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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

S?ntese e caracteriza??o de poliuretanos bioest?veis com potencial aplica??o na ?rea cardiovascular

Cabral, Emanuelli Louren?o 25 January 2012 (has links)
Made available in DSpace on 2015-04-14T13:58:46Z (GMT). No. of bitstreams: 1 436434.pdf: 2324920 bytes, checksum: cdf79816569d7d9b352a5a2d9b93437f (MD5) Previous issue date: 2012-01-25 / The search for materials that can replace or restore damaged tissues is due to the search for better life quality of the population. Considering that cardiovascular diseases are the main causes of death in Brazil (Banco de Sa?de, 2010), needs some devices that have efficacy in cardiac regeneration, addressing about issues of long-term safety and promoting the healing of vascular vessels (PR Newswire, 2010). In this sense, this paper developed the synthesis of biostable polyurethanes from the reaction of polycaprolactone diol (PCL) with different diisocyanates (HDI and H12MDI), characterizing them by morphological analysis (MEV), thermal (TGA and DSC), mechanical (DMA) and structural (IV), but also evaluating their in vitro cytotoxicity, by testing for the evaluation of cell viability (MTT and VN test) and cell proliferation (Trypan Blue test) using NIH-3T3 fibroblast cells, comparing them with commercial materials, Dacron and PTFE. The obtained results showed that the synthesized polyurethanes had average molar weight (Mw) ranging between 30000 and 263000 g/mol, as well as a plasticity depended of polyol used. The mechanical behavior of polyurethanes showed similar or greater than the commercial material, Dacron and PTFE. The biostability tests showed that there was mass loss below 20% of the materials exposed to hydrolytic degradation in the period of 270 days and below 5% in the enzymatic degradation in the period of 30 days. The cell viability of polyurethanes was superior to 80%, considered non-cytotoxic. Polyurethanes in this study showed favorable results for its possible use as biomaterial in cardiac applications / A procura por materiais que possam substituir ou restaurar tecidos danificados deve-se ? busca por melhor qualidade de vida da popula??o. Levando em considera??o que doen?as cardiovasculares s?o as principais causas de mortes no Brasil (Banco de Sa?de, 2010), necessita-se de dispositivos que possuam efic?cia na regenera??o card?aca, abordando quest?es de seguran?a ? longo prazo e promovendo a cicatriza??o de vasos vasculares (PR Newswire, 2010). Neste sentido, o presente trabalho desenvolveu a s?ntese de poliuretanos bioest?veis a partir da rea??o de policaprolactona diol (PCL) com diferentes diisocianatos (HDI e H12MDI), caracterizando-os por meio de an?lise morfol?gica (MEV), t?rmica (TGA e DSC), mec?nica (DMA) e estrutural (IV), como tamb?m, avaliando sua citotoxicidade in vitro, atrav?s de testes para a avalia??o da viabilidade celular (teste VN e MTT) e prolifera??o celular (teste Azul de Tripan) utilizando c?lulas fibrobl?sticas NIH-3T3, comparando-os com materiais comerciais, Dacron e PTFE. Os resultados obtidos mostraram que os poliuretanos sintetizados apresentaram massa molar ponderal m?dia (Mw) variando entre 30000 e 263000 g/mol, bem como, uma plasticidade dependente do poliol utilizado. O comportamento mec?nico destes poliuretanos mostrou-se semelhante ou superior aos materiais comerciais, Dacron e PTFE. Os testes de bioestabilidade mostraram que houve perda de massa abaixo de 20% dos materiais expostos ? degrada??o hidrol?tica no periodo de 270 dias e abaixo de 5% na degrada??o enzim?tica no periodo de 30 dias. A viabilidade celular dos poliuretanos mostrou-se superior a 80%, consideradas n?o citot?xicas. Os poliuretanos avaliados neste estudo apresentaram resultados favor?veis para seu uso como biomaterial em poss?veis aplica??es cardiol?gicas
2

Prepara??o de micro/nanopart?culas de poliuretano biodegrad?vel carreadoras de ?leo de a?a? e α tocoferol

