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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

The adsorption and reaction of model adhesion promoters on metal and metal oxide surfaces

Woods, Georgina Ann January 1999 (has links)
No description available.
2

Epoxide biotransformation in non-conventional media

Prichanont, Seeroong January 1995 (has links)
No description available.
3

Compósitos formados por polietileno modificado e celulose: obtenção e caracterização / Composites made up of modified polyethyle and cellulose: obtainment and characterization

Casarano, Romeu 01 October 2004 (has links)
A primeira parte desta Tese incluiu a funcionalização em solução de polietileno linear de média densidade (LMDPE) com alil glicidil éter (AGE), na presença de peróxido de benzoíla (BPO) como iniciador de reações radicalares. A caracterização foi feita por espectroscopia no infravermelho com transformada de Fourier (FTIR) e o grau de funcionalização (GF) foi estimado por meio de duas curvas de calibração. Foi observado efeito do tipo de solvente sobre o GF. A segunda parte consistiu na funcionalização superficial por radiação ultravioleta (UV). Como monômeros foram usados AGE, anidrido maléico (MAH) e anidrido tetraidroftálico (THFAH). Como iniciadores, BPO e benzofenona (BP). A caracterização das superfícies foi realizada por medidas de ângulo de contato. THFAH apresentou a melhor performance. A terceira tratou da funcionalização por processamento reativo do LMDPE com AGE, na presença de BPO. A caracterização se deu por FTIR e o GF foi estimado conforme descrito acima. A funcionalização foi confirmada (indiretamente) por calorimetria diferencial exploratória, que evidenciou a diminuição do grau de cristalinidade com a funcionalização. Não foi possível confirmar a funcionalização por meio de análise elementar, termogravimetria e difração de raios X. A fragmentação das cadeias do LMDPE funcionalizado do ensaio 13 (e 13A) foi evidenciada por decréscimo no torque e nas propriedades mecânicas. Contudo, o índice de fluidez, surpreendentemente, diminuiu. Os valores relativamente superiores de resistência à tração e módulo de Young dos compósitos e blendas obtidos com LMDPE funcionalizado, contra os obtidos com LMDPE virgem, evidenciaram a interação favorável entre os grupos epóxidos inseridos nas cadeias do LMDPE e os grupos hidroxilas presentes no polissacarídeo. O aumento da adesão entre a matriz polimérica e as fibras de celulose foi confirmado por microscopia eletrônica de varredura e, qualitativamente, por quantidades relativamente maiores de resíduos remanescentes após extração em xileno sob refluxo. / The first part of this work included the functionalization in solution of linear medium density polyethylene (LMDPE) with allyl glycidyl ether (AGE), in the presence of benzoyl peroxide (BPO) as free radical reaction initiator. The characterization was made by Fourier transform infrared spectroscopy (FTIR) and the degree of functionalization was estimated by means of two calibration curves. The type of solvent influenced the DF. The second part comprised the surface functionalization by ultraviolet (UV) radiation. AGE, maleic anhydride (MAH) and tetrahydrophthalic anhydride (THFAH) were used as monomers and BPO and benzophenone (BP) as initiators. Contact angle measurements were used to characterize the surfaces. THFAH showed the best performance. The third part dealt with the functionalization by reactive processing of LMDPE with AGE, in the presence of BPO. FTIR was used to characterize the samples and the degree of functionalization was estimated as described above. The functionalization was (indirectly) confirmed by differential scanning calorimetry. The degree of crystallinity decreased with the functionalization. The functionalization couldn?t be confirmed by elemental analysis, thermogravimetry and X-ray diffraction. The chain scissions of the chemical modified LMDPE of trial 13 (and 13A) were evidenced by reduction of torque and mechanical properties. However, the melt flow index diminished. The favorable interaction between epoxide groups inserted on LMDPE chains and hydroxyl groups present in polysaccharide caused the increase in tensile strength and Young?s modulus values for composites and blends in relation to those obtained with virgin LMDPE. The increase in adhesion between the polymeric matrix and cellulose fibers was also confirmed by scanning electron microscopy and, qualitatively, by relatively large amounts of remaining residues after extraction in refluxing xylene.
4

Compósitos formados por polietileno modificado e celulose: obtenção e caracterização / Composites made up of modified polyethyle and cellulose: obtainment and characterization

