The unsaturated polyester/silica hybrids have been synthesized via sol-gel process and characterized in an effort to obtain a transparent hybrid material in this study, with emphasis on the effects of silica precursors and coupling agents. Chemical properties, thermal properties, and morphology of the hybrids were investigated by Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results showed that silica particles can be dispersed homogeneously in the UP matrix; also, physical and chemical interactions at the interface between UP and silica can be enhanced by adding coupling agents into the system. From the thermal and chemical properties measurement, the decomposition temperature of UP backbone and the heat distortion temperature (HDT) of UP/Silica hybrid were higher than pure UP. Solvent-resistance of UP/Silica hybrid was also enhanced by adding coupling agents. A model illustrating the chemical and physical interaction at the interface due to the addition of coupling agents is proposed to explain the resulted obtained.

No description available.

Oligomers of soft and hard segments of unsaturated polyesters (UPE) were synthesized in two steps of esterification. For the hard segment, isophthalic acid was first reacted with 1,2-propanediol, then maleic anhydride was added for further esterification. For the soft segment, diethylene glycol was used to replace 1,2-propanediol. Oligomers of soft and hard segments were blended in different ratios, and then cured with various amount of styrene. Dynamic mechanical and the stress-strain properties of these cured UPEs were evaluated. The results indicated that both stress and strain were above the criteria of the inhibitors when the amount of hard segment oligomer was 30, 60 or 70 wt% of UPE, and the added styrene was 35 or 45 phr relative to UPE. The formula of 30 wt% hard segment, 70 wt% soft segment, and 45 phr styrene was selected for the following studies. Tetraethyl orthosilicate (TEOS) and poly(dimethyl siloxane) were incorporated into the uncured UPE resins via sol-gel process. Then fillers and 5, 10, 15, 20 or 30 wt% of magnesium hydroxide were blended with UPE resins and cured. Self-extinguished phenomenon was observed in the erosion tests when the amount of magnesium hydroxide was equal or higher than 15 wt% relative to UPE. After 101 days of nitroglycerin migration experiments, the migration rate and amount were significantly reduced for these filled specimens compared with the current formula of inhibitors. In addition, 2.5 or 5 phr of phenyl triethoxysilane (PhTES) relative to UPE was added together with TEOS to study the physical properties of the organic-inorganic hybrid materials. When the amount of PhTES was 2.5 phr, it was found that the miscibility between inorganic and organic components improved, and their stress- strain properties also satisfied the criteria of the inhibitors.

This study was conducted to investigate the effects of organoclay type and concentration on the nanocomposites synthesized by &ldquo / In-Situ Polymerization&rdquo / and &ldquo / Prepolymerization&rdquo / methods. In-Situ Polymerization Method was in fact a new route which consisted of dispersing the monomers / propylene glycol, maleic anhydride and o-phthalic anhydride into the galleries of montmorillonite followed by subsequent polymerization. The Prepolymerization Method involved the addition of montmorillonite to the previously synthesized unsaturated polyester. As the first step, all the compositions were prepared by Cloisite 30B, and then for comparison of clay type, nanocomposites containing 3 wt.% of Cloisite 15A and Cloisite 25A were also synthesized. The efficiency of the two methods were compared with regards to their structural, thermal and mechanical properties. According to the results of XRD analysis, in both methods, maximum intercalation was observed when Cloisite 30B was used. An exfoliated structure was obtained in the Prepolymerization Method at 3 wt. % Cloisite 30B content. In all clay types, the increase in the d-spacings of the organoclays was higher when the Prepolymerization Method was applied. With Cloisite 30B, maximum improvement in the impact strength was obtained at 3 wt. % organoclay loading and the In-Situ Method yielded better results leading to a 77% increase in the impact strength at this organoclay loading. Among the organoclay types, Cloisite 15A was found to give rise to maximum increase in the impact strength. With the Prepolymerization Method higher improvement in flexural strength and flexural modulus was obtained owing to the lower styrene content in the crosslinking medium. The elongation at break values followed a decreasing trend with increasing clay content but did not show any significant difference when the clay types were compared.

