No description available.

This thesis is an investigation of the TPE filament for Fused Deposition Modelling (FDM) manufacturing method. All the investigations aim to optimize the quality of the filament in order to make Thermoplastic Elastomer (TPE) material possible for FDM manufacturing method. Optimization experiments were made to find out key parameters in the extrusion process that determine the quality of the filament. With the optimal parameters, further investigation of the additive content in the TPE granulate was made to solve the current problem of the filament in practical 3D printing, which the high surface friction massively affects the FDM manufacturing feasibility. The filaments were manufactured by the desktop extruder 3devo filament extruder and the surface friction tests were performed on TribotesterTM. Additionally, discussion was made to summarize the pros and cons of TPE material as well as the significance of 3D printing TPE. Potential application and benefits are mentioned for combining the property of TPE and the advantage of FDM manufacturing. Current state-of-art extrusion equipment and FDM technology are also summarized.

No description available.

No description available.

Submitted by RENATO CARVALHO RESENDE (htc.renato@gmail.com) on 2017-03-30T23:23:31Z No. of bitstreams: 1 Dissertação Mestrado Renato Carvalho Resende.pdf: 9175175 bytes, checksum: 3d504c6ae855f8c5ee734700afd5a7cc (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2017-04-06T14:17:14Z (GMT) No. of bitstreams: 1 resende_rc_me_bauru.pdf: 9175175 bytes, checksum: 3d504c6ae855f8c5ee734700afd5a7cc (MD5) / Made available in DSpace on 2017-04-06T14:17:14Z (GMT). No. of bitstreams: 1 resende_rc_me_bauru.pdf: 9175175 bytes, checksum: 3d504c6ae855f8c5ee734700afd5a7cc (MD5) Previous issue date: 2017-03-06 / Os elastômeros termoplásticos (TPE) têm sido bastante empregados em substituição às borrachas tradicionais, por terem custo reduzido de matéria prima, facilidade no processamento e serem recicláveis. Apresentam propriedades mecânicas semelhantes, porém quando utilizados em componentes de vedação apresentam limitada resistência à corrosão em água clorada. Assim, o desenvolvimento de tratamento superficial que não modifique as características originais, mas tornem o material mais resistente são desejáveis. Para tanto, este trabalho pretende desenvolver uma metodologia a plasma para melhorar esse quesito. O elastômero termoplástico de copoliéster (COPE) foi escolhido por ser o mais empregado em componentes de vedação. O tratamento a plasma de baixa pressão com hexafluoreto de enxofre (SF6) foi empregado visando tornar a superfície do COPE hidrofóbica através da incorporação de grupos fluorados. A implantação iônica por imersão em plasmas (IIIP) de argônio foi utilizada para criar uma camada superficial mais coesa e entrelaçada, além da possibilidade de torná-la hidrofóbica após envelhecimento. Para o tratamento com SF6, os parâmetros de excitação do plasma (12 Pa e 80 W) foram mantidos, variando-se o tempo do tratamento entre 2 e 180 minutos de modo a encontrar uma condição ótima para esse processo. Para a IIIP de Ar os parâmetros de excitação do plasma (5 Pa e 60 min) foram mantidos e a potência da radiofrequência foi variada entre 10 e 150 W. A energia de superfície e ângulo de contato foram obtidos pelo método da gota séssil em um goniômetro automatizado. A morfologia da superfície foi avaliada por microscopia eletrônica de varredura (MEV) e microscopia de força atômica (AFM). Espectroscopia de energia dispersiva (EDS) e espectroscopia de fotoelétrons de raios X (XPS) foram utilizadas para análises da composição química e estrutura molecular. Corrosão por plasma de O2 e imersão em água clorada foram utilizados para avaliar a resistência antes e após os tratamentos a plasma. Os resultados mostram que as amostras tratadas por 90, 120 e 180 minutos em plasmas de SF6 tornam-se hidrofóbica, mesmo após o envelhecimento, apresentando incorporação de flúor, alterando assim a composição química e morfológica da superfície do COPE. Melhorias substanciais foram observadas nessas amostras após os ensaios de corrosão, indicando que um aumento na vida útil do material em situações reais de uso possam ter sido alcançadas. A IIIP de Ar tornou as amostras inicialmente mais hidrofílicas do que a amostra como-recebida, porém após a ação do tempo, algumas amostras permaneceram hidrofóbicas enquanto outras amostras retornaram à condição inicial. Apesar da hidrofobicidade não ter sido alcançada em todas as amostras, alterações na rugosidade e na morfologia foram verificadas, principalmente nas amostras tratada com 100 W de potência do plasma, ocasionando em melhora na resistência do COPE à água clorada. Essa melhora na resistência é atribuída ao aumento da conectividade da estrutura pelo estabelecimento de reticulações geradas pelo processo de IIIP, densificando o material tornando a permeação de íons da solução mais difícil. / Thermoplastic elastomers have been widely used in substitution for conventional rubber, given that the feedstock is cheaper, easier to process and recyclable. Its mechanical properties are similar, but when applied to sealing components its resistance is limited due to the chlorine present in water, therefore, it is interesting to develop a surface treatment that do not alter the original characteristics, but make the material more robust. To achieve such result, we chose to submit the copolyester thermoplastic elastomer (COPE) to plasma. This material was naturally chosen, once it is widely used for sealing purposes in this specific industry. By using low pressure plasma with sulfur hexafluoride, we expect to alter COPEs surface by incorporating fluorine groups, thus making it hydrophobic. We also submitted the sample to a second treatment, by submersion to argon plasma, making the outer layer less defective and more entangled with aging, as observed in previous experiments. For SF6 treatment, the exiting plasma parameters (12Pa and 80W) were kept and the treatment time was varied between 2 to 180 minutes in order to find the optimal treatment time. For Argon IIIP, the plasma exciting parameters (5Pa and 60 min) were maintained, while the radio frequency variation was between 10 to 150W. Surface energy and contact angle were obtained by and automatic goniometer, through the sessile drop method. The surface's morphology was analyzed by electronic scanning microscope and atomic force microscopy. Dispersive energy spectroscopy and X-ray photoelectric spectroscopy were responsible for the chemical composition and molecular structure analyses the new surface's resistance was tested by O2 plasma corrosion and immersed in chlorinated water. Results show the samples treated for 90,120 and 180 minutes in SF6 plasma became hydrophobic, even after aging. The samples were substantially improved and its resistance prolonged its lifespan in conventional usage. Argon IIIP made the surface more hydrophilic. However, after time part of the material restored its original characteristics. Although hydrophobic it was not achieved, the roughness and morphology alteration (especially when treated with 100W of plasma) improved COPE'S resistance. The results are explained by the increase in the structure's ability to connect by the establishment of reticulate one generated by the IIP process, making the component denser and the ionic solution less permeable.

