%. CO2 sorption, reusability and CO2/CH4 selectivity were assessed by pressure-decay technique. Results showed that CPIL addition in PU matrix promoted the increase in both thermal stability and mechanical properties when compared to PU. The best result for CO2 sorption (35.0 mgCO2/g) was obtained for PU/CPIL-TBP 10% which presented a higher sorption value when compared to PU (24.1 mgCO2/g) and PU/CELLULOSE 10% (26.8 mgCO2/g). PU/CPIL-TBP 20% demonstrated higher CO2/CH4 selectivity. PU/CPIL composites appear as promissory materials for CO2 capture. These compounds combine the benefits of ionic liquids (ILs) (high ionic conductivity, chemical and thermal stability) and cellulose (thermal stability) with PU properties (mechanical stability, processing and tunable macromolecular design).

Abstract: Waterborne polyurethanes (WPUs) are interesting materials for coatings when compared to solvent-based polyurethanes, once that reducing the concentration of volatile organic compounds that are harmful for human health and the environment. However, the WPU has low weathering resistance. In order to improve this behavior among others properties, inorganic fillers has been added in these systems. SiO2 particles from various sources, mainly, from agro-industrial waste, as rice husk has attracted the scientific and technological interest. In this study, the accelerated weathering essay was performed in waterborne polyurethane (WPU)/ silica (from rice husk ash) composites in order to evaluate the thermal and physical changes in these materials. These composites were prepared by two distinct methods: in situ polymerization and blending method. The highest resistance to thermal degradation and to accelerated weathering was reached with WPU/silica composites obtained by blending method due the interactions between SiO2 particles and the polymer matrices. Blending method for preparation WPU/silica composites proved to be a simpler and faster method, with no drawback for large scale application.

Capturing carbon dioxide (CO2) from exhaust gases is an important strategy to prevent climate change. There is a great interest in developing novel CO2 sorbents. Thus, a series of polyurethane (PU) / silica xerogels functionalized with RTILs (bmim Cl and bmim TF2N) composites were prepared and characterized. PU matrix was reinforced with functionalized silica xerogels in the range of 0.5-20 wt%. PU / functionalized silica xerogels were characterized by NMR, FTIR, DSC, TGA, DMTA and FESEM. CO2 sorption capacity and reusability were assessed by the pressure-decay technique at 298.15 K and 1 bar. Results showed that the filler aggregation in PU matrix promoted the reduction of mechanical properties. However, addition of silica xerogels functionalized with RTILs in PU matrix led to increased CO2 uptake. CO2 sorption capacity tends to increase with the incorporation of silica xerogels functionalized with RTILs in PU matrix. The best CO2 sorption value was found for PU/SX-[Bmim]-[TF2N] 0.5 composite (48.5 mgCO2/g at 298.15 K and 1 bar). Moreover, the PU/SX-[Bmim]-[TF2N] 0.5 composite showed reuse capacity and higher CO2 sorption value as compared to other reported composites.

The study of environmentally friendly CO2 sorption agents are growing due to the need of mitigate this gas from atmosphere. Ionic Liquids (ILs) present the advantage of having low vapor pressures and being chemically and thermally stable. Besides, their properties can be designed by varying the groups of the cation or anion. Yet, these compounds present a lower desorption energy when compared to amines based chemical solvents. These characteristics make ILs potentially important for the development of new processes focused on the mitigation of global warming. However, ILs have high viscosity and high cost, making them economically unfeasible. To minimize these problems, bubble glass can be used as an additive in ionic liquids to reduce cost and viscosity. Bubble glass has several applications in industry, presenting low cost and high chemical and mechanical resistance. This work evaluated the CO2 solubility in [bmim][BF4] and [mbmim][Tf2N] pure and mixed with boron silicate bubble glass in volumetric concentrations of 5% to 50%. Data are reported at 27 bar of pressure and temperatures of 303 and 323 K. Mixed systems with 50% concentration of bubble glass showed the best sorption results for both ionic liquids.

RESUMO A necessidade de reduzir a quantidade de resíduos plásticos descartada no meio ambiente revela a área de reciclagem como de grande interesse, tendo como uma das alternativas a reciclagem química do poli(tereftalato de etileno) (PET) pós-consumo com poliésteres alifáticos. Portanto, neste trabalho estudou-se a reação em massa do PET pós-consumo com o poli(L-ácido lático) (PLLA), plastificado com trietil citrato de sódio, visando obter novos copoliésteres alifático-aromáticos potencialmente biodegradáveis. A copolimeri zação foi conduzida em reator pela adição de PET (obtido de garrafas de refrigerante) e PLLA (obtido por uma reação de policondensação do L-ácido lático), variando de 10 a 90 % em massa. Em seguida, adicionaram-se os aditivos necessários e verteu-se em formas de silicone, obtendo os copolímeros. A técnica se mostrou adequada para a síntese de PET-co-PLLA, sendo esta confirmada através da análise de RMN 1H. As análises de TGA indicaram que a estabilidade térmica dos copolímeros aumenta conforme aumenta o teor de PET. Após a caracterização dos copolímeros, realizou-se o ensaio de biodegradação, a qual foi acompanhado por RMN 1H, FTIR-ATR, análise visual, MEV, DSC e TGA antes e após 15, 45 e 90 dias enterradas em solo preparado. Os resultados de biodegradação revelaram que a parte alifática dos copolímeros foi a primeira a sofrer biodegradação, indicando assim a preferência dos micro-organismos presentes no solo pelo PLLA. Estes resultados indicaram que é possível sintetizar novos copolímeros a partir de garrafas de refrigerante pós-consumo, potencialmente biodegradáveis quando descartados no meio-ambiente.

ABSTRACT The attempt to reduce the accumulation of plastic waste in the environment shows the recycling as an interesting area and the chemical recycling of poly(ethylene terephthalat) (PET) post-consumer allied to the reaction with aliphatic polyesters one of these methods to help solving this problem. Therefore, this work presents a study of bulk polymerization of PET post-consumer with poly(L-lactic acid) (PLLA), plasticized with sodium triethyl citrate, aiming to obtain new aliphatic-aromatics copolyesters potentially biodegradable. The copolymerization occurred in a glass reactor with N2 atmosphere. Different proportions were added of PET (obtained from soda packaging) and PLLA (obtained by a polycondensation reaction of L-lactic acid), among 10 and 90wt% and the temperature was gradually increased until melting. After that, the additives were added in the fluid mass which was shed in silicone molds. This method was adequate to synthesize copolymers of PET-co-PLLA and it could be confirmed through the 1H RMN analyses. The TGA analyses showed that the thermal stability increases with the raise of PET rate. After the characterization, the soil biodegradation was curried, which was accompanied by NMR 1H, FTIR-ATR visual analyses, SEM, DSC and TGA before and after buried in prepared soil. The results showed that the aliphatic fraction is the first to suffer scission of molecular chain, indicating a preference of the microorganisms from soil to PLLA and this method was adequate to synthesize new copolymers from soda packing post-consumer potentially biodegradable when discarded on environment.

Menthol-loaded PLGA micro/nanospheres were synthesized using the multiple emulsion/solvent evaporation technique. Parameters such as stirring rate, external surfactant content, PLGA/menthol weight ratio, solvent evaporation and lyophilization time were evaluated as well as the degradation of micro/nanospheres in an artificial saliva medium. The menthol/PLGA micro/nanospheres thus obtained had a size distribution of between 217 nm and 13 µm and particles with spherical and dense morphology were evidenced by SEM micrographs. FTIR and TGA data showed an increase up to 60% of menthol incorporated in the micro/nanoparticles. The degradation of menthol-loaded PLGA micro/nanoparticles in artificial saliva significantly affected the particles morphology and appears to be an effective medium for releasing menthol.

The development of polyester based materials with enhanced properties as well as the use of post- consumer plastics as raw material has been an increasing market demand. This work aims the synthesis and characterization of aromatic polyesters/titanium dioxide nanocomposites from PET and using TiO2 (0, 1, 3 and 5% w/w) as filler by in situ polymerization. The results obtained by DSC, XRD and FTIR analyzes evidenced an interaction between the OH groups on the TiO2 surface with the ester groups of the polymer leading to decrease of the polymer crystallinity and of hydrophilicity. By SEM images was possible to note a homogeneous distribution of the filler into polymer matrix with 1%w/w TiO2 (average particle size of 199 nm), however for larger amounts of filler (3 and 5% TiO2) revealed the aggregates formation. The results showed an improvement of thermal properties and hardness of the nanocomposites containing TiO2 nanoparticles compared to pristine polyester.

Embora tecnologias de captura e armazenamento de carbono (CCS) estejam recebendo grande atenção para a mitigação do efeito estufa, ainda existem muitas desvantagens, tais como o aumento dos custos e gastos de energia associados à sua implementação. No entanto, o uso de CO2 como bloco de construção C1 em síntese orgânica pode ser muito atraente para o desenho de processos ecológicos. Neste trabalho, foram estudados a sorção de CO2 e atividades catalíticas de alguns líquidos iônicos (ILs) base imidazólio para síntese de carbonato cíclico. O trabalho demonstra que a presença de um grupo nucleófilo no sistema catalítico pode melhorar seu desempenho, através da utilização de um IL com ânion halogenado ou por mistura de co-catalisador halogenado com ILs. A última abordagem permitiu a obtenção de um sistema de captura de CO2 eficaz, constituída por IL fluorado mais ZnBr2 que realiza a síntese de carbonato cíclico com 90% de rendimento e 82% de seletividade.

Although the carbon capture and storage (CCS) technologies are receiving great attention for mitigation of greenhouse gas effect, the increasing costs and energy penalties associated to its implementation are still major drawbacks. However, the use of CO2 as a C1 building block in organic synthesis can be very attractive for the design of environmentally friendly processes. In this work, we have studied both the CO2 sorption and catalytic activities of some imidazolium based ionic liquids (ILs) for cyclic carbonate synthesis. The work demonstrates that the presence of a nucleophilic group in the catalytic system can enhance its performance by the use of an IL with a halide anion or by mixing a halide co-catalyst with ILs. The latter approach allowed to obtain an effective system for CO2 capture constituted by a fluorinated IL plus ZnBr2 that performs cyclic carbonate synthesis with 90% yield and 82% of selectivity.

Rising anthropogenic CO2 emissions are considered a major contributor to the greenhouse effect. There are several options for reducing atmospheric CO2 levels, and among these alternatives, Carbon Capture and Storage (CCS) has been identified as an effective and promising approach. This work investigated the feasibility of using serpentinite as a vehicle for carbon storage presenting a source-sink match. The main results of the work confirmed that serpentinite is appropriate for the carbonation process due to the high concentration of Mg in its composition.

Nas últimas décadas têm sido desenvolvidos novos materiais sintéticos que possuam biofuncionalidade e biocompatibilidade para que se tornem um biomaterial. Polímeros bioestáveis têm uso generalizado no campo biomédico, sendo que muitos avanços em biomateriais poliméricos têm ocorrido na busca de melhorias aos implantes cardiovasculares. Atualmente, os materiais sintéticos mais utilizados para a fabricação de próteses vasculares são o PET e o PTFE devido a sua estabilidade química após o implante. Neste trabalho é apresentado um estudo das propriedades térmicas e mecânicas de dispositivos comerciais à base de PET e PTFE, bem como sua citotoxicidade em células de fibroblastos de camundongos, 3T3-NIH, através de testes para a avaliação da viabilidade celular (teste VN e MTT). Estes materiais apresentaram grande estabilidade térmica (acima de 300 ºC), mesmo após 270 dias de degradação in vitro e um comportamento elástico (deformação máxima de 186±22% para o PET e de 65±19% para o PTFE). A viabilidade celular por VN e MTT do dispositivo de PTFE foi superior a 80%, permitindo classificar o mesmo como não citotóxico. No teste de VN, o dispositivo de PET não apresentou efeito citotóxico, contudo os resultados por MTT indicaram que o mesmo causa alteração da funcionalidade mitocondrial, independente da dose e tempo avaliados.

In recent decades new synthetic materials have been developed with adequate biofunctionality and biocompatibility to become a biomaterial. Biostable polymers have widespread use in the biomedical field, and many advances in polymeric biomaterials have been made in the search for improvements to cardiovascular implants. Currently, the most commonly used synthetic materials for the production of vascular grafts are PTFE and PET, due to their chemical stability after implant. In this work, a study of the thermal and mechanical properties of the commercial devices based on PET and PTFE is reported, as well as their cytotoxicity in mouse fibroblast cells, 3T3- NIH, through tests for the evaluation of cell viability (MTT test and VN). These materials showed high thermal stability (over 300 ° C), even after 270 days in vitro degradation and elastic behavior (maximal strain value of 186±22% by PET and 65±19% by PTFE). Cell viability by VN and MTT of PTFE device was more than 80%, thus, classified as non-cytotoxic. For PET device, VN test showed no cytotoxic effect, however the results obtained by MTT indicated that it causes alteration of mitochondrial function, independent of dose and time measured.

Optically transparent membranes from bacterial cellulose (BC)/polycaprolactone (PCL) have been prepared by impregnation of PCL acetone solution into dried BC membranes. UV-Vis measurements showed an increase on transparency in BC/PCL membrane when compared with pristine BC. The good transparency of the BC/PCL can be related to the presence of BC nanofibers associated with deposit of PCL nano-sized spherulites which are smaller than the wavelength of visible light and practically free of light scattering. XRD results show that cellulose type I structure is preserved inside the BC/PCL membrane, while the mechanical properties suggested indicated that PCL acts as a plasticizer for the BC membrane. The novel BC/PCL membrane could be used for preparation of fully biocompatible flexible display and biodegradable food packaging.

Due to their versatility, polyurethane (PU) foams have many different applications, such as sponges, filling materials in furniture, automotive seats and clothes, among others. It is also one of the main refrigerator components serving as a heat insulating material. As PUs find different application niches, they must be largely produced and, consequently, lots of waste are generated. In this work we intend to contribute to the recycle of this waste. The recovery of polyol from flexible polyurethane foams was carried out using the glycolysis process and testing different catalysts. Grounded polyurethane and a solvent, diethyleneglycol (DEG), were kept at 200 ºC and under nitrogen atmosphere during three hours in the presence of a catalyst. All catalysts tested promoted the polyol mixture formation, with Zinc acetate producing the best depolymerization rate. The catalysts efficiency for the depolymerization reaction follows the order: DBTDL< BTO< HBTO< DEA ≈ Ba(Ac)2< MEA ≈ KAc< Zn(Ac)2.