O objetivo deste estudo foi avaliar, in vitro, o comportamento citotóxico e a produção de citocinas induzidos pelos materiais restauradores resinosos contendo novos monômeros KaloreTM (GC FUJI) e FiltekTMSilorane (3M ESPE) em comparação com as resinas compostas convencionais Charisma® (Heraeus-Kulzer) e FiltekTM Z250 (3M ESPE), em cultura de fibroblastos L929 e macrófagos RAW 264.7 de camundongos. As células foram estimuladas com as resinas compostas, fotopolimerizadas ou não, a partir da colocação em contato indireto ou pela extração de seus componentes durante 15, 45 e 120 dias. Após a incubação por 6, 12 e 24 horas, a viabilidade celular foi avaliada pelo Ensaio MTT e a produção de citocinas foi investigada pelo ensaio imunoenzimático (ELISA). Os dados obtidos foram analisados utilizando-se análise de variância de uma via (One-way ANOVA) e pós-teste de Tukey (α=0,05). A produção de TNF-α e IL-6 não foi detectada em fibroblastos da linhagem L929, após 6, 12 e 24 horas de contato indireto com as resinas compostas KaloreTM e FiltekTM Silorane. Por outro lado, a produção de TNF-α foi detectada em macrófagos da linhagem RAW 264.7, mas não foi influenciada pelo contato indireto com as resinas compostas, com exceção da resina FiltekTM Silorane que inibiu a produção de TNF-α, após 12 horas de incubação. Os extratos obtidos das resinas compostas KaloreTM e FiltekTM Silorane incubadas por 15 dias, se mostraram mais citotóxicos do que os extratos incubados por 45 e 120 dias. A citotoxicidade da resina composta KaloreTMnão foi influenciada pela fotopolimerização enquanto a citotoxicidade da resina FiltekTM Silorane foi maior no grupo não fotopolimerizado. Os extratos das resinas compostas Charisma® e FiltekTM Z250, obtidos aos 15, 45 e 120 dias de incubação, não foram citotóxicos 24 horas após a estimulação das células. Ainda, a resina FiltekTM Silorane, fotopolimerizada ou não, estimulou a produção de IL-6 no período de 45 dias de extração. A resina KaloreTM, diferentemente da resina FiltekTM Silorane, estimulou a produção de IL-10, aos 15 dias de extração. Entretanto, no período de 45 de extração, a resina KaloreTM fotopolimerizada inibiu a produção de IL-10, após 12 horas de incubação, e aos 120 dias de extração não houve produção detectável de IL-10 em nenhum dos grupos avaliados. / The aim of this study was to evaluate in vitro the cytotoxicity and the production of cytokines induced by resin-based restorative materials containing new monomers KaloreTM (GC FUJI) and FiltekTM Silorane (3M ESPE) compared with conventional composite resins Charisma® (Heraeus-Kulzer) and FiltekTM Z250 (3M ESPE), in mice L929 fibroblast and RAW 264.7 macrophages culture. Cells were stimulated with the composite resins, light-cured or not, by indirect contact or extraction during 15, 45, and 120 days. After incubation for 6, 12, and 24 hours, cell viability was assessed by MTT assay and production of cytokines was investigated by enzyme-linked immunosorbent assay (ELISA). Data obtained were analyzed using oneway analysis of variance (ANOVA) and Tukey post-test ( α = 0.05). Production of TNF-α and IL-6 was not detected in L929 fibroblasts either 6, 12 or 24 hours following indirect contact with the KaloreTM and FiltekTM Silorane composite resins. On the other hand, the production of TNF-α was detected in RAW 264.7 macrophages, but was not influenced by indirect contact with composite resins, with the exception of the FiltekTM Silorane resin that inhibited the production of TNF-α, after 12 hours of incubation. The extracts obtained from incubation for 15 days with composite resins KaloreTM and FiltekTM Silorane were more cytotoxic than extracts incubated for 45 and 120 days. Cytotoxicity of composite KaloreTM was not influenced by light curing while cytotoxicity of FiltekTM Silorane resin was higher in the group that not received light-cure. Extracts of Charisma® and FiltekTM Z250 composite resins, obtained at 15, 45, and 120 days of incubation, were not cytotoxic 24 hours after stimulation of the cells. Also, FiltekTM Silorane, light-cured or not, stimulated the production of IL-6 following 45 days of incubation. KaloreTM resin extract for 15 days, unlike FiltekTM Silorane resin, stimulated the production of IL-10. However, during periods of 45 days of extraction, KaloreTM resin, light-cured, inhibited the production of IL-10, after 12 hours of incubation, and 120 days of extraction there was no detectable production of IL-10 in any of the groups.