Romeu Casarano 01 October 2004 (has links)
A primeira parte desta Tese incluiu a funcionalização em solução de polietileno linear de média densidade (LMDPE) com alil glicidil éter (AGE), na presença de peróxido de benzoíla (BPO) como iniciador de reações radicalares. A caracterização foi feita por espectroscopia no infravermelho com transformada de Fourier (FTIR) e o grau de funcionalização (GF) foi estimado por meio de duas curvas de calibração. Foi observado efeito do tipo de solvente sobre o GF. A segunda parte consistiu na funcionalização superficial por radiação ultravioleta (UV). Como monômeros foram usados AGE, anidrido maléico (MAH) e anidrido tetraidroftálico (THFAH). Como iniciadores, BPO e benzofenona (BP). A caracterização das superfícies foi realizada por medidas de ângulo de contato. THFAH apresentou a melhor performance. A terceira tratou da funcionalização por processamento reativo do LMDPE com AGE, na presença de BPO. A caracterização se deu por FTIR e o GF foi estimado conforme descrito acima. A funcionalização foi confirmada (indiretamente) por calorimetria diferencial exploratória, que evidenciou a diminuição do grau de cristalinidade com a funcionalização. Não foi possível confirmar a funcionalização por meio de análise elementar, termogravimetria e difração de raios X. A fragmentação das cadeias do LMDPE funcionalizado do ensaio 13 (e 13A) foi evidenciada por decréscimo no torque e nas propriedades mecânicas. Contudo, o índice de fluidez, surpreendentemente, diminuiu. Os valores relativamente superiores de resistência à tração e módulo de Young dos compósitos e blendas obtidos com LMDPE funcionalizado, contra os obtidos com LMDPE virgem, evidenciaram a interação favorável entre os grupos epóxidos inseridos nas cadeias do LMDPE e os grupos hidroxilas presentes no polissacarídeo. O aumento da adesão entre a matriz polimérica e as fibras de celulose foi confirmado por microscopia eletrônica de varredura e, qualitativamente, por quantidades relativamente maiores de resíduos remanescentes após extração em xileno sob refluxo. / The first part of this work included the functionalization in solution of linear medium density polyethylene (LMDPE) with allyl glycidyl ether (AGE), in the presence of benzoyl peroxide (BPO) as free radical reaction initiator. The characterization was made by Fourier transform infrared spectroscopy (FTIR) and the degree of functionalization was estimated by means of two calibration curves. The type of solvent influenced the DF. The second part comprised the surface functionalization by ultraviolet (UV) radiation. AGE, maleic anhydride (MAH) and tetrahydrophthalic anhydride (THFAH) were used as monomers and BPO and benzophenone (BP) as initiators. Contact angle measurements were used to characterize the surfaces. THFAH showed the best performance. The third part dealt with the functionalization by reactive processing of LMDPE with AGE, in the presence of BPO. FTIR was used to characterize the samples and the degree of functionalization was estimated as described above. The functionalization was (indirectly) confirmed by differential scanning calorimetry. The degree of crystallinity decreased with the functionalization. The functionalization couldn?t be confirmed by elemental analysis, thermogravimetry and X-ray diffraction. The chain scissions of the chemical modified LMDPE of trial 13 (and 13A) were evidenced by reduction of torque and mechanical properties. However, the melt flow index diminished. The favorable interaction between epoxide groups inserted on LMDPE chains and hydroxyl groups present in polysaccharide caused the increase in tensile strength and Young?s modulus values for composites and blends in relation to those obtained with virgin LMDPE. The increase in adhesion between the polymeric matrix and cellulose fibers was also confirmed by scanning electron microscopy and, qualitatively, by relatively large amounts of remaining residues after extraction in refluxing xylene.
5

Efeito do tipo de revestimento estetico e da eletroerosão sobre a desadaptação de infra-estruturas metalicas implantossuportadas / Influence of vennering material and spark erosion on marginal misfit of implant-suported frameworks