Santos, Fabiana Gon?alves dos 06 March 2014 (has links)
Made available in DSpace on 2015-04-14T13:59:04Z (GMT). No. of bitstreams: 1 454476.pdf: 17188672 bytes, checksum: b9bae5126e1fa699d075b37bc4ae70fa (MD5) Previous issue date: 2014-03-06 / Searches in nanotechnology allied to studies of biopolymers advances for application in the medical / pharmaceutical field. Micro / nanoparticles (NP) with biodegradable polymer systems are promising for the controlled release of drugs in the form of nanocapsules (NC) or nanospheres (NS), able to protect / release the substance gradually. This work aims to prepare NP polyurethane (Mw = 224,973 g/ mol and Mn = 134 670 g / mol) for the encapsulation by multiple emulsion of the pharmaco α-tocopherol (α-TOC) with and without a?ai oil and different stirring techniques (ultra-turrax (TR) and ultrasound (SM)), as well as the study of controlled release in physiological medium. The average sizes of the obtained NP were between 600 nm and 10 μm using the SM and between 2-15 μm using the TR and all presented spherical morphology and variables distributions depending on the presence or absence of a?ai oil. It was also possible to detect the presence of α-TOC and a?ai oil (when present) in all NP's, as well as the degradation of PU and release of α-TOC through the techniques of UV-Vis, IR and TGA. The encapsulation efficiency of α-TOC was moderate, ranging between 15-34% for NPs obtained by TR and between 18-44% for NPs obtained by SM, due to the affinity of the hydrophobic compound with the PU. The amount of α-TOC initially added in the formulations obtained high rates of recovery ranging from 93-96%. The NPs showed a mass loss of less than 4% when exposed to hydrolytic degradation up to 30 days. The ultraturrax samples without a?ai oil and ultrasound with a?ai oil showed increased release of α-TOC from the 12th day, whereas NP's ultra-turrax with a?ai oil and ultrasound without acai oil showed constant release up to day 30. The results indicate that the presence of oil using the MS showed more efficiency in the formation of NPs / Pesquisas em nanotecnologia aliada aos estudos dos biopol?meros possibilitaram avan?os para aplica??o na ?rea m?dica/farmac?utica. Sistemas de micro/nanopart?culas (NP) com pol?meros biodegrad?veis s?o promissores na libera??o controlada de f?rmacos na forma de nanoc?psulas (NC) ou de nanoesferas (NE), capaz de proteger/liberar a subst?ncia gradativamente. Este trabalho tem como objetivo preparar NP de poliuretano (PU- Mw= 224.973 g/mol e Mn=134.670 g/mol) para o encapsulamento por emuls?o m?ltipla do f?rmaco α-tocoferol (α-TOC) com e sem ?leo de a?a? e com diferentes t?cnicas de agita??o (ultra-turrax (TR) e ultrassom (SM) ), bem como, o estudo de libera??o controlada em meio fisiol?gico. Os tamanhos m?dios das NP obtidas foram entre 600nm e 10 μm utilizando o SM e entre 2-15 μm utilizando o TR e apresentaram morfologia esf?rica e distribui??es vari?veis em fun??o da presen?a ou n?o de ?leo de a?a?. Tamb?m foi poss?vel detectar a presen?a de α-TOC e ?leo de a?a? (quando presente) em todas as NP s, assim como a degrada??o do PU e libera??o do α-TOC atrav?s das t?cnicas de UVVis, TGA e IV. A efici?ncia de encapsulamento do α-TOC foi moderada, variando entre 15 a 34% para as NP s obtidas por TR e entre 18 a 44% para as NP s obtidas por SM, devido ? afinidade deste composto hidrof?bico pelo PU. A quantidade de α- TOC inicialmente adicionada nas formula??es obteve tamb?m elevadas taxas de recupera??o, variando entre 93-96%. As NP s apresentaram uma perda de massa abaixo de 4% quando expostos a degrada??o hidrol?tica at? 30 dias. As amostras TR S/?LEO e SM C/?LEO apresentaram libera??o crescente de α-TOC a partir do 12? dia, enquanto que as NP s TR C/?LEO e SM S/?LEO apresentaram libera??o constante ate 30? dia. Os resultados indicam que a presen?a de ?leo e utiliza??o de SM mostraram-se mais eficiente na forma??o das NP s.
3