Orientador: Oswaldo Luiz Alves / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-19T10:57:30Z (GMT). No. of bitstreams: 1 Rodrigues_CarolinaMartins_D.pdf: 3785624 bytes, checksum: 900b631cfaf12d5446ec0fee86c6118b (MD5) Previous issue date: 2011 / Resumo: Esta Tese visa avaliar a importância da morfologia e da composição química das nanoestruturas de titanato usando a modificação com moléculas orgânicas e desenvolvimento de nanocompósitos poliméricos. As nanoestruturas de titanato de sódio foram obtidas via tratamento hidrotérmico em solução de hidróxido de sódio 10 mol L em 150 e 180°C. De acordo com as caracterizações físico-químicas foi observada a formação de nanotubos de titanato de sódio quando o tratamento hidrotérmico foi realizado a 150°C. No caso do tratamento feito a 180°C foi verificada a formação de nanofitas de titanato de sódio. Os nanotubos de titanato protonados foram obtidos via processo de troca iônica dos nanotubos de titanato de sódio em solução de ácido clorídrico 0,1 mol L. Uma vez obtidas às nanoestruturas de titanato, estas foram submetidas à etapa de modificação com moléculas orgânicas. Essa etapa de modificação consistiu na dispersão destas nanoestruturas em soluções de ácido oléico (OAC) e de brometo de cetiltrimetilamônio (CTAB). Nesta etapa foi verificado que os nanotubos apresentaram maior adsorção/ligação das moléculas orgânicas, o que pode ser relacionado à sua maior área superficial. Em relação à composição química foi observado que os nanotubos de titanato de sódio adsorveram/ligaram maior quantidade de CTAB, o que pode ser indicativo da maior quantidade de grupos OH presentes na superfície dos nanotubos de titanato de sódio, o que poderia resultar em um potencial zeta mais negativo, gerando uma maior interação eletrostática entre os nanotubos e o CTAB. Por último, as nanoestruturas de titanato foram incorporadas em filmes de poli (metacrilato de metila) (PMMA) e borracha natural pelo método de evaporação de solvente. Para o caso do PMMA, as nanofitas resultaram em maior estabilidade termo-oxidativa, e os nanotubos protonados resultaram em melhores propriedades mecânicas. Em ambos os casos, as nanoestruturas foram observadas na forma de aglomerados na matriz. O uso de nanoestruturas modificadas nos filmes de PMMA resultou em melhor dispersão e também na melhoria das propriedades mecânicas. Para os nanocompósitos de borracha, os nanotubos de titanato de sódio foram os que apresentaram melhor dispersão e aumento discreto nas propriedades mecânicas / Abstract: The aim of this thesis was to evaluate the importance of the morphology and chemical composition of titanate nanostructures using the modification with organic molecules and the development of polymeric nanocomposite. The sodium titanate nanostructures were obtained via hydrothermal treatment in a solution of 10 mol L sodium hydroxide at 150 and 180°C. According to the physical-chemical characterizations, it was observed the formation of sodium titanate nanotubes when the hydrothermal treatment was performed at 150°C. In the case of treatment given to 180°C, the formation of sodium titanate nanoribbons was observed. Protonated titanate nanotubes were obtained by ion exchange process of sodium titanate nanotubes in 0.1 mol L hydrochloric acid solution. Once obtained the titanate nanostructures, they were subjected to phase modification with organic molecules. This step of modification was performed dispersing the nanostructures in solutions of oleic acid (OAC) and cetyltrimethylammonium bromide (CTAB). At this stage it was found that the nanotubes had a higher adsorption/bonding of organic molecules, which may be related to their larger surface area. Regarding the chemical composition, it was observed that the sodium titanate nanotubes adsorbed/bonding contain the highest amount of CTAB, which can be related to the greater amount of OH groups adsorbed on the surface of sodium titanate nanotubes, which could result in a more negative zeta potential, producing a greater electrostatic interaction between the nanotubes and CTAB. Finally, the titanate nanostructures were embedded in films of poly (methyl methacrylate) (PMMA) and also films of natural rubber by the casting method. For the case of PMMA, the nanoribbons resulted in a greater thermo-oxidative stability, and protonated nanotubes resulted in better mechanical properties. In both cases, the nanostructures were observed in the form of clusters in the matrix. The modified nanostructures embedded in the film of PMMA dispersed better and the mechanical properties were improved. For the rubber nanocomposites, the sodium titanate nanotubes showed greater dispersion and resulted in a slight increase in mechanical properties / Doutorado / Quimica Inorganica / Doutor em Ciências