<p>A novel strategy for synthesising segmented poly(urethane urea) (PUU) without using a chain extender but nevertheless with the opportunity to vary the hard segment content has been developed. The strategy is based on amine formation from isocyanate upon reaction with water. By adding a dissolved soft segment to an excess of diisocyanate followed by the addition of water in the gas phase, amines are formed <i>in situ</i>. Urea linkages are then formed when these amines react with the excess of isocyanate groups. The gas phase addition facilitates addition in a slow and continuous manner. The hard segment content can easily altered by varying the diisocyanate/soft segment ratio. Even though the strategy is shown to be applicable to different diisocyanates, the focus has been on the potentially biodegradable methyl-2,6-diisocyanatehexanoate (LDI) and 1.4-butanediisocyanate (BDI) and various well known biodegradable polyesters and polycarbonates. </p><p>All the synthesised materials exhibited pronounced phase separation and hydrogen bonding within the hard domains. However, a major increase in hydrogen bonding strength was seen when a symmetric diisocyanate was used instead of an asymmetric. Based on FTIR measurements, PUUs with BDI and a polydisperse hard segment can exhibit the same degree of phase separation and hydrogen bonding as the monodisperse product.</p><p>The elastic properties of this new group of PUUs were exceptional with an elongation at break from 1600% to almost 5000% and the elastic modulus could be varied from a few MPa up to a couple of hundreds. </p><p>Hydrolytic degradation was greater in the polyester-based than in the polycarbonate-based PUUs due to the more reactive ester bonds. Low mass loss but a considerable loss in molecular weight was seen in the polyester PUUs. The tensile strength decreased dramatically due to the loss of strain hardening.</p><p>An MTT seeding assay using human fibroblasts and an in vivo biocompatibility study were performed and no signs of cytotoxicity were seen and the inflammatory response was comparable to other inert polymers.</p><p>A biodegradable PUU with properties that can be tailored through an easy synthesis is here presented. </p>