In this study, the effects of glycol type, organoclay type and concentration on the final properties of nanocomposites based on recycled poly(ethylene terephthalate) was investigated. For this purpose, first recycled PET was glycolysed and after that unsaturated polyester-montmorillonite nanocomposites were synthesized by using three different types of glycols (i.e. ethylene glycol (EG), propylene glycol (PG) and diethylene glycol (DEG)). As the first step, all the compositions were prepared by Cloisite 30B type of clay, and then for comparison of clay type, nanocomposites containing 1 wt. % of Cloisite 15A and Cloisite 25A type of clay were also synthesized. Morphological and mechanical analyses were performed for the characterization of the nanocomposites. According to the results of XRD analysis, for all glycol types maximum intercalation was observed in Cloisite 30B containing samples. Exfoliated structures were obtained in the samples containing EG at 1 wt. % Cloisite 30B content and DEG at 3 wt. % Cloisite 30B content. Mechanical tests showed that, for all properties, glycol type is the most effective experimental parameter. DEG based samples are the most flexible whereas PG based samples are the least flexible. EG and DEG based samples give maximum tensile strength and tensile modulus values at 1 wt. % clay loading. Samples prepared by DEG exhibited maxima in both flexural strength and modulus at 1 wt. % clay content. With respect to the organoclay type, Cloisite 30B containing samples gave the highest compatibility with the unsaturated polyester matrix as indicated by the tensile test results. Organoclay type and content had no positive effect on the impact strength. Clay particles acted as stress concentrators and lowered the impact strength.

Le contexte environnemental actuel contraint l’industrie automobile à trouver des solutions pour réduire les émissions de CO2 des véhicules. Une des voies développées consiste à alléger les véhicules en substituant les matériaux à densité élevée comme l’acier par des matériaux plus légers comme les composites. Parmi eux, les SMC (Sheet Molding Compound), généralement employés pour des applications semi-structurales, aspirent à des applications structurales, à condition d’améliorer leurs performances mécaniques (notamment en choc et en fatigue). Les SMC sont composés d’une phase polymère organique (réseau polyester ou vinylester associé à un additif anti-retrait), de charges inorganiques et de fibres de renfort. Cette étude s’est concentrée sur le rôle de la matrice (phase organique + charges) sur les propriétés à la rupture de formulations SMC à fibres de verre et fibres de carbone. Trois axes de recherche ont été développés : i) Analyse de l’existant en évaluant le rôle de l’additif anti-retrait et celui des charges sur les propriétés mécaniques de matrices SMC, ii) Renforcement de matrices SMC par l’utilisation de particules core-shell (CSR), iii) Evaluer le rôle de la matrice sur les SMC à partir des précédents résultats. Dans un premier temps, il a été montré que l’ajout d’un additif de type polystyrène, initialement immiscible dans une résine polyester, conduit à une diminution de la résistance au choc. L’impact de l’augmentation du taux d’un additif initialement miscible (polyester saturé ou polyacétate de vinyle) de faible Tg est gouverné par deux effets antagonistes : la présence de plus en plus importante d’une phase souple renforçante et le développement de microvides qui dégradent les propriétés mécaniques. Puis, l’effet des charges inorganiques a été analysé. Il a été montré que l’ajout de CaCO3 conduisait à une amélioration de la résistance à la propagation de fissure. La résistance à l’amorçage de fissure semble être liée au retrait de polymérisation. La diminution des propriétés à la rupture en présence de microsphères de verre a été démontrée. L’utilisation de charges alternatives a également été explorée. Dans un second temps, des matrices vinylester ont été renforcées par des particules core-shell, qui ont démontré leur efficacité en augmentant considérablement la résistance au choc et la ténacité des systèmes. Des analyses microscopiques ont permis d’identifier des mécanismes de renforcement. Enfin, le rôle de la matrice sur les SMC a été évalué. Ainsi, une augmentation du taux d’additif dans les SMC renforce la matrice et modifie probablement la résistance de l’interface fibre-matrice, entraînant une augmentation de la résistance au choc. L’ajout CaCO3 dégrade cette propriété. De plus, celui-ci masque l’effet renforçant des particules core-shell. Enfin, sur composites à fibres de carbone sans CaCO3, l’ajout de particules CSR permet d’augmenter jusqu’à 20% leur résistance au choc et d’améliorer leur tenue en fatigue. / Because of the current environmental context, automotive industry has to find solutions to reduce CO2 emissions of vehicles. In order to address this issue, one of the possible ways concerns the reduction of the overall weight of cars by substituting heavy steel parts by lightweight composite materials. Among composite materials, Sheet Molding Compounds (SMCs) are used in cars (semi-structural parts) thanks to their low cost and low weight. Their use in structural applications is relevant, provided that their mechanical properties are improved (especially in impact and fatigue). These composites are generally constituted of a polymer matrix (unsaturated polyester or vinylester resin blended with an anti-shrinkage additive) reinforced by short fibers and mineral fillers. The aim of this work was to evaluate the role of the matrix on the mechanical properties of carbon fibers (FC-SMC) and glass fibers-based SMC composite (FV-SMC). Three points were developed : i) a study of existing SMC formulations by assessing the influence of low-profile additive and inorganic fillers on the matrices mechanical properties, ii) a study of the toughening of SMC matrices by adding core-shell rubbers particles (CSR), iii), from the previous results, a last part to assess the impact of the matrix on SMC mechanical properties. First, it was shown that adding a polystyrene (PS) low-shrinkage additive, initially immiscible with a polyester resin (before polymerization), leads to a reduction of Charpy impact resistance, because of PS domains which act as defects. When an initially miscible low-Tg additive is used (PVAc or saturated polyester SP), two antagonist effects were found. When the amount of PVAc or SP was increased, a competition between composition (the presence of a soft phase is more important) and morphology (larger microvoids are created, which lead to a drop of fracture toughness) controlled the evolution of mechanical properties. Then, it was shown that CaCO3 improved fracture toughness of materials. Crack initiation resistance seemed to be lied to polymerization shrinkage. Adding glass microspheres led to a drop of mechanical properties. Other types of fillers were also investigated. In a second part, vinylester matrices were blended with CSR particles. An important toughening was obtained in comparison to a standard SMC matrix. Toughening mechanisms like CSR cavitation, plastic deformation of the matrix or crack-bridging were identified with electronic microscopic observations. Finally, the role of the matrix on SMC was studied. Increasing the rate of saturated polyester (low-profile additive) in FC- SMC formulations led to a better Charpy impact resistance, because of the higher matrix toughness and a probable modification of the fiber/matrix adhesion. With CSR particles in FV-SMC, the presence of CaCO3 limited the toughening. On FC-SMC without fillers, CSR particles led to a better Charpy impact resistance and a better fatigue behavior.