Comp?sitos tern?rios de poliuretano-TiO2-SiO2 : prepara??o, caracteriza??o e degrada??o

Santos, Cl?udia Andr?a Batista dos 26 August 2014 (has links)
Made available in DSpace on 2015-04-14T13:59:10Z (GMT). No. of bitstreams: 1 462026.pdf: 4874123 bytes, checksum: 1a15895448105e314b1f653aab8461a5 (MD5) Previous issue date: 2014-08-26 / The addition of inorganic fillers in polyurethane resins for use as coating has been of great technological interest because it leads to improvements in the properties and performance of existing materials, besides the possibility of reducing environmental impact and costs. In this context, this work presents the production of ternary composites with addition of commercial inorganics fillers, titanium dioxide (TiO2) and silica (SiO2), in aqueous polyurethane dispersions. These ternary composites were obtained from the addition of 1% of different combinations of proportion of fillers (TiO2: SiO2 = 0:100 25:75 50:50 75:25 to 100:0) in aqueous polyurethane dispersions (PUD) by the in situ polymerization process. The characteristics of the ternary composite were evaluated in the form of polymer dispersion (particle size, pH, viscosity and conductivity) and in the form of films (thermal, mechanical and morphological properties), as well as the study of degradation of these materials. The results show that the synergy resulting from the combination of the two fillers, SiO2 and TiO2, interferes with the formation of micelles in PUD colloidal system, changing the coalescence process in the formation of films and modifying light reflection and refraction in the composite making it opaque and matte. The presence of anatase crystalline phase in TiO2 particles provides better compatibility filler1-filler2-polymer increasing the tensile strength and thermal stability of the ternary composites. The presence of SiO2 retarded the degradation process in the soil of the ternary composites and they did not show biological material on the surface after degradation. / A adi??o de cargas inorg?nicas em resinas de poliuretano para aplica??o como revestimento tem tido grande interesse tecnol?gico, pois conduz a melhorias nas propriedades e no desempenho dos materiais j? existentes, al?m da possibilidade de redu??o de impacto ambiental e de custos. Neste contexto, este trabalho apresenta a produ??o de comp?sitos tern?rios com a adi??o de cargas inorg?nicas comerciais, di?xido de tit?nio (TiO2) e di?xido de sil?cio (SiO2), em dispers?es aquosas de poliuretano. Estes comp?sitos tern?rios foram obtidos a partir da adi??o de 1% de diferentes propor??es das cargas (TiO2:SiO2 = 0:100, 25:75, 50:50, 75:25 e 100:0) em dispers?es aquosas de poliuretano (DPU) pelo processo de polimeriza??o in situ. As caracter?sticas dos comp?sitos tern?rios foram avaliadas na forma de dispers?o polim?rica (tamanho de part?cula, pH, viscosidade e condutividade) e na forma de filmes (propriedades t?rmicas, mec?nicas e morfologia), bem como, o estudo de degrada??o destes materiais. Os resultados mostram que a sinergia resultante da combina??o das duas cargas, SiO2 e TiO2, interfere na forma??o das micelas no sistema coloidal DPU, alterando o processo de coalesc?ncia na forma??o dos filmes e modificando a reflex?o e a refra??o de luz no comp?sito deixando-o opaco e fosco. A presen?a da fase cristalina anatase nas part?culas de TiO2 propicia melhor compatibilidade carga1-carga2-pol?mero aumentando a resist?ncia a tra??o com altos percentuais de deforma??o e a estabilidade t?rmica dos comp?sitos tern?rios. A presen?a de SiO2 retardou o processo de degrada??o em solo dos comp?sitos tern?rios e estes n?o apresentaram material biol?gico na superf?cie depois da degrada??o.
4

S?ntese e caracteriza??o de poliuretano ramificado com potencial aplica??o em engenharia de tecidos / Synthesis and characterization of branched polyurethane with potential application in tissue engineering.