Oliveira, Luciana Valadares 26 June 2007 (has links)
Orientador: Marcelo Ferraz Mesquita / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-09T19:25:40Z (GMT). No. of bitstreams: 1 Oliveira_LucianaValadares_D.pdf: 36824583 bytes, checksum: 7a4d2a0d063c3cd9180327ea1a830f60 (MD5) Previous issue date: 2007 / Resumo: As distorções oriundas das técnicas de aplicação dos revestimentos estéticos sobre infraestruturas metálicas de próteses fixas podem resultar em margens cervicais desadaptadas. Este trabalho avaliou o efeito do tipo de revestimento estético, da simulação dos ciclos de cocção da porcelana e da eletroerosão sobre o desajuste de infra-estruturas implantossuportadas. Foi utilizada uma matriz metálica simulando um arco mandibular, contendo 5 pilares intermediários do tipo Microunit (Conexão Sistema de Próteses, Brasil). Sobre essa matriz, foram enceradas 40 infra-estruturas, fundidas em liga de CoCr (Remanium 2000, Alemanha). Para cada infra-estrutura, foi confeccionado um index, parafusando-se 5 réplicas em cada uma das infra-estruturas. Esse conjunto foi posicionado em gesso pedra especial com auxílio de delineador, antes da aplicação dos revestimentos estéticos, para avaliar o desajuste provocado apenas pela fase de aplicação dos revestimentos estéticos e ciclo de cocção da porcelana. As infra-estruturas foram separadas aleatoriamente: G1: resina acrílica termopolimerizável (Clássico, Clássico, Brasil); G2: resina fotopolimerizável (Versyo.com, Heraeus Kulzer, Brasil); G3: porcelana (Carmen, Dentaurum, Alemanha); G4: simulação dos ciclos de cocção da porcelana. Antes da aplicação dos revestimentos estéticos, foi realizada a avaliação do desajuste marginal sobre o index, após aperto de 10 Ncm em um único parafuso, correspondente ao implante A. Através desse procedimento, verificou-se a adaptação dos componentes C e E. O procedimento foi repetido no outro implante mais distal (E), para mensuração nos implantes A e C. As leituras foram realizadas utilizando microscópio mensurador (STN ¿ Olympus Optical, Japão). Procedeu-se o processo de eletroerosão (Tel Med Technologies, EUA), e novamente avaliação do desajuste marginal. Os resultados obtidos foram submetidos à Análise de Variância e teste de Tukey (p<0,05). Os valores de desajuste marginal das infra-estruturas antes da aplicação dos revestimentos estéticos não apresentaram diferença estatística significante entre si: G1: 56,97 µm (± 16,86); G2: 43,27 µm (± 16,49); G3: 49,26 µm (± 17,11); G4: 40,66 µm (+ 10,85). A aplicação dos revestimentos estéticos e simulação dos ciclos de cocção da porcelana aumentaram significantemente os valores médios de desajuste marginal para todos os grupos: G1: 170,01 µm (±53,98); G2: 72,32 µm (±27,49); G3: 164,84 µm (±27,67); e G4: 86,28 µm (±20,01). Os grupos G1 e G3 não apresentaram diferença estatisticamente significante entre si, mas apresentaram diferença quando comparados aos G2 e G4. Após eletroerosão, as médias de desajuste marginal apresentaram valores significamente menores para os grupos: Gl: 108, 54 µm (±40,75); G3: 109,61 µm (±24,42); e G4: 59,63 µm (±22,13). A média de desajuste marginal para o grupo de resina fotopolimerizável não apresentou diferença estatística significante: G2: 49,70 µm (±16,65). Como observado anteriormente, os grupos G1 e G3 não apresentaram diferença estatística significante, mas ambos apresentaram diferença dos grupos G2 e G4. Conclui-se que os revestimentos estéticos em resina acrílica e porcelana produzem os maiores valores de desajuste marginal para próteses implantossuportadas, enquanto a resina fotopolimerizável, os menores. A aplicação de porcelana resultou em maiores valores de desajuste marginal que apenas a simulação dos ciclos de cocção. A eletroerosão foi eficaz na redução dos desajustes marginais até os limites considerados clinicamente aceitáveis / Abstract: The demand for a passive fit of frameworks for osseointegrated endousseous implants abutments is well known, because the tightening of an inaccurate framework to the abutments can transmit stress to the bone-metal interface. The purpose of the present study was to evaluate the influence of the veneering application and porcelain firing cycle on the misfit level of implant-supported frameworks. Forty Co-Cr (Remanium 2000, Dentaurum, Germany) alloy frameworks were fabricated from a metallic index containing 5 Branemark type multi unit abutments. Analogs of the abutments were positioned to the framework, to construct an index for each framework. This index allowed the observation of the marginal gaps caused by the application of the veneering material. The frameworks were grouped (n=10): 1) heat acrylic resin (Clássico, Clássico, São Paulo, Brazil); 2) light polymerized resin (Versyo.com, Heraeus Kulzer, Brazil); 3) porcelain application (Carmen, Dentaurum, Germany); 4) simulation of porcelain firing cycle. Marginal refinement with spark erosion was conducted on specific equipment (Tel Med Technologies, U.S.A.). The marginal gap was obtained before and after the veneering materials and the spark erosion procedure, following the single screw test protocol (using a tightening force of 10 Ncm). A traveling microscope (STN ¿ Olympus Optical Co. Ltd Japan (120X) was used, tightening 10N in the titanium screw of the extremity distal implant, measuring the gaps at the central and distal implants. Data were subject Analysis of Variance followed by Tukey test (5%). Marginal gap mean values of the frameworks before the veneering application were not significantly different: G1: 56.97(± 16.86); G2: 43.27(± 16.49); G3: 49.26(± 17.11); G4: 40.66(± 10.85). The application veneering materials and the simulation of porcelain firing cycle increased significantly the misfit mean values of all groups: G1: 170.01 µm (±53.98); G2: 72.32 µm (+±27.49); G3: 164.84 µm (±27.67); e G4: 86.28 µm (±20.01). There were no significant differences between G1 and G3, but they were significantly different from both G2 and G3. After the spark erosion process, marginal gap mean values decreased significantly for the following groups: G1: 108. 54 µm (±40.75); G3: 109.61 µm (±24.42); and G4: 59.63 µm (±22.13). The light curing group decreased the marginal gap mean values, but not significantly after the spark erosion procedure: G2: 49.70 µm (±16.65). As occurred after the application of veneering materials, G1 and G3 groups did not show significant difference, but they both were significantly different from G2 and G4 groups. It can be concluded that heat cured acrylic resin and porcelain produced the highest mean values of marginal gaps, while light cured acrylic resin, the lowest. The application of porcelain produced higher misfit values than the simulation of porcelain firing cycles only. The spark erosion procedure was efficacious in reducing the frameworks marginal gaps to the levels clinically accepted for all groups evaluated. / Doutorado / Protese Dental / Doutor em Clínica Odontológica
6

The influence of reactive modification on the compatibility of polyolefins with non-olefinic thermoplastics

Lim, Henry C. A. January 2011 (has links)
Polyethylene (PE) resins being non-polar in nature and having a high degree of crystallinity have limited miscibility and compatibility when blended with polar polymers. The miscibility and compatibility of these blends are generally worsened when they are prepared by direct injection moulding without a precompounding process. Such situations are commonly encountered in particular by polymer converters when blending colour and/or additive concentrates, commonly known as masterbatches. Typically, masterbatches are mixtures containing high loading of pigments and/or additives predispersed in a suitable solid vehicle (commonly known as carrier) such as a polyethylene resin. These masterbatches are usually used for the colouration of a wide range of polymers and the carrier used must therefore be compatible with these matrix (host) polymers. The preliminary stage of this study involved the investigation of the properties of blends based on high density polyethylene (HDPE) and a range of engineering thermoplastics (ABS, PC, PBT, PA6), prepared by injection moulding. Five different types of compatibilisers namely, ethylene-vinyl acetate (EVA) copolymer, ethylene-methyl acrylate (EMA) copolymer, ethylene-glycidyl methacrylate (E-GMA) copolymer, ethylene-methyl acrylateglycidyl methacrylate (E-MA-GMA) terpolymer and maleic anhydride grafted HDPE (HDPE-g-MAH) copolymer were evaluated with respect to their efficiencies in compatibilising HDPE with the four engineering polymers. The pre-compounded HDPE/compatibiliser binary blends at 2 different blend ratios (1:1 and 3:1) were added at 15 wt% concentration to each engineering thermoplastics and test samples were produced directly by injection moulding. Results of mechanical testing and characterisation of the blends showed that glycidyl methacrylate compatibilisers, E-MA-GMA, in particular have the most universal compatibilising effectiveness for a range of engineering thermoplastics including ABS, PC, PBT, and PA6. Blends compatibilised with E-MA-GMA compatibiliser had the best notched impact performance irrespective of matrix polymer type. The presence of an acrylic ester (methyl acrylate) comonomer in E-MA-GMA resulted in increased polarity of the ii compatibiliser leading to improved miscibility with the polar matrix polymers demonstrated by fine blend morphologies, melting point depression and reduction in crystallinity of the HDPE dispersed phase. The second stage of this study involved the reactive modification of HDPE using a low molecular weight di-functional solid diglycidyl ether of bisphenol A (DGEBA) type epoxy resin compatibilised with HDPE-g-MAH in an attempt to improve its compatibility with ABS, PBT and PA6. The maleic anhydride moieties in HDPE-g-MAH served as reactive sites for anchoring the epoxy moieties while the HDPE backbone was miscible with the HDPE resin. An excessive amount of reactive groups resulted in the formation of crosslinked gels while the addition of EVA co-compatibiliser helped in the reduction of gel content and further improved the dispersion of the epoxy. The effectiveness of epoxy grafted HDPE (with and without EVA co-compatibiliser) in compatibilising ABS/HDPE, PBT/HDPE, and PA6/HDPE was investigated by injection moulding of 5 wt% functionalised HDPE with these matrix polymers into test bars for mechanical testing, and characterisation by differential scanning calorimtery (DSC) and optical microscopy. The reactively functionalised HDPE blends, improved the mechanical properties of ABS and PA6 blends especially with EVA as co-compatibiliser. However, the mechanical properties of PBT blends were unmodified by the functionalised HDPE which was believed to be due to end-capping of the PBT chain-ends by ungrafted epoxy resins.
7

Influência do sistema fotoiniciador nas propriedades fisicoquímicas de resinas experimentais / Influence of the photoinitiator system on physical-chemical properties of experimental resins

Furuse, Adilson Yoshio 19 May 2009 (has links)
O objetivo deste trabalho foi avaliar a influência de diferentes aminas terciárias no grau de conversão, na contração de polimerização, na taxa de contração, na microdureza Knoop, na estabilidade de cor e na transmitância de luz de resinas experimentais, contendo, em peso, BisGMA e TEGDMA (3:1), 0,25% de canforquinona (CQ) e 1% de amina (DMAEMA, CEMA, DMPT, DEPT ou DABE). A influência de diferentes protocolos de fotoativação também foi investigada. O grau de conversão foi avaliado através de FTIR-ATR e a contração pelo método do disco aderido. A partir da diferenciação numérica dos dados de contração em relação ao tempo, obteve-se a taxa de contração de polimerização. A estabilidade de cor e a transmitância foram avaliadas em diferentes períodos de envelhecimento artificial. Os resultados foram avaliados pelos testes de ANOVA, Tukey e T3 de Dunnett (&#945; = 0,05). As propriedades estudadas variaram em função da amina. O grau de conversão e a contração de polimerização variaram na sequência: CQ < DEPT < DMPT &#8804; CEMA &#8776; DABE < DMAEMA. O grau de conversão e a contração também foram influenciados pelo protocolo de fotoativação, sendo observadas correlações positivas entre o grau de conversão e a contração e entre o grau de conversão e a taxa de contração. A cor variou na sequência: DMAEMA < DEPT < DMPT < CEMA < DABE. A transmitância variou na sequência: DEPT &#8776; DABE < DABE &#8776; DMPT &#8776; CEMA < DMPT &#8776; CEMA &#8776; DMAEMA, sendo mais evidente para o comprimento de onda de 400nm. Não foram observadas correlações entre o grau de conversão e as propriedades ópticas. A resina contendo DMAEMA apresentou maior grau de conversão, contração, taxa de contração e dureza, além de melhor estabilidade nas propriedades ópticas. / The aim of this work was to evaluate de influence of different tertiary amines on degree of conversion (DC), shrinkage-strain, shrinkage-strain-rate, Knoop microhardness, and colour and transmittance stabilities of experimental resins containing BisGMA / TEGDMA (3:1 wt), 0,25wt% camphorquinone, 1wt% amine (DMAEMA, CEMA, DMPT, or DABE). Different light-curing protocols were also evaluated. DC was evaluated with FTIR-ATR and shrinkage-strain with the bonded-disc method. Shrinkage-strain-rate data were obtained from numerical differentiation of shrinkage-strain data with respect to time. Colour stability and transmittance were evaluated during different periods of artificial aging, according to ISO 7491:2000. Results were evaluated with ANOVA, Tukey and Dunnetts T3 tests (&#945; = 0.05). The studied properties varied according to amines. DC and shrinkage-strain were maximum at the sequence: CQ < DEPT < DMPT &#8804; CEMA &#8776; DABE < DMAEMA. Both DC and shrinkage were also influenced by the curing protocol, with positive correlations between DC and shrinkage-strain and DC and shrinkage-strain-rate. Colour varied in the sequence: DMAEMA < DEPT < DMPT < CEMA < DABE. Transmittance varied in the sequence: DEPT &#8776; DABE < DABE &#8776; DMPT &#8776; CEMA < DMPT &#8776; CEMA &#8776; DMAEMA, being more evident at the wavelength of 400nm. No correlations between DC and optical properties were observed. The resin containing DMAEMA showed higher DC, shrinkage-strain, shrinkage-strain-rate and microhardness, in addition with better optical properties.
8

Ternary Nanocomposites Of High Density, Linear Low Density And Low Density Polyethylenes

Ucar, Egemen 01 June 2007 (has links) (PDF)
In this study, the effects of organoclay loading, compatibilizer loading and polyethylene type on the morphology, rheology, thermal properties and mechanical properties of polyethylene/compatibilizer/organoclay nanocomposites were investigated. As compatibilizer, terpolymer of ethylene-methacrylate-glycidyl methacrylate (Lotader&reg / AX8900), as organoclay Cloisite&reg / 15A were used. All samples were prepared by a co-rotating twin screw extruder, followed by injection molding. Considering ternary nanocomposites, highest impact strength results were obtained with 10% compatibilizer plus 2% organoclay / highest yield stress, elastic modulus, flexural strength, flexural modulus were obtained with 5% compatibilizer plus 4-6% organoclay. DSC data indicated that addition of organoclay and compatibilizer did not change the melting point remarkably / on the other hand it affected the crystallinity. The organoclay used had no nucleation effect on polyethylene, and the compatibilizer decreased the crystallinity of the matrix. X-ray diffraction showed that in all ternary nanocomposites and in binary nanocomposite of high density polyethylene with organoclay, layer separation associated with intercalation of the clay structure occurred,. The highest increase of interlayer gallery spacing was obtained with 10% compatibilizer plus 2% organoclay, which were 25%, 28% and 27% for HDPE, LLDPE and LDPE matrices respectively.
9

Polymerpartikel für biomedizinische Anwendungen / Polymeric particles for biomedical applications

Häntzschel, Nadine 23 April 2008 (has links) (PDF)
Gegenstand dieser Arbeit ist die Herstellung funktioneller Polymerpartikel und deren Nutzung für biomedizinische Applikationen. Die Anwendungsgebiete der resultierenden Hybridmaterialien reichen vom Einsatz als Kontrastmittel in bildgebenden Verfahren der medizinischen Diagnostik über die Verwendung als Antimikrobium bis hin zum Einsatz als „Werkzeug“ zur Zellisolierung und aktivierung. Dazu wurden kompakte Latexpartikel und sensitive, poröse Mikrogelpartikel mittels emulgatorfreier Heterophasenpolymerisation synthetisiert. Als funktionelles Monomer wurde Glycidylmethacrylat verwendet, über dessen reaktive Epoxygruppen anschließend weitere Moleküle angebunden werden können. Die Funktionalisierung der Polymerpartikel erfolgte einerseits mit anorganischen Nanopartikeln (dotierte Lanthanfluorid-Nanopartikel, Gold- und Silbernanopartikel) und andererseits mit Biomolekülen wie Nukleotiden und Antikörpern. Einige Verwendungsgebiete, wie die Stimulierung von Memory-T-Zellen mit Antikörper-Polymer-Konjugaten oder der Einsatz der Silberkomposite aufgrund ihrer antimikrobiellen Wirkung, wurden näher untersucht. / The aim of this work was the synthesis of functional polymeric particles and their use for biomedical purposes. The application areas of the resulting hybrid materials range from contrast agents in medical diagnostics and usage due to antimicrobial properties to “tools” for cell isolation and activation. Compact core-shell particles and porous microgel particles were prepared by surfactant-free heterophase polymerization in water. All particles contain glycidyl methacrylate whose epoxy groups are capable to bind other molecules covalently. On the one hand, polymeric particles were functionalized with inorganic nanoparticles (doped lanthanum fluoride nanoparticles, gold and silver nanopariticles) and on the other hand with biomolecules such as nucleotides and antibodies. Selected application fields like the stimulation of memory T-cells with polymer-antibody-conjugates or the use of the silver composites due to their antimicrobial activity were investigated in detail.
10