No description available.

Cette thèse porte sur le développement de résines polyesterimides insaturés pour des applications de type vernis d'imprégnation pour isolation électrique. Il s’agit de matériaux polymères thermodurcissables, qui assurent la double fonction d'isolant et d'agent de cohésion du système isolé. Ils se différencient en classes thermiques, qui définissent leur température maximale d'utilisation. Dans le cadre de cette étude, nous cherchons à développer des produits de classe thermique supérieure ou égale à 180°C. Une première partie de cette étude a porté sur l'amélioration de deux produits commerciaux à base de polyesters insaturés à fonctions terminales imides. Notre attention s'est portée sur la modification de leur structure chimique, afin de voir comment les différents précurseurs utilisés influencent les propriétés des résines. Une seconde partie a consisté à développer de nouvelles résines à base de polyesterimides insaturés, à partir de trois types de précurseurs imides difonctionnels. / This thesis focuses on the development of unsaturated polyesterimide resins as impregnating varnishes for electrical insulation applications. These thermosetting polymer materials provide the dual function of insulating and cohesion agent of the isolated system. They differ in thermal classes, which define their maximum operating temperature. In this study, we tried to develop products with a thermal class above or equal to 180°C. The first part of this study focused on the improvement of two commercial products based on imide-endcapped unsaturated polyester. Our attention turned to the modification of their chemical structure, to see how the different precursors used affect the thermal and mechanical properties of resins. A second part was to develop new unsaturated polyesterimide resins, using three types of difunctional imide precursors.

L’objectif de ce travail est d’adapter une formulation dispersante mise au point par la société Mäder à la dispersion de carbonate de calcium (CaCO3) dans une résine polyester insaturée (UP). Le carbonate de calcium est utilisé en tant que charge dans les matériaux composites à matrice thermodurcissable et en particulier dans les SMC (Sheet Molding Compound). Le rôle de cette formulation est de diminuer les viscosités de résines UP fortement chargées tout en conservant voire en améliorant les propriétés mécaniques des composites formés par un renforcement de l’interface charge / matrice. Trois grands axes ont été développés au cours de ce travail : - le comportement rhéologique d’un mélange CaCO3/résine UP a été déterminé et la formulation dispersante a été optimisée ; - la nature des interactions entre les différents constituants de la formulation dispersante et la surface du CaCO3 a été mise en évidence ; - de nouveaux polymères permettant une dispersion plus efficace de la charge dans la résine ont été synthétisés. Le mélange CaCO3 / résine UP présente un comportement rhéologique complexe. L’optimisation de la formulation dispersante a permis d’augmenter de plusieurs pourcents le taux de charge tout en conservant des viscosités inférieures à celle autorisée par le procédé industriel. L’étude des interactions des constituants de la formulation avec le carbonate de calcium a permis de déterminer les fonctions les plus réactives et de comprendre leur interaction avec la surface de la charge. La synthèse de nouveaux dispersants a également été effectuée. Ces derniers ont ensuite été testés dans l’application et ont montré une efficacité à disperser le CaCO3 dans la résine UP. / The aim of this study is to adapt a dispersive formulation developed by the Mäder group to the dispersion of calcium carbonate (CaCO3) in an unsaturated polyester resin (UP). The CaCO3 is commonly used as filler in the domain of composites especially for Sheet Molding Compound (SMC). This dispersive formulation is able to decrease the viscosity of UP resin containing a high amount of filler. In addition, the mechanical properties of composites could be increased by reinforcing the filler / matrix interface. Three main ways have been studied: - characterization of the rheological behavior of CaCO3 / polyester blends and optimization of the dispersive formulation ; - determination of the interactions between the dispersive formulation components and the CaCO3 surface ; - synthesis of new polymers in order to improve the CaCO3 dispersion in an organic matrix. A complex rheological behavior has been observed for CaCO3 / polyester blends. The dispersive formulation improvement led to an increasing of the filler percentage by keeping the viscosity under the industrial limit. The most reactive functions with the CaCO3 surface have been identified by studying the interactions between the dispersive formulation components and the CaCO3 surface. New dispersing agents have been synthesized. Their efficiency has been demonstrated for the dispersion of CaCO3 in a UP resin.

Made available in DSpace on 2014-12-17T14:07:00Z (GMT). No. of bitstreams: 1 GuilhermeFM.pdf: 1361832 bytes, checksum: 90befe7961c07f2510ca8f988b71da6b (MD5) Previous issue date: 2009-03-23 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / This work addresses the production of lightweight concrete building elements, such as plates, prefabricated slabs for pre-molded and panels of fencing, presenting a singular concrete: the Lightweight Concrete, with special properties such low density and good strength, by means of the joint use of industrial waste of thermosetting unsaturated polyesters and biodegradable foaming agent, named Polymeric Lightweight Concrete. This study covered various features of the materials used in the composition of the Polymeric Lightweight Concrete, using a planning of factorial design 23, aiming at studying of the strength, production, dosage processes, characterization of mechanical properties and microstructural analysis of the transition zone between the light artificial aggregate and the matrix of cement. The results of the mechanical strength tests were analyzed using a computational statistics tool (Statistica software) to understand the behavior and obtain the ideal quantity of each material used in the formula of the Polymeric Lightweight Concrete. The definition of the ideal formula has the purpose of obtaining a material with the lowest possible dry density and resistance to compression in accordance with NBR 12.646/92 (≥ 2.5 MPa after 28 days). In the microstructural characterization by scanning electron microscopy it was observed an influence of the materials in the process of cement hydration, showing good interaction between the wrinkled face of the residue of unsaturated polyesters thermosetting and putty and, consequently, the final strength. The attaining of an ideal formula, given the Brazilian standards, the experimental results obtained in the characterization and comparison of these results with conventional materials, confirmed that the developed Polymeric Lightweight Concrete is suitable for the production of building elements that are advantageous for construction / Neste trabalho ? abordada a aplica??o da tecnologia dos concretos leves ? produ??o de elementos construtivos, tais como placas pr?-fabricadas para lajes pr?-moldadas, pain?is de veda??o e pe?as pr?-moldadas, e ao desenvolvimento de um concreto celular com propriedades especiais de baixa densidade e boa resist?ncia mec?nica, em fun??o da utiliza??o conjunta de res?duo industrial de poli?ster insaturado termofixo (PIT) e espuma biodegrad?vel incorporadora de ar, denominado de Concreto Celular Polim?rico (CCP) . O estudo abrangeu diferentes tra?os dos materiais empregados na composi??o do CCP, sendo utilizado um planejamento fatorial 23, para an?lises dos processos de dosagem e produ??o, caracteriza??o das propriedades mec?nicas, bem como an?lises microestruturais da zona de transi??o entre o agregado artificial leve (PIT) e a matriz de cimento. Os resultados dos testes de resist?ncia mec?nica foram analisados utilizando-se uma ferramenta computacional de estat?stica (Statistica Software) para compreens?o do comportamento e obten??o da concentra??o ideal de cada material utilizado na formula??o do CCP. A defini??o da f?rmula ideal teve como finalidade a obten??o de um material com a menor densidade a seco poss?vel e resist?ncia ? compress?o que atendesse ? norma NBR 12.646/92 (≥ 2,5 MPa aos 28 dias). Na caracteriza??o microestrutural por microscopia eletr?nica de varredura, observou-se a influ?ncia dos materiais no processo de hidrata??o do cimento, onde constatou-se boa intera??o entre o res?duo de PIT, cuja face ? enrugada, e a pasta de cimento. A obten??o da formula??o de um novo material que atende ? norma brasileira, os resultados experimentais obtidos nas caracteriza??es e compara??o desses resultados com materiais convencionais, comprovaram que o Concreto Celular Polim?rico desenvolvido ? adequado ? produ??o de elementos construtivos que apresentam vantagens quando aplicados ? constru??o civil