Orientadores: Ana Maria Frattini Fileti, João Alexandre Ferreira da Rocha Pereira / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Resumo: Não Informado / Made available in DSpace on 2018-08-04T07:25:30Z (GMT). No. of bitstreams: 1 Antunes_ArnaldoJoseBannwart_D.pdf: 3655663 bytes, checksum: adb0d2c9c8215b5c4205125f25e9342c (MD5) Previous issue date: 2005 / Abstract: The present work is concerned with the design and experimental testing of control system with a fuzzy algorithm for temperature control of a methyl methacrylate (MMA) batch polymerization. Ethyl acetate is used as solvent and benzoyl peroxide is the reaction initiator. According to the literature, this reaction is complex and highly nonlinear, therefore there is some dificulty choosing the most appropriate controller. To verify the system complexity and the influence of the fuzzy control algorithm it is compared to a conventional PID (velocity form) controller. The controller tuning parameters were obtained via open-Ioop experiments. For the conventional PID, the Cohen-Coon method was applied followed by stability analysis. For the fuzzy controller, the open loop results helped to shape the knowledge base, with the determination of the membership functions. This work shows the several alternatives for tuning a fuzzy controller. It can be achieved by modifying the knowledge base or scaling factors. Besides, a digital temperature filter was succesfully used in order to prevent the oscillatory behaviour of the reaction temperature. According to experimental results, the PID-fuzzy was considered more suitable and reliable for this polymerization process control since it outperformed PID velocity form algorithm / Doutorado / Sistemas de Processos Quimicos e Informatica / Doutor em Engenharia Química

No description available.

Orientador: Alexandre Luiz Souto [Unesp] Borges / Resumo: Este estudo visou sintetizar e caracterizar mantas não tecidas de nanofibras (NFs) do acrilonitrila butadieno estireno (ABS), poliamida 6 (PA6) e poliestireno (PS), e avaliar sua capacidade de ser utilizada como reforço no polimetilmetacrilato (PMMA). O ABS foi dissolvido em diclorometano e acetona, a PA6 pelo 1,1,1,3,3,3-hexafluoro-2-propanol e o PS pela dimetilformamida, em uma concentração definida em estudo piloto. Após determinados os melhores parâmetros de eletrofiação (tensão contínua, razão de fluxo e distância agulha/anteparo) as amostras de cada grupo foram analisadas em microscopia eletrônica de varredura, análise de molhabilidade, análise de difratometria de raios X, espectroscopia de infravermelho por transformada de Fourier, diâmetro das fibras e resistência a tração. As NFs produzidas foram incluídas na área de tração dos corpos de prova em resina acrílica ativada termicamente (RAAT) conforme ISO1567, perfazendo 4 grupos (n=20), 1 controle (Grupo 1) e 3 experimentais (Grupo 2, RAAT+NF/ABS; Grupo 2, RAAT+NF/PA6; Grupo 4, RAAT+NF/PS), para ensaio de flexão três pontos para analisar suas propriedades mecânicas, como: módulos de elasticidade e resistência a flexão. De acordo com os testes de caracterização, as mantas se apresentaram hidrofóbicas, não houve mudança de sua estrutura polimérica, concluindo-se então que a técnica da eletrofiação foi promissora na síntese de mantas de NFs. A variação dos parâmetros afetou diretamente a morfologia, resultando em fibras u... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study aimed to synthesize and characterize non-woven blankets of acrylonitrile butadiene styrene (ABS), polyamide 6 (PA6) and polystyrene (PS) nanofibers (NFs), and to evaluate their ability to be used as reinforcement in polymethyl methacrylate (PMMA). ABS was dissolved in dichloromethane and acetone, PA6 by 1,1,1,3,3,3- hexafluoro-2-propanol and PS by dimethylformamide at a concentration defined in a pilot study. After determining the best electrospun parameters (continuous voltage, flow rate and needle/shield distance) the samples from each group were analyzed by scanning electron microscopy, wettability analysis, X-ray diffraction analysis, Fourier transform infrared spectroscopy, fiber diameter and tensile strength. The NFs produced were included in the tensile area of the thermally activated acrylic resin (RAAT) specimens according to ISO1567, making up 4 groups (n = 20), 1 control (Group 1) and 3 experimental (Group 2, RAAT+NF/ABS; Group 3, RAAT+NF/PA6 and Group 4 (RAAT+NF/PS), for three point bending test to analyze their mechanical properties, as: modules of elasticity and flexural strength. According to the characterization tests, the blankets were hydrophobic, there was no change in their polymeric structure, concluding that the electrospinning technique was promising in the synthesis of NFs blankets. The parameters variation affected directly in the morphology, resulting in uniform, bulky and without defects (beads) NFs blankets. The Groups 3 and 4 (NF/PA6+RA... (Complete abstract click electronic access below) / Mestre

Asymmetric polymeric materials can be formed by either top-down or bottom-up methods. Bottom-up methods involve assembling the atoms and molecules to form small nanostructures by carefully controlled synthesis, which results in a reduction of some of the top-down limitations. In this dissertation, thermal, tribological and antireflective properties of polymeric materials have been enhanced by introducing structural asymmetry. The overall performance of commercial polymeric coatings, e.g. epoxy and polyvinyl chloride, has been improved by conducting the blending methods, specifically, chemical modification (α,ω-dihydroxydimethyl(methyl-vinyl)oligoorganosiloxane), cross-linking (triallyl isocyanurate), and antioxidant (tris(nonylphenyl) phosphite) incorporation. The nonequilibrium polymeric structures (moth-eye and square array) have been developed for the ultrahigh molecular weight block copolymers via the short-term solvent vapor annealing self-assembly. The large domain size of the moth eye structure allows for improvement of the light transmittance particularly in the visible and near infrared ranges, while the square arrangement of the block copolymer opens the possibility of magnetic data storage application by the large magnetic nanoparticles' embedment or masking of the superconductors.

No description available.

Indiana University-Purdue University Indianapolis (IUPUI) / Recent theoretical and experimental studies, suggest that Carbon nanotubes are 10-100 times higher than the strongest steel at a fraction of the weight. There are two main types of CNTs that can have high structural perfection. Single-walled nanotubes (SWNTs) consist of a single graphite sheet seamlessly wrapped into a cylindrical tube. Multi-walled carbon nanotubes (MWNTs) comprise an array of such nanotubes concentrically nested like rings of a tree trunk. Denture base acrylics have been reinforced with different materials with limited success. No single reinforced material has showed a great statistical difference in mechanical improvement. The goal of this investigation was to study the effects of Single Walled Carbon Nanotubes reinforcement on the mechanical properties of commercially available denture base PMMA. Denture Base material was reinforced with Single-walled Carbon Nanotubes (SWNTs) at dispersion of 0.25 wt % (group 1), 0.50 wt % (group 2), 0.75 wt % (group 3) and 0.0 wt % (group 4, control). Samples from each group were evaluated for microhardness, flexural strength, flexural modulus, and fracture toughness. The samples were tested in two conditions, as manufactured (dry) and after storing at 37 C for 7 days (wet). Data from four experiments was analyzed by ANOVA. All control sample values were in the range of acceptance compared with previous studies. Higher values were obtained for the control groups for flexural strength and modulus compared with the experimental samples. (p < 0.05) There was no statistical difference regarding fracture toughness between control and experimental groups. A statistical difference was observed in Hardness. The experimental group showed higher values under compression.

Degradable low-fouling hydrogels are ideal vehicles for drug and cell delivery. For each application, hydrogel degradation rate must be re-optimized for maximum therapeutic benefit. We developed a method to rapidly tune degradation rates of low-fouling poly(oligo(ethylene glycol) methyl ether methacrylate) (P(EG)xMA) hydrogels by modifying two interdependent variables: (1) base-catalyzed crosslink degradation kinetics, dependent on crosslinker electronics (electron withdrawing groups (EWGs)); and (2) polymer hydration, dependent on the molecular weight (MW) of poly(ethylene glycol) (PEG) pendant groups. By controlling EWG strength and PEG pendant group MW, P(EG)xMA hydrogels were tuned to degrade over 6 to 52 d. A six-member P(EG)xMA copolymer library yielded slow and fast degrading low-fouling hydrogels for short- and long-term delivery applications. The degradation mechanism was also applied to RGD-functionalized poly(carboxybetaine methacrylamide) (PCBMAA) hydrogels to achieve slow (52 d) and fast (13 d) degrading low-fouling, bioactive hydrogels. / Thesis / Master of Science (MSc) / The delivery of drugs and cells to disease sites is hindered by transport barriers, which can be overcome through local delivery. Injectable hydrogels can serve as local depots that release drugs or cells to improve therapeutic benefit. Currently, however, hydrogels suffer from uncontrolled degradation in the body, degrading at unpredictable rates dependent on the local environment; hydrogels with predictable and tunable degradation rates are therefore required. Herein, we report a method to produce a library of polymers that in situ crosslink to form hydrogels with a range of degradation rates only influenced by the local environments pH, a known quantity. Moreover, the polymers are low-fouling and therefore have minimal non-specific interactions with biomolecules and cells, which improves biocompatibility.

This thesis is an experimental investigation of the phase behavior, volumetric properties, and viscosity of poly (methyl methacrylate) (PMMA), poly (ε-caprolactone) (PCL) and their blends. Homopolymerization and copolymerizations of methyl methacrylate (MMA) and 2-methylene-1,3-dioxepane (MDO) in mixtures of acetone + CO2 have also been explored. The viscosities and densities of acetone + CO2 mixtures were measured in the temperature range 323-398 K at pressures up to 35 MPa. This is the first study in which viscosity of acetone + CO2 mixtures have been measured and the mixtures have been evaluated as solvents for PCL. It is shown that PCL can be readily dissolved in these fluid mixtures at modest pressures even at high carbon dioxide levels. Investigations have been conducted over a temperature range from 323 to 398 K at pressures up to 50 MPa for polymer concentrations up to 20 wt %, and CO2 concentrations up to 60 wt %. It is shown that in these mixtures PCL is dissolved at pressures that are much lower than the pressures reported for miscibility in the mixtures of carbon dioxide with other organic solvents. It is shown that PMMA also readily dissolves at modest pressures. Blends of PMMA and PCL require higher pressures than for the individual polymers for complete miscibility. Free-radical polymerizations of MMA in acetone at 343 K were followed using in-situ measurements of viscosity and density at different pressures from 7- 42 MPa. This is the first time viscosity has been used as a real-time probe of high pressure polymerizations. Two distinct kinetic regimes were identified. Homopolymerizations of MDO were conducted in carbon dioxide at 323 and 343 K at pressures up to 42 MPa. For the first time it is shown that high molecular weight PCL can be produced from MDO in high pressure CO2. Ring-opening free-radical copolymerizations of MDO with MMA, styrene and acrylonitrile were conducted for the first time in carbon dioxide and have been shown to lead to polymers with high molecular weights. / Ph. D.