Influência do sistema fotoiniciador nas propriedades fisicoquímicas de resinas experimentais / Influence of the photoinitiator system on physical-chemical properties of experimental resins

Adilson Yoshio Furuse 19 May 2009 (has links)
O objetivo deste trabalho foi avaliar a influência de diferentes aminas terciárias no grau de conversão, na contração de polimerização, na taxa de contração, na microdureza Knoop, na estabilidade de cor e na transmitância de luz de resinas experimentais, contendo, em peso, BisGMA e TEGDMA (3:1), 0,25% de canforquinona (CQ) e 1% de amina (DMAEMA, CEMA, DMPT, DEPT ou DABE). A influência de diferentes protocolos de fotoativação também foi investigada. O grau de conversão foi avaliado através de FTIR-ATR e a contração pelo método do disco aderido. A partir da diferenciação numérica dos dados de contração em relação ao tempo, obteve-se a taxa de contração de polimerização. A estabilidade de cor e a transmitância foram avaliadas em diferentes períodos de envelhecimento artificial. Os resultados foram avaliados pelos testes de ANOVA, Tukey e T3 de Dunnett (&#945; = 0,05). As propriedades estudadas variaram em função da amina. O grau de conversão e a contração de polimerização variaram na sequência: CQ < DEPT < DMPT &#8804; CEMA &#8776; DABE < DMAEMA. O grau de conversão e a contração também foram influenciados pelo protocolo de fotoativação, sendo observadas correlações positivas entre o grau de conversão e a contração e entre o grau de conversão e a taxa de contração. A cor variou na sequência: DMAEMA < DEPT < DMPT < CEMA < DABE. A transmitância variou na sequência: DEPT &#8776; DABE < DABE &#8776; DMPT &#8776; CEMA < DMPT &#8776; CEMA &#8776; DMAEMA, sendo mais evidente para o comprimento de onda de 400nm. Não foram observadas correlações entre o grau de conversão e as propriedades ópticas. A resina contendo DMAEMA apresentou maior grau de conversão, contração, taxa de contração e dureza, além de melhor estabilidade nas propriedades ópticas. / The aim of this work was to evaluate de influence of different tertiary amines on degree of conversion (DC), shrinkage-strain, shrinkage-strain-rate, Knoop microhardness, and colour and transmittance stabilities of experimental resins containing BisGMA / TEGDMA (3:1 wt), 0,25wt% camphorquinone, 1wt% amine (DMAEMA, CEMA, DMPT, or DABE). Different light-curing protocols were also evaluated. DC was evaluated with FTIR-ATR and shrinkage-strain with the bonded-disc method. Shrinkage-strain-rate data were obtained from numerical differentiation of shrinkage-strain data with respect to time. Colour stability and transmittance were evaluated during different periods of artificial aging, according to ISO 7491:2000. Results were evaluated with ANOVA, Tukey and Dunnetts T3 tests (&#945; = 0.05). The studied properties varied according to amines. DC and shrinkage-strain were maximum at the sequence: CQ < DEPT < DMPT &#8804; CEMA &#8776; DABE < DMAEMA. Both DC and shrinkage were also influenced by the curing protocol, with positive correlations between DC and shrinkage-strain and DC and shrinkage-strain-rate. Colour varied in the sequence: DMAEMA < DEPT < DMPT < CEMA < DABE. Transmittance varied in the sequence: DEPT &#8776; DABE < DABE &#8776; DMPT &#8776; CEMA < DMPT &#8776; CEMA &#8776; DMAEMA, being more evident at the wavelength of 400nm. No correlations between DC and optical properties were observed. The resin containing DMAEMA showed higher DC, shrinkage-strain, shrinkage-strain-rate and microhardness, in addition with better optical properties.

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