Estudo morfológico da blenda polimérica poli(metacrilato de metila)/poli(tereftalato de etileno) reciclado (PMMA/PET)

Among the options for plastics modification more convenient, both from a technical-scientific and economic, is the development of polymer blends by processing in the molten state. This work was divide into two stages, with the aim to study the phase morphology of binary blend PMMA / PET blend and this compatibilized by the addition of the poly(methyl methacrylate-co-glycidyl methacrylate-co-ethyl acrylate) copolymer (MMA-GMA-EA). In the first stage is analyzed the morphology of the blend at a preliminary stage where we used the bottle-grade PET in a Haake torque rheometer and the effect of compatibilizer in this blend was evaluated. In the second stage the blend was processed using the recycled PET in a single screw extruder and subsequently injection molding in the shape of specimens for mechanical tests. In both stages we used a transmission electron microscopy (TEM) to observe the morphologies of the samples and an image analyzer to characterize them. In the second stage, as well as analysis by TEM, tensile test, scanning electron microscopy (SEM) and atomic force microscopy (AFM) was performed to correlate the morphology with the mechanical properties. The samples used in morphological analyzes were sliced by cryo-ultramicrotomy technique for the analysis by TEM and the analysis by SEM and AFM, we used the flat face of the block after cut cryogenic. It was found that the size of the dispersed phase decreased with the addition of MMA-GMA-EA in blends prepared in a Haake. In the tensile test, the values of maximum tensile strength and modulus of elasticity is maintained in a range between the value of pure PMMA the pure PET, while the elongation at break was influenced by the composition by weight of the PMMA mixture. The coupling agent corroborated the results presented in the blend PMMA / PETrec / MMA-GMA-EA (80/15/5 %w/w), obtained by TEM, AFM and SEM. It was concluded that the techniques used had a good morphologic correlation, and can be confirmed for final analysis of the morphological characteristics of the blends PMMA / PET

Influência de tratamentos térmicos no comportamento mecânico da blenda poli(metacrilato de metila) / poli(tereftalato de etileno) reciclado

Studies indicate that a variation in the degree of crystallinity of the components of a polymer blend influences the mechanical properties. This variation can be obtained by subjecting the blend to heat treatments that lead to changes in the spherulitic structure. The aim of this work is to analyze the influence of different heat treatments on the variation of the degree of crystallinity and to establish a relationship between this variation and the mechanical behavior of poly(methyl methacrylate)/poly(ethylene terephthalate) recycled (PMMA / PETrec) with and without the use of compatibilizer agent poly(methyl methacrylate-al-glycidyl methacrylate-al-ethyl acrylate) (MMAGMA- EA). All compositions were subjected to two heat treatments. T1 heat treatment the samples were treated at 130 ° C for 30 minutes and cooled in air. In T2, the samples were treated at 230 ° C for 5 minutes and cooled to approximately -10 ° C. The variation of the degree of crystallinity was determined by the proportional relationship between crystallinity and density, with the density measured by pycnometry. The mechanical behavior was verified by tensile tests with and without the presence of notches and pre-cracks, and by method of fracture toughness in plane strain (KIC). We used the scanning electron microscopy (SEM) to analyze the fracture surface of the samples. The compositions subjected to heat treatment T1, in general, showed an increase in the degree of crystallinity in tensile strength and a tendency to decrease in toughness, while compositions undergoing treatment T2 showed that the opposite behavior. Therefore, this work showed that heat treatment can give a polymer blend further diversity of its properties, this being caused by changes in the crystal structure

Processamento e caracterização da blenda poli (metacrilato de metila) (PMMA) elastomerico e poli (tereftalato de etileno) (PET) pós-consumo

This work studied the immiscible blend of elastomeric poly(methyl methacrylate) (PMMA) with poly(ethylene terephthalate) (PET) bottle grade with and without the use of compatibilizer agent, poly(methyl methacrylate-co-glycidyl methacrylate - co-ethyl acrylate) (MGE). The characterizations of torque rheometry, melt flow index measurement (MFI), measuring the density and the degree of cristallinity by pycnometry, tensile testing, method of work essential fracture (EWF), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were performed in pure polymer and blends PMMA/PET. The rheological results showed evidence of signs of chemical reaction between the epoxy group MGE with the end groups of the PET chains and also to the elastomeric phase of PMMA. The increase in the concentration of PET reduced torque and adding MGE increased the torque of the blend of PMMA/PET. The results of the MFI also show that elastomeric PMMA showed lower flow and thus higher viscosity than PET. In the results of picnometry observed that increasing the percentage of PET resulted in an increase in density and degree crystallinity of the blends PMMA/PET. The tensile test showed that increasing the percentage of PET resulted in an increase in ultimate strength and elastic modulus and decrease in elongation at break. However, in the phase inversion, where the blend showed evidence of a co-continuous morphology and also, with 30% PET dispersed phase and compatibilized with 5% MGE, there were significant results elongation at break compared to elastomeric PMMA. The applicability of the method of essential work of fracture was shown to be possible for most formulations. And it was observed that with increasing elastomeric PMMA in the formulations of the blends there was an improvement in specific amounts of essential work of fracture (We) and a decrease in the values of specific non-essential work of fracture (βWp)

Obtenção de antioxidante a partir de derivados do LCC

Cashew-nut-shell-liquid (CNSL) is a phenolic oil that hás been due its their antioxirsion properties for use in fuels. The present work develops a method to the conversion of hidrogenated cardanol, that is the main component of the CNSL, in a compound with similar chacteristics to antioxidants used in products from petroleum. The antioxidants wasd obtained by exhaustive alkylation of the compound with tert-butyl chloride. After completing the optimization of several reaction steps, the product 2,4,6 tri-tert-butyl (pentadecylphenol) was obtained for the first tima. Characteeization and determination of physico-chemical properties were realized too, as well as wasd developed a study for check your application as an oxidative inhibitor by the molecular modeling. Estimation of process evalution was executed as well, where a rapid and practical computational methodology was utilizated in projects of the fine chemistry. The research showed satisfactory results and it could be concluded that the commercialization of this chemical products is feasible

Volatile compounds from organic and conventional passion fruit (Passiflora edulis F. Flavicarpa) pulp

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Caracterização de látices acrílicos em função da neutralização de seus grupos carboxilas

Latexes based on acrylic acid, acrylamide, ethyl methacrylate, and ethyl acrylate were synthesized via emulsion polymerization with different monomer compositions. The resultant latices were thickened with different molar ratios of NaOH to acrylic acid and were analyzed in terms of acid‐basis titrimetry, turbidimetry, rheology, and tensiometry. Titrimetry, turbidimetry, and rheometry were used to analyze factors such as carboxyl group availability and particle solubilization, tensiometry monitoring the influence of carboxyl neutralization on polymer‐surfactant interactions. For the acrylic acid content used in this work (20 wt%), the results indicated that as carboxyl groups distribution became more homogeneous, the process of latex thickening became more effective

Caracterização de poliacrilamida parcialmente hidrolisada em regime concentrado

A partially hydrolyzed polyacrylamide (HPAM) is a copolymer composed of acrylamide and sodium acrylate. Due to its wide range of applications there are different methods for its quantification and characterization in solution systems. Evaluation of C* is important to describe the transition from dilute to semi-dilute, behavior, when the solution will have its characteristic viscosity at concentrations above C*. This dissertation describes the determination of the critical concentration of overlap C* by potentiometry of partially hydrolyzed polyacrylamide - HPAM under acidic conditions. Based on the law of mass action and the proper treatment of the constant of aggregate formation, polymer molecular weight, degree of polymerization and hydrolysis were calculated. The inflection point was determined by the intersection of the resulting equation and mathematical development, statistically satisfy the experimental points relating the number of moles of monomers (n), equilibrium constant of formation of the entanglements (K*), pH, C* and acidity constant of the polymer (Ka). The viscometric parameters of C* showed a percentage difference compared to potentiometers. The results for the determination of C*, and degree of copolymerization molar mass proved to be a simple alternative for the characterization of polymers with protonated monomers and water soluble

Catálise estereoespecífica de estireno por titanocenos alquil-substituídos do tipo (RCp)2TiCl2

Uma série de sete complexos alquil substituídos do tipo (RCp)2TiCl2 (R= H, etila, n-propila, iso-propila, n-butila, iso-amila, ciclo-hexila) foi preparada juntamente com o ainda inédito contendo R= sec-butila, e o efeito do substituinte na polimerização do estireno foi investigada à temperaturas de polimerização de 0 e 50 ºC. Foi encontrado que R = n-butila maximiza a produção de poliestireno sindiotático. Ligantes alquilas com R = RCH2- são superiores aos R = RR CH- e ao precursor Cp2TiCl2 na produção de poliestireno sindiotático de alto peso molecular.

Efeitos estéricos e eletrônicos de substituintes alquilas em catalisadores titanocênicos solúveis na polimerização sindioespecífica de estireno

Titanocenos são catalisadores solúveis conhecidos para a polimerisação estereoespecífica de olefinas pró-quirais como o estireno. Nesse trabalho descrevemos as relações entre as características do poliestireno e a estrutura do precursor do catalisador, de fato aqueles da família (RCp)2TiCl2 (R = H, etila, iso-propila, n-propila, sec-butila, n-butila, iso-amila e ciclohexila). Todos os catalisadores são ativos para a produção de poliestireno acima de zero graus centígrados. A sindiotaticidade dos polímeros são dependentes da cadeia lateral dos anéis aromáticos do titanoceno e da temperatura da polimerização. A relação entre os fatores estéricos e eletrônicos do precursor do catalisador e os produtos de polimerização são apresentados e discutidos.

Caracterização do perfil da ação do ácido gálico e seus derivados sobre processos oxidativos in vitro e ex vivo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo da estabilidade química, física e liberação in vitro da eritromicina veiculada em sistemas líquido-cristalinos para tratamento da Acne Vulgaris

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ácido cafeico e seus ésteres: inibição do burst oxidativo de neutrófilos e efeito anti-Helicobacter pylori

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Bioprospecção de produtos naturais e sintéticos em modelos celulares de citotoxicidade, genotoxicidade, apoptose e quimioprevenção do câncer

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Análise combinada dos efeitos dos revestimentos nas propriedades de fibras ópticas comerciais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Materiais fotocrômicros de matriz polimérica e respectivos método de obtenção e uso

A presente invenção refere-se a um material compásito, de matriz polimérica, no qual são incorporados materiais fotossensiveis, notadamente heteropoliánions (polioxometalatos POMs), partícularmente ácido fosfotúngstico, ácido siíícotúngstico, ácido fosfomolíbdico e ácido silicomofíbdico, A matriz polimérica é constituída preferencialmente por acrilato, metacrilato, acetato de celulose e hidroxipropilcelulose. Refere-se também ao processo para incorporação dos agentes fotossensíveis nas matrizes políméricas e ao uso do dito produto obtido ao final do processo.