A novel strategy for synthesising segmented poly(urethane urea) (PUU) without using a chain extender but nevertheless with the opportunity to vary the hard segment content has been developed. The strategy is based on amine formation from isocyanate upon reaction with water. By adding a dissolved soft segment to an excess of diisocyanate followed by the addition of water in the gas phase, amines are formed in situ. Urea linkages are then formed when these amines react with the excess of isocyanate groups. The gas phase addition facilitates addition in a slow and continuous manner. The hard segment content can easily altered by varying the diisocyanate/soft segment ratio. Even though the strategy is shown to be applicable to different diisocyanates, the focus has been on the potentially biodegradable methyl-2,6-diisocyanatehexanoate (LDI) and 1.4-butanediisocyanate (BDI) and various well known biodegradable polyesters and polycarbonates. All the synthesised materials exhibited pronounced phase separation and hydrogen bonding within the hard domains. However, a major increase in hydrogen bonding strength was seen when a symmetric diisocyanate was used instead of an asymmetric. Based on FTIR measurements, PUUs with BDI and a polydisperse hard segment can exhibit the same degree of phase separation and hydrogen bonding as the monodisperse product. The elastic properties of this new group of PUUs were exceptional with an elongation at break from 1600% to almost 5000% and the elastic modulus could be varied from a few MPa up to a couple of hundreds. Hydrolytic degradation was greater in the polyester-based than in the polycarbonate-based PUUs due to the more reactive ester bonds. Low mass loss but a considerable loss in molecular weight was seen in the polyester PUUs. The tensile strength decreased dramatically due to the loss of strain hardening. An MTT seeding assay using human fibroblasts and an in vivo biocompatibility study were performed and no signs of cytotoxicity were seen and the inflammatory response was comparable to other inert polymers. A biodegradable PUU with properties that can be tailored through an easy synthesis is here presented.