Hoffmann, Mauricio da Silva 04 March 2016 (has links)
Submitted by Setor de Tratamento da Informa??o - BC/PUCRS (tede2@pucrs.br) on 2016-07-26T14:16:17Z No. of bitstreams: 1 DIS_MAURICIO_DA_SILVA_HOFFMANN_COMPLETO.pdf: 3702613 bytes, checksum: 3b0ef365d0e0899c33cdef47ae74d886 (MD5) / Made available in DSpace on 2016-07-26T14:16:17Z (GMT). No. of bitstreams: 1 DIS_MAURICIO_DA_SILVA_HOFFMANN_COMPLETO.pdf: 3702613 bytes, checksum: 3b0ef365d0e0899c33cdef47ae74d886 (MD5) Previous issue date: 2016-03-04 / Polyurethanes (PU) are widely used as biomaterials because it has good compatibility, and desirable mechanical properties and branched polyurethanes have shown besides these characteristics, an appreciable stability to hydrolytic and enzymatic degradation. Within this context, this study aimed to synthesize branched polyurethanes from the addition of pentaerythritol and evaluate its potential use as scaffolds in tissue engineering. Polycaprolactone diol (PCL) as polyol and pentaerythritol (PETT) in different amounts (5, 10 and 15% w/w relative to the polyol) as well as the hexamethylene diisocyanate (HDI) were used in the synthesis of the branched PU. These branched PU (PU-PETT) were evaluated for structural, morphological, mechanical, thermal and solubility in various organic solvents and compared to the linear PU (without PETT). Among the branched PU, PU-PETT 5% showed better morphological and tensile strength characteristics, so it was used to prepare membranes leached with the linear PU. The leached membranes were evaluated for their structural, morphological, mechanical, thermal properties, wettability, hydrolytic degradation, calcification and swelling degree. The leached membrane PU-PETT 5% showed high porosity and interconnectivity, greater thermal stability compared to linear PU leached membrane, despite the lower degree of crystallinity and molar weight. Also, the PU-PETT 5% membrane exhibited the ability of calcium phosphate biomineralization, good wettability, higher stability hydrolytic degradation and greater swelling as compared to linear PU membrane. Thus, it can be concluded that the membrane PU-PETT 5% exhibited characteristics suitable for use as biomaterials in tissue engineering. / Poliuretanos (PU) t?m sido amplamente utilizados como biomaterial por possuir boa compatibilidade e desej?veis propriedades mec?nicas e os poliuretanos ramificados tem apresentado al?m destas caracter?sticas, apreci?vel estabilidade a degrada??o hidrol?tica e enzim?tica. Dentro deste contexto, este trabalho teve como objetivo sintetizar poliuretanos ramificados est?veis a partir da adi??o de pentaeritritol e avaliar seu potencial uso como suportes em engenharia tecidual. Para a s?ntese do PU ramificado foi utilizado o poliol policaprolactona diol (PCL) e pentaeritritol (PETT) em diferentes quantidades (5, 10 e 15% m/m em rela??o ao poliol), bem como, o hexametilenodiisocianato (HDI). Estes PU ramificados (PU-PETT) foram avaliados quanto ?s propriedades estruturais, morfol?gicas, mec?nicas, t?rmicas e de solubilidade em diversos solventes org?nicos e comparados ao PU linear (sem PETT). Entre os PU ramificados, o PU-PETT 5% apresentou melhores caracter?sticas morfol?gicas e de resist?ncia a tra??o, por isso ele foi utilizado para preparar membranas lixiviadas juntamente com o PU linear. As membranas lixiviadas foram avaliadas quanto as suas propriedades estruturais, morfol?gicas, mec?nicas, t?rmicas, molhabilidade, degrada??o hidrol?tica calcifica??o e grau de inchamento. A membrana lixiviada de PU-PETT 5% apresentou alta porosidade e interconectividade, maior estabilidade t?rmica comparada a membrana lixiviada de PU linear, apesar do menor grau de cristalinidade e massa molar. Al?m disso, a membrana de PU-PETT 5% apresentou habilidade para a biomineraliza??o de fosfato de c?lcio, boa molhabilidade, maior estabilidade a degrada??o hidrol?tica e maior grau de inchamento quando comparado a membrana de PU linear. Com isso, pode-se concluir que a membrana de PU-PETT 5% apresentou caracter?sticas adequadas para uso como biomaterial em engenharia de tecidos.
5

Obten??o e avalia??o do potencial imunoadjuvante de nanopart?culas de quitosana na produ??o de antissonoros contra venenos de serpentes e escorpi?es

Soares, Karla Samara Rocha 31 May 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-01-10T15:32:21Z No. of bitstreams: 1 KarlaSamaraRochaSoares_TESE.pdf: 2883085 bytes, checksum: 02667bee72d9ca986a7f49f759803663 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-01-11T15:56:53Z (GMT) No. of bitstreams: 1 KarlaSamaraRochaSoares_TESE.pdf: 2883085 bytes, checksum: 02667bee72d9ca986a7f49f759803663 (MD5) / Made available in DSpace on 2017-01-11T15:56:53Z (GMT). No. of bitstreams: 1 KarlaSamaraRochaSoares_TESE.pdf: 2883085 bytes, checksum: 02667bee72d9ca986a7f49f759803663 (MD5) Previous issue date: 2016-05-31 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Acidentes com animais pe?onhentos representam um s?rio problema de sa?de p?blica em diversos pa?ses, destacando-se os acidentes of?dicos e escorpi?nicos. No Brasil, as serpentes do g?nero Bothrops e os escorpi?es pertencentes ao g?nero Tityus, s?o as de maior relev?ncia cl?nica. O tratamento para o envenenamento consiste em administra??o de soros antiof?dico e antiescorpi?nico. Vacinas que utilizam ant?genos puros e vias de administra??o alternativa requerem o uso de adjuvantes potentes e um sistema de entrega de ant?geno eficaz. Nanossistemas v?m sendo investigados como sistemas de libera??o para macromol?culas terap?uticas. A quitosana, devido as suas propriedades, tem sido extensivamente investigada na formula??o de nanocarreadores, particularmente de genes e prote?nas. Este estudo teve como objetivo a obten??o de nanopart?culas de quitosana (CNP) com base na gelifica??o i?nica para carrear prote?nas/pept?deos terap?uticos utilizados na imunoterapia e avalia??o do potencial imunoadjuvante dessas nanopart?culas na produ??o de soros antivenenos. CNP foram obtidas por gelifica??o i?nica, com tamanho m?dio de 160 nm, caracterizadas f?sico-quimicamente e o perfil de libera??o avaliado, demonstrando se tratar de um sistema de libera??o modificado. A estabilidade dos sistemas foi avaliada por 7 semanas, observando-se uma maior estabilidade dos sistemas associados aos venenos. Animais experimentais foram imunizados durante 6 semanas com 100 ?L de veneno das serpentes atrav?s inje??es subcut?neas, em diferentes concentra??es (5,0 ou 10,0%), encapsuladas em CNP ou associados ao hidr?xido de alum?nio (HA). Os resultados demonstram que os t?tulos de anticorpos obtidos para os animais vacinados com os nanossistemas foram equivalentes ou maiores aos obtidos para os animais vacinados com o HA, com a vantagem desses serem menos inflamat?rios que o HA, exigindo uma menor quantidade de ant?geno a ser administrada, por se tratar de um sistema de liberta??o modificada, revelando a obten??o de um novo sistema nanoparticulado com potencial aplica??o na soroterapia. / Accidents with venomous animals represent a serious public health problem in many countries of the world, with emphasis to snake and scorpion accidents. In Brazil, Bothrops snakes are the most clinically relevant. Regarding scorpions, the genus Tityus includes the species of higher medical importance. Treatment for envenomation consists mainly in the administration of antivenom sera. Vaccines using pure antigens in alternative administration routes require the use of potent adjuvants and an effective antigen delivery system. Nanosystems are being investigated as delivery systems for therapeutic macromolecules. Chitosan, due to its properties, has been extensively investigated in nanocarriers formulations, particularly for genes and proteins. This study aimed to obtain chitosan nanoparticles (CNP) based on ionic gelation for the delivery of therapeutic proteins/peptides used in immunotherapy, as well as to evaluate the immunoadjuvant potential of these nanoparticles in the production of antivenom serums. CNP were obtained by ionic gelation, with an average size of 160 nm. Physicochemical characterization and evaluation of the release profile demonstrated that it is a modified release system. The stability of different systems was evaluated for 7 weeks, observing a greater stability of the systems associated with venoms. Experimental animals were immunized subcutaneously for 6 weeks with 100 uL snake venoms at different concentrations (5.0 or 10.0%), either encapsulated in CNP or associated with aluminum hydroxide (AH). The results demonstrate that the antibody titers observed for animals vaccinated with the studied nanosystems were equivalent or higher than those observed for animals vaccinated with HA. Further advantages of the nanosystems were to be less inflammatory, and to require smaller amounts of antigen to be administered, because it is a modified-release system, with potential application in anti-venom serum therapy.
6

S?ntese enzim?tica de ?steres de a??car: surfactantes e pol?meros como novos materiais ambientalmente seguros

Borges, Maur?cio Rodrigues 12 March 2007 (has links)
Made available in DSpace on 2014-12-17T14:07:23Z (GMT). No. of bitstreams: 1 MauricioRB.pdf: 2052566 bytes, checksum: ecabe62a65c1b9db9e09054f3321c5b1 (MD5) Previous issue date: 2007-03-12 / Sugar esters are substances which possess surfactant, antifungical and bactericidal actions and can be obtained through two renewable sources of raw materials: sugars and vegetable oils. Their excellent biodegradability, allied to lhe fact that they are non toxic, insipid, inodorous, biocompatible, no-ionic, digestible and because they can resist to adverse conditions of temperature, pH and salinity, explain lhe crescent use of these substances in several sections of lhe industry. The objective of this thesis was to synthesize and characterize surfactants and polymers containing sugar branched in their structures, through enzymatic transesterification of vinyl esters and sugars, using alkaline protease from Bacillus subtilis as catalyst, in organic medium (DMF).Three types of sugars were used: L-arabinose, D-glucose and sucrose and two types of vinyl esters: vinyl laurate and vinyl adipate. Aiming to reach high conversions from substrates to products for a possible future large scale industrial production, a serie of variables was optimized, through Design of Experiments (DOE), using Response Surface Methodology (RSM).The investigated variables were: (1) enzyme concentration; (2) molar reason of substrates; (3) water/solvent rale; (4) temperature and (5) time. We obtained six distinct sugar esters: 5-0-lauroyl L-arabinose, 6-0-lauroyl D-glucose, 1'-O-lauroyl sucrose, 5-0-vinyladipoyl L-arabinose, 6-0-vinyladipoyl D-glucose and 1 '-O-vinyladipoyl sucrose, being lhe last three polymerizable. The progress of lhe reaction was monitored by HPLC analysis, through lhe decrease of sugar concentration in comparison to lhe blank. Qualitative analysis by TLC confirmed lhe formation of lhe products. In lhe purification step, two methodologies were adopted: (1) chromatographic column and (2) extraction with hot acetone. The acylation position and lhe chemical structure were determined by 13C-RMN. The polymerization of lhe three vinyl sugar esters was possible, through chemical catalysis, using H2O2 and K2S2O8 as initiators, at 60?C, for 24 hours. IR spectra of lhe monomers and respective polymers were compared revealing lhe disappearance of lhe vinyl group in lhe polymer spectra. The molar weights of lhe polymers were determined by GPC and presented lhe following results: poly (5-0-vinyladipoyl L-arabinose): Mw = 7.2 X 104; PD = 2.48; poly (6-0-vinyladipoyl D-glucose): Mw = 2.7 X 103; PD = 1.75 and poly (1'-O-vinyladipoyl sucrose): Mw = 4.2 X 104; PD = 6.57. The six sugar esters were submitted to superficial tension tests for determination of the critical micelle concentrations (CMC), which varied from 122 to 167 ppm. Finally, a study of applicability of these sugar esters, as lubricants for completion fluids of petroleum wells was' accomplished through comparative analysis of lhe efficiency of these sugar esters, in relation to three commercial lubricants. The products synthesized in this thesis presented equivalent or superior action to lhe tested commercial products / ?steres de a??car s?o compostos que possuem a??o surfactante, antif?ngica e bactericida e podem ser obtidos a partir de duas fontes renov?veis de mat?ria-prima: a??cares e ?leos vegetais. Sua capacidade de se biodegradar, aliada ao fato de serem at?xicos, ins?pidos, inodoros, biocompat?veis, n?o-i?nicos, digest?veis e resistirem a condi??es severas de temperatura, pH e salinidade, explicam o crescente emprego destas subst?ncias em diversos setores da ind?stria. O objetivo desta tese foi sintetizar e caracterizar surfactantes e pol?meros, contendo a??cares ramificados em suas estruturas, atrav?s de transesterifica??o enzim?tica de ?steres vin?licos com a??cares, empregando-se protease alcalina de Bac?llus subtilis como catalisador, em meio org?nico (DMF). Foram empregados tr?s tipos de a??cares: L-arabinose, D-glicose e sacarose e dois tipos de ?steres vin?licos: laurato de vinila e adipato de vinila. Para a obten??o de altas convers?es de substratos em produtos, visando uma futura produ??o em larga escala, uma s?rie de vari?veis foram otimizadas, atrav?s de an?lise estat?stica experimental (DOE), por metodologia de resposta de superf?cie (RSM). As vari?veis investigadas foram: (1) a concentra??o de enzima; (2) a raz?o molar entre substratos; (3) a raz?o ?gua/solvente org?nico; (4) a temperatura e (5) o tempo. Foram obtidos seis ?steres de a??car: 5-0-lauroil L-arabinose, 6-0lauroil D-glicose, 1 '-O-Iauroil sacarose, 5-0-viniladipoil L-arabinose, 6-0viniladipoil D-glicose e 1 '-O-viniladipoil sacarose, sendo os tr?s ?ltimos polimeriz?veis. O progresso da rea??o foi monitorado por an?lise em HPLC, atrav?s do decr?scimo da concentra??o de a??car em rela??o ao branco. An?lises qualitativas, por TLC, confirmaram a forma??o dos produtos. Foram obtidas convers?es superiores a 98% na s?ntese do laurato de sacarose. Na purifica??o, foram adotadas duas metodologias: (1) coluna cromatogr?fica e (2) extra??o com acetona a quente. A posi??o de acila??o e a estrutura qu?mica foram determinadas por 13C-RMN. A polimeriza??o dos tr?s ?steres de a??car foi poss?vel, atrav?s de cat?lise qu?mica, empregando-se H2O2 e K2S2O8 como iniciadores, a 60?C, por 24 horas. Espectros de IR dos pol?meros foram comparados com os seus mon?meros, revelando o desaparecimento do grupo vinil. As massas molares dos pol?meros foram determinadas por GPC. Os pol?meros de a??car obtidos apresentaram as seguintes massas molares: poli (5-0-viniladipoil L-arabinose): Mw = 7,2 X 104; PD = 2,48; poli (6-0-viniladipoil D-glicose): Mw = 2,7 x 103; PD = 1,75 e poli (1 '-O-viniladipoil sacarose): Mw = 4,2 X 104; PD = 6,57. Os seis ?steres de a??car foram submetidos a ensaios de tens?o superficial para a determina??o das concentra??es micelares cr?ticas (CMC), que variaram de 122 a 167 ppm. Por fim, um estudo de aplicabilidade dos ?steres n?o polimeriz?veis, como lubrificantes para fluidos de completa??o de po?os de petr?leo foi realizado, atrav?s de an?lise comparativa da efici?ncia destes, em rela??o a tr?s lubrificantes comerciais. Os produtos sintetizados nesta tese apresentaram desempenho equivalente ou superior aos produtos comerciais testados

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