L’objectif de ce projet fut consacré à la synthèse d’un élastomère thermoplastique (TPE) innovant, utilisable en tant que joint entre des matrices composites. La polymérisation radicalaire contrôlée par des radicaux nitroxyde (NMP) fut choisie afin de produire des TPE copolymères à blocs de type styrénique. Le \uD835\uDEFD-myrcène (My) fut dans un premier temps sélectionné pour synthétiser le bloc souple poly(\uD835\uDEFD-myrcène) P(My). La NMP du My en masse à 120 oC en utilisant l’amorceur BlocBuilderTM fonctionnalisé avec l’ester succinimidyl (NHS-BB) fut très bien contrôlée, permettant l’extension de chaîne du macro-amorceur cis-1,4-P(My) avec du styrène (S). Les copolymères diblocs P(My-b-S) obtenus ayant une masse molaire moyenne en nombre modérée (Mn < 50 kg.mol-1) montrèrent un comportement fragile en test de traction uniaxiale (résistance à la rupture en traction σB < 1,1 MPa, allongement à la rupture en traction εB < 16%). L’incorporation d’unités fonctionnelles au sein du segment souple fut réalisée en parallèle via la NMP du My avec du méthacrylate de glycidyle (GMA) afin de favoriser possiblement le processus de soudage / collage entre le TPE et les composites thermoplastiques envisagés. Un amorceur bifonctionnel, le poly(éthylène-co-butylène)-(SG1)2 (SG1 = groupe nitroxyde), permit par la suite de synthétiser des copolymères triblocs S-My-S ayant une plus haute masse molaire moyenne Mn = 56-66 kg.mol-1 et une plus grande extensibilité (σB < 0,8 MPa, εB < 200%). Les segments PS furent remplacés par des segments ayant une température de transition vitreuse (Tg) plus élevée, à savoir des blocs poly(méthacrylate d’isobornyle) P(IBOMA) afin d’augmenter la résistance mécanique et la température de service du TPE candidat. Des triblocs de type IBOMA-My-IBOMA, dont les domaines furent micro-structurés, montrèrent de meilleures propriétés mécaniques (σB = 3,9 MPa, contrainte à la limite d’élasticité σY = 5,0 MPa, εB = 490%) et une température de service maximale d’environ 140 oC. Toutefois, ces TPE à base de My ne satisfirent pas le cahier des charges industriel à température ambiante, ce qui nous poussa à substituer le bloc flexible P(My) par du poly(isoprène) PI, ayant une masse molaire d’enchevêtrement bien plus faible. Des macro-amorceurs 1,4-PI bien définis et actifs furent d’abord étendus avec du styrène, ce qui permit d’obtenir des triblocs S-I-S auto-assemblés (Mn = 95-109 kg.mol-1, fraction molaire en styrène FS = 0,30-0,49, dispersité Đ = 2,11-2,29). σB = 4,1 ± 0,2 MPa et εB = 380 ± 60 % furent mesurés pour un S-I-S ayant FS = 0,38. Un tribloc de type IBOMA-I-IBOMA fut par la suite synthétisé (Mn = 94 kg.mol-1, Đ = 1,76, FIBOMA = 0,35) et montra de meilleures propriétés en contrainte-déformation (σB = 11,4 ± 0,6 MPa, εB = 1360 ± 210 %). / The aim of this study was to produce a novel thermoplastic elastomer (TPE), used as a tough and stable joining between composite matrices. Having typically thermo-reversible crosslinks, TPE can be processed as thermoplastics and exhibit elastic behavior similar to that of chemically crosslinked elastomers in a certain temperature range. Nitroxide-mediated polymerization (NMP) was selected to synthesize linear styrenic block copolymer TPE. \uD835\uDEFD-Myrcene (My) was first considered to manufacture the soft elastomeric segment poly(\uD835\uDEFD-myrcene) P(My) (glass transition temperature Tg ~ − 77 oC). NMP of My at 120 oC in bulk using succinimidyl ester-functionalized BlocBuilderTM alkoxyamine (NHS-BB) was well-controlled, allowing styrene (S) chain-extension from cis-1,4-P(My) macroinitiator. The resulting P(My-b-S) diblock copolymers, exhibiting relatively low number-average molar mass (Mn < 50 kg.mol-1), showed limited stress-strain behavior (ultimate tensile strength σB < 1.1 MPa, elongation at break εB < 16%). Meanwhile, the introduction of functional groups into the soft segment was implemented to subsequently aid the adhesive bonding / welding process between the TPE and the considered polar thermoplastic composites. Well-tailored epoxide functionalized P(My) were thereby synthesized by My/glycidyl methacrylate (GMA) nitroxide-mediated copolymerization. BlocBuilder-terminated poly(ethylene-co-butylene)-(SG1)2 (SG1 = chain-end nitroxide group) difunctional initiator was used to produce S-My-S triblock copolymers with Mn = 56-66 kg.mol-1, which exhibited improved extensibility (σB < 0.8 MPa, εB < 200%). Poly(styrene) PS blocks were then substituted by higher Tg blocks, namely poly(isobornyl methacrylate) P(IBOMA) to enhance the toughness and the service temperature of the candidate TPE. Micro-phase separated IBOMA-My-IBOMA type triblocks exhibited improved mechanical properties (σB = 3.9 MPa, yield strength σY = 5.0 MPa, εB = 490%) associated with an extended upper service temperature of about 140 oC. However, My-based TPE did not satisfy the ArianeGroup mechanical requirements at room temperature, which prompted us to replace P(My) by poly(isoprene) (PI), which has much lower entanglement molar mass compared to P(My). Well-defined and active 1,4-PI-(SG1)2 macroinitiators were first chain-extended with S, leading to self-assembled S-I-S triblocks (Mn = 95-109 kg.mol-1, molar fraction of S in the copolymer FS = 0.30-0.49, dispersity Đ = 2.11-2.29). With FS = 0.38, S-I-S showed σB = 4.1 ± 0.2 MPa and εB = 380 ± 60 %. IBOMA-I-IBOMA type copolymer was then produced (Mn = 94 kg.mol-1, Đ = 1.76, FIBOMA = 0.35) and improved stress-strain properties were obtained at room temperature (σB = 11.4 ± 0.6 MPa and εB = 1360 ± 210 %). Lastly, hydrogenation of I-based block copolymers was performed at normal pressure and resulted mostly in an enhanced thermal stability, a greater tensile stress at break and a reduced elongation at break.

No description available.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第24642号 / 工博第5148号 / 新制||工||1983(附属図書館) / 京都大学大学院工学研究科化学工学専攻 / (主査)教授 大嶋 正裕, 教授 竹中 幹人, 教授 佐野 紀彰 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM