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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.
11

Avaliação e identificação de toxicidade em efluente da fabricação de resinas de poliester / Toxicity identification evaluation of polyester resin manufacturing wastewater

Caffaro Filho, Roberto Augusto 06 May 2008 (has links)
Orientador: Lucia Regina Durrant / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-10T19:47:18Z (GMT). No. of bitstreams: 1 CaffaroFilho_RobertoAugusto_D.pdf: 3860538 bytes, checksum: 5e0a12a4a24fb8f37e470a346d8bc95a (MD5) Previous issue date: 2008 / Resumo: Os processos industriais são geradores de uma ampla variedade de contaminantes que estão presentes nas águas residuarias. A seleção de processos de tratamento baseia-se nas características do efluente a ser tratado. Neste trabalho investigou-se um efluente tóxico da fabricação de resinas de poliéster. Existem poucas informações na literatura sobre este tipo de água residuaria. Procedeu-se a caracterização do efluente, efetuando-se a avaliação e identificação de constituintes tóxicos presentes no mesmo por meio de uma abordagem orientada por toxicidade. Foi utilizado bioensaio respirometrico em lodo ativado para avaliar a toxicidade do efluente bruto. Então, foram efetuados tratamentos físicos e químicos para fracionamento do efluente, e apos cada um deles, realizou-se o mesmo bioensaio. Dessa maneira, avaliou-se qual técnica de fracionamento foi a mais efetiva na redução da toxicidade. A maior redução de toxicidade foi observada apos o fracionamento do efluente por arraste com ar em pH 11 (62,5 %). Este resultado demonstrou que uma fração significativa da toxicidade do efluente para lodos ativados era causada por compostos orgânicos volatilizados em pH 11. Isso indica que o tratamento do efluente por arraste com ar em pH básico pode ter impacto positivo em um tratamento biológico aeróbio subseqüente. Uma vez determinado o tipo de compostos no efluente que provocam efeitos tóxicos (Compostos Organicos Volateis - COVs), procedeu-se a esforços analíticos visando a identificação dos mesmos. Analises por headspace do efluente por cromatografia gasosa e espectrometria de massa identificaram a presença de aldeidos insaturados (congeneres de acroleina). Tais compostos tinham relacao direta com o efeito tóxico observado. Foram também realizados bioensaios utilizando microrganismos anaerobios. Para tanto, mediu-se o volume de gas produzido por uma biomassa anaerobia em contato com o efluente bruto e com o efluente fracionado por arraste com ar em pH 11. Não se observou redução na toxicidade do efluente mesmo com este fracionamento. Comparando-se esses resultados aos obtidos com lodo ativados, foi verificado que os compostos removidos por arraste com ar em pH 11 não apresentaram o mesmo grau de toxicidade para esta biomassa anaerobia. Tais resultados indicam que a utilização de processo de tratamento biológico anaerobio seria uma opção adequada para a condução de futuros estudos de tratabilidade deste efluente. Os resultados obtidos neste trabalho de avaliação e identificação de toxicidade em efluente da fabricação de resinas de poliéster ratificam a abordagem utilizada como uma valorosa ferramenta na caracterização de efluentes industriais tóxicos, principalmente nos casos onde não se encontram disponíveis informações especificas relacionadas ao efluente estudado / Abstract: Industrial processes generate a vast range of contaminants that are present in wastewaters. Treatment process selection is based on wastewater characteristics. In this work a toxic polyester resin manufacturing wastewater was investigated. Specific literature on this kind of wastewater is rare. The characterization of this wastewater was conducted, evaluating and identifying toxicity by applying a toxicity-oriented approach. An activated sludge respirometric bioassay was used to assess effluent toxicity. Then, physical and chemical treatments were performed for effluent fractionation. After each fractionation, the same bioassay was conducted. In this way, it was assessed which fractionation technique was the most effective in reducing effluent toxicity. The greater toxicity reduction was observed after effluent fractionation with air stripping in pH 11 (62.5 %). This result showed that a significant fraction of wastewater toxicity for activated sludge was caused by organic compounds volatilized in pH 11. This indicates that effluent treatment by air stripping in basic pH could have a positive impact in a conjugated aerobic biological treatment. Once the type of compounds causing wastewater toxicity has been determined (Volatile Organic Compounds ¿ VOCs), analytical efforts aiming the identification of these compounds were made. Wastewater headspace gas chromatographic analyses coupled with mass spectrometry identificated the presence of a,ß-unsaturated aldehydes (acrolein congeners). These compounds were directly related to the observed toxic effect. Bioassays using anaerobic microorganisms were also conducted. To that purpose, the volume of gas produced by an anaerobic biomass in contact with the baseline effluent and with the fractionated effluent by air stripping in pH 11 was measured. No toxicity reduction was observed with this fractionation. By comparing this result with the one obtained with the respirometric bioassay, it was found that the compounds removed by air stripping in pH 11 did not inhibit this kind of biomass in the same degree which they inhibited activated sludge. This indicates that the use of an anaerobic treatment process would be an adequate option for conducting future treatability studies in this wastewater. The results obtained in this research of toxicity identification evaluation of a polyester resin manufacturing effluent confirm that the toxicity-oriented approach is a valuable tool for the characterization of toxic industrial wastewaters, especially in cases when specific information related to the studied wastewater is lacking / Doutorado / Doutor em Ciência de Alimentos
12

Compréhension et optimisation de la dispersion du carbonate de calcium dans une résine polyester insaturée / Comprehension and optimization of a calcium carbonate dispersion in an unsatured polyester resin

Kiehl, Julien 19 September 2012 (has links)
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.
13

Desenvolvimento e an?lise de material comp?sito a base de penas de frango (fibras de queratina-KF) e matriz de poli?ster insaturado

Galv?o, Alcione Olinto 26 August 2011 (has links)
Made available in DSpace on 2014-12-17T14:58:13Z (GMT). No. of bitstreams: 1 AlcioneOG_DISSERT.pdf: 4986234 bytes, checksum: d81c2eeeb91a55690b1f5b9671a9a5e3 (MD5) Previous issue date: 2011-08-26 / Use of natural fibres as a reinforcement material in the manufacture of composites show a series of advantages: availability, biodegradability, low weight and regeneration in relation to synthetic fibres, thus justifying its utilization. In the present research work, composites were developed with chicken feathers (KF), using unsaturated polyester resin as matrix, for diversified applications, mainly in the furniture/timber industry.At present, in Brazil the chicken feathers are used as part of the animal feed, even though this material possesses low aggregated value. The chicken feathers are hollow, light and resistant. After washing with water at room temperature, a part of the chicken feathers were treated with 2% NaOH. Composites were manufactured using treated and untreated chicken feathers with unsaturated orthothalic polyester resin and 1% peroxide as catalyser, obtained in the commerce. Samples with size 150x25x3 mm for mechanical tests were cut by laser in the composite plate. Mechanical analyses were carried out in the Laborat?rio de Metais e Ensaios Mec?nicos UFRN. All the analyses were in accordance with ASTM standards. SEM analyses were also carried out on the samples.In the analyses of the results obtained, it was observed that the composites made with untreated chicken feathers showed better results (Traction 11.406 MPa and 9.107 MPa Bending 34.947 and 20.918 MPa for samples with and without treatment respectively) compared to the composite with treated feathers. Very low values of the water absorption results, evidenced the impermeability characteristic of the feathers. From the SEM images, the structure, fracture and the fibre/matrix adsorption can be evidenced. In the flammability test, it was observed that despite the feathers having sulfur as a constituent, natural inhibitor of flame, no burning support of the composites, because the manufacturing process of the composite / O uso de fibras naturais como refor?o em comp?sitos apresenta uma s?rie de vantagens: abund?ncia, biodegradabilidade, baixo peso e regenerabilidade em rela??o ?s fibras sint?ticas, justificando sua utiliza??o. Na presente pesquisa foram desenvolvidos comp?sitos com penas de frango (KF), utilizando resina de poli?ster n?o-saturado como matriz. Atualmente, no Brasil, as penas de frango s?o utilizadas como parte de ra??o animal, por?m este produto possui um baixo valor agregado. As penas s?o um material oco, leve e resistente. Ap?s a lavagem com ?gua em temperatura ambiente uma parte das penas foi tratada com 2% de NaOH. Foram fabricados dois comp?sitos, um com as penas tratadas e outro sem tratamento, usando o processo de molde fechado por compress?o, utilizando a resina de poli?ster ortoft?lica e 1% de per?xido MEK (per?xido de metil etil cetona) como iniciador, adquiridos no com?rcio local. As amostras com 150x25x3 mm de tamanho para os ensaios mec?nicos foram cortadas a laser na placa do comp?sito. Os ensaios de tra??o e flex?o em tr?s pontos foram realizados no Laborat?rio de Metais e Ensaios Mec?nicos - UFRN. Todas as an?lises estavam de acordo com as normas da ASTM. As amostras resultantes dos ensaios mec?nicas foram avaliadas no MEV. Com base nas observa??es dos resultados nos ensaios mec?nicos, (Tra??o 11,2 Mpa e 8,3 Mpa; Flex?o 34,9 Mpa e 22,9 MPa para as amostras sem e com tratamento respectivamente) observou-se que os comp?sitos refor?ados com as penas sem tratamento apresentaram um melhor comportamento quando foram expostos a carregamentos tanto de tra??o quanto de flex?o. O ensaio de absor??o evidenciou nos valores de absor??o de ?gua, uma das caracter?sticas da prote?na existente nas penas, a queratina, a sua capaciade de impermiabiliza??o a ?gua. Nas imagens do MEV foi poss?vel verificar a estrutura da pena, as regi?es de ruptura do comp?sito e a ades?o fibra/matriz. No ensaio de inflamabilidade, observou-se que apesar das penas terem como constituinte o enxofre, inibidor natural de chama, n?o houve a susten??o da queima nos comp?sitos, devido o processo de fabrica??o do comp?sito
14

Untersuchung und Zähmodifizierung neuer hochtemperaturbeständiger ungesättigter Polyesterharze und ihrer Duromere

Stuck, Moritz 25 November 2019 (has links)
Zielsetzung dieser Arbeit war die Zähmodifizierung eines neuen besonders hochtemperaturbeständigen ungesättigten Polyesters, nachfolgend Referenz genannt. Im Rahmen dieser Arbeit wurden verschiedene konzeptionelle Ansätze verfolgt, um die Harz- und Duromer-Eigenschaften von hochtemperaturbeständigen ungesättigten Polyesterharzen (Unsaturated Polyester Resin, UPR) zu modifizieren und zu verstehen.:1. Einleitung 2. Motivation 3. Theoretischer Teil 4. Charakterisierungsmethoden 5. Ergebnisse und Diskussion 6. Zusammenfassung 7. Experimenteller Teil 8. Literaturverzeichnis 9. Anhang 10. Versicherung
15

IMPROVING WORKER SAFETY AND ENVIRONMENTAL PROTECTION BY UNDERSTANDING CHEMICAL EMISSIONS FROM PLASTIC COMPOSITES DURING MANUFACTURE AND USE

Seyedeh-Mahboobeh Teimouri-Sendesi (8755941) 21 June 2022 (has links)
<p>This dissertation focused on cured-in-place-pipe (CIPP) technology, which is being used to repair sewer pipes across the globe. The CIPP process involves the manufacture of a new fiber-reinforced composite plastic pipe inside an existing damaged pipe. By 2022, the global CIPP market will exceed $2.5 billion and constitute 40% of the U.S. pipe rehabilitation market. In recent years, concerns about the type, magnitude, and toxicity of chemical air emissions associated with CIPP installations have markedly increased. CIPP installations in Asia, Europe, Oceania, and North America have been associated with indoor and ambient air contamination incidents, afflicted schools, daycare centers, homes, and offices and prompted building evacuations. This research program was designed to better understand chemical release into the air during CIPP composite manufacture and the human health risks. Principles and techniques from the environmental engineering, air quality, material science, and risk analysis were applied. This dissertation contains three chapters and each chapter is a stand-alone manuscript, with the first chapter already having been published.</p><p>Chapter 1 involved the characterization of chemical emissions for steam-cured CIPP installations in Indiana (IN, sanitary sewer) and California (CA, storm sewer). It was discovered that a complex multiphase mixture of organic vapor, water vapor, and particulate (condensable vapor and partially cured resin) was emitted. Chemicals captured included a variety of hazardous air pollutants, carcinogens, endocrine disrupting compounds, and other chemicals with little toxicity data. The materials captured in California during 4 CIPP installations, when normalized against styrene concentration, exhibited different toxicity towards mouse cells. This toxicity indicated that non-styrene compounds were probably responsible for toxicity. Testing revealed significant and previously unreported worker and public safety chemical risks existed with CIPP installations.</p><p>Chapter 2 describes experiments conducted to determine which CIPP manufacturing conditions (i.e. curing pressure, temperature, time and ventilation) influenced chemical air emissions during and after composite manufacture. During thermal manufacture, approximately 8.87 wt% volatile organic compounds (VOC) was released into the air at standard pressure. For the CIPP styrene-based resin examined, chemical volatilization during manufacture was influenced by pressure, but temperature and heating time did not influence the composition of chemical residual inside the new composite. All cured composites, regardless of temperature or heating time, contained approximately 3 wt% VOC. No statistical difference was found for either: (1) VOC loading across cured composites or (2) styrene emission into the air across cured composites despite different curing temperature and heating times. Styrene was the most abundant compound detected in the composite and in air. High styrene air concentration signals inhibited the author’s ability to determine if other non-styrene compounds were emitted into the air. Short-term ventilation (2 hr) of the new composite reduced styrene air concentration to near zero in 10 min, but styrene levels rebounded when ventilation was halted. Due to the high styrene loading in the cured composite, it is expected that ventilation will only temporarily reduce VOC air levels in pipes, manholes, and other affected spaces.</p><p>Chapter 3 includes inhalation health risk assessment due to chemical emission from CIPPs during manufacture and use. Publicly available worksite data for ultraviolet (UV)-light and steam-CIPP installations were utilized and Monte Carlo simulation was applied. Data-gaps were also identified. Health risks associated with newly manufactured (post-cured) chemical emission from lab scale CIPPs were also evaluated. For CIPP resins and post-cured CIPPs 31 chemicals have been quantified among which many are unique volatile organic chemicals VOCs, but only 8 air testing studies were found. At a steam-CIPP worksite, VOCs were found in a condensed multiphase mixture discharged into air, 4 VOCs were detected in the vapor phase, while only styrene vapor phase results could be used for risk assessment. Worksite styrene levels (1,825 ppm<sub>v</sub>, 1,070 ppm<sub>v</sub>, 220-270 ppm<sub>v</sub>, 140 ppm<sub>v</sub>) have been reported indicating a health risk can exist. Monte Carlo simulation using literature data revealed that for the single UV-CIPP and single steam-CIPP study negligible styrene HQs were found, while unacceptable styrene LECRs% > 10<sup>−4</sup> (i.e. 37-38%) were obtained. Monte Carlo simulation on laboratory data showed that post-cured emissions from the composite cured longer increased the unacceptable styrene LECR (from 17.86% to 21.12%) and HQ (0.95% to 8.04%). Whereas curing the composite at greater temperature reduced the styrene LECR and HQ to 0.89%. and 0, respectively. Ventilation also diminished the acceptable LECR% in all composites but did not reduce the carcinogenic health risk to an acceptable level. Health risk can exist as evidenced by limited air testing data. More studies are needed to examine inhalation health risks associated with the CIPP manufacturing process and newly manufactured plastics.</p>
16

Проект малого предприятия ООО «МОДОС» : магистерская диссертация / The project of small enterprise LLC «MODOS»

Плехов, В. Н., Сергеев, Д. А., Plekhov, V. N., Sergeev, D. A. January 2023 (has links)
Магистерская диссертация посвящена открытию ООО «МОДОС» Магистерская диссертация содержит введение, 3 главы, заключение, библиографию и приложения. ООО Модос» - предприятие, специализирующееся на конструировании и изготовлении моделей и стержневых ящиков для литейных предприятий, использующих химически твердеющие смеси. Существующий рынок был проанализирован. В настоящее время много предприятий нуждаются в данном продукте, поскольку растет спрос на замену оборудования и запасные части. Использование полиэфирной смолы дает ряд преимуществ, таких как: Полиэфирная смола имеет высокую прочность и износостойкость; Угол смачивания полиэфирной смолы выше чем у модельных пластиков, что снижает количество прилипшей к поверхности моделей и стержневых ящиков смеси. Цена полиэфирной смолы меньше модельных пластиков на 30-40%, что есть основное преимущество для выбора материала. Проектируемое производство гарантирует конкурентоспособное изготовление моделей и стержневых ящиков благодаря грамотному конструированию, низкой себестоимости, высококачественным материалам и использованию современных фрезерных станков с ЧПУ. / Master’s thesis is devoted to establish limited liability company « MODOS » Master’s thesis consists of an introduction, 3 chapters, conclusion, references list and appendixes. LLC "MODOS" is a company specializing in the design and manufacture of patterns and core boxes for foundries using chemically bonded sand. The existing market has been analyzed. Currently, many companies need this product, as the demand for updating equipment and manufacturing spare parts for it has increased. Polyester resin materials has a number of advantages, such as: Polyester resin has higher strength and wear resistance; The wetting angle of the resin is much larger than that of plastics, which reduces the amount of adhesive sand to the surface of patterns and core boxes; The price of polyester resin is lower than plastics by 30-40%, which is the main advantage in choosing this material. The projected production will ensure competitive manufacture of patterns and core boxes due to competent design, low cost, use of high-quality materials and modern axis-controlled mill.
17

Integrated analysis of liquid composite molding (LCM) processes

Xu, Liqun 12 October 2004 (has links)
No description available.
18

Slídou modifikované elektroizolační laky / Mica modified electroinsulating varnishes

Mrkos, Pavel January 2010 (has links)
This master´s thesis deals with influence of mica content on the electrical properties of electrical insulating varnishes, particularly in the polyester resin Dolphon XL 2102. It focuses on diagnostic methods and testing the properties of electroinsulating varnishes. Examines the potential benefits of micronised mica in order to achieve better electrical insulation properties of the system compared to the matrix. The composite material consists of polyester resin Dolphon XL 2102, which is modified different mass percentage of micronized mica. The results of this project are frequency dependencies of real and imaginary parts of complex permitivity of varnish component.
19

Optimalizace plazmatických povrchových úprav skleněných vláken / Plasma surface modification of glass fibers and its optimization

Širjovová, Veronika January 2019 (has links)
Diploma thesis deals with glass fiber surface modification using plasma-enhanced chemical vapor deposition in order to prepare functional interface that enhances the properties of polymer composites. The effect of deposition conditions on shear strength was observed with respect to the chemical composition of the deposited film. Thin films were deposited on planar substrates and fibers using monomer tetravinylsilane in a mixture with oxygen at selected power of plasma discharge. Chemical composition of prepared material was analyzed by infrared spectroscopy. Planar substrate film adhesion was measured using the scratch test. The composite sample was prepared by embedding the surface modified fibers in unsaturated polyester resin, followed by the curing process. The cured composite sample underwent the short beam shear test.
20

Nanostructuration de résines polyester insaturé par des copolymères à blocs : application aux composites SMC et BMC / Nanostructuration of unsaturated polyester resins by block copolymers : application to SMC and BMC composites

Lamy, Yoann 06 September 2012 (has links)
On s’intéresse dans cette étude au potentiel de copolymères à blocs (BCP) de types PBA-b-P(MMA-co-DMA) et PBA-b-P(BA-co-DMA) en tant qu’additifs multifonctionnels nanostructurant la matrice thermodurcissable polyester insaturé de composites SMC et BMC. La nanostructuration de la résine polyester insaturé (UPR) est assurée par la ségrégation du bloc élastomère poly(acrylate de butyle), ainsi que par la miscibilité du deuxième bloc dans le réseau grâce à la bonne compatibilité des motifs diméthylacrylamide (auto-assemblage). Ces BCP sont tout d’abord étudiés en tant qu’agents renforçants et anti-retrait dans les composites SMC et BMC, en étant substitués et comparés aux additifs anti-retrait conventionnels PVAc et P(MMA-co-S) incorporés traditionnellement afin de compenser le retrait de la résine polyester. Ces additifs nanostructurants sont ensuite évalués en tant qu’agents de mûrissement des compounds SMC. La nanostructuration des BCP dans la résine UP réactive pouvant entrainer une importante augmentation de la viscosité (formation d’un gel), ces additifs pourraient peut-être constituer des agents de mûrissement plus efficaces que l’oxyde de magnésium couramment utilisé à cet effet. Une étude des matrices [UPR + BCP, UPR + PVAc et UPR + P(MMA-co-S)] est réalisée dans un premier temps, les composites BMC et SMC chargés par du carbonate de calcium et renforcés par des fibres de verre étant étudiés par la suite. En absence de charges et de fibres de verre (matrice seule), la nanostructuration est moins efficace que la macroséparation de phase des additifs conventionnels PVAc et P(MMA-co-S) pour compenser le retrait du réseau polyester. Dans un composite en revanche, la nanostructuration conduit à une compensation du retrait intermédiaire entre celles du P(MMA-co-S) et du PVAc. Au niveau de la matrice seule, la nanostructuration permet d’éviter une diminution conséquente de l’énergie de rupture du réseau polyester et permet même dans certains cas une amélioration significative de cette dernière, alors que les additifs conventionnels engendrent un effondrement de cette propriété. Cette différence est cependant beaucoup moins visible dans le cas des composites, les charges entrainant une fissuration prématurée de la matrice. Un composite nanostructuré peut tout de même présenter un renforcement significatif par rapport aux composites conventionnels lorsqu’il contient des nanovides compensateurs de retrait de tailles conséquentes qui améliorent la ténacité du matériau. En ce qui concerne le mûrissement d’un compound SMC par nanostructuration au cours du refroidissement (passage de la transition ordre-désordre), si l’augmentation de la viscosité d’un système réactif UPR + BCP semble suffisamment importante et abrupte, elle est cependant insuffisante en présence des charges ou alors intervient à une température trop faible en raison de l’influence de ces dernières sur la nanostructuration. / The aim of this study is to evaluate the potential of PBA-b-P(MMA-co-DMA) and PBA-b-P(BA-co-DMA) block copolymers (BCP) as multifunctional additives nanostructuring the unsaturated polyester thermosetting matrix of SMC and BMC composites. The nanostructuration of the unsaturated polyester resin (UPR) is ensured by the segregation of the poly(butyl acrylate) elastomeric block, and by the miscibility of the second block in the thermoset thanks to the good compatibility of dimethylacrylamide units (self-assembly). These BCP are first studied as reinforcing and anti-shrinkage agents in SMC and BMC composites, as compared to conventional low profile additives PVAc and P(MMA-co-S) traditionally blended to compensate the polyester resin shrinkage. These nanostructuring additives are then studied as thickening agents in SMC compounds. As the nanostructuration of BCP in the UP reactive resin can lead to a high viscosity increase (gel formation), BCP might provide a more efficient thickening than the conventional additive magnesium oxide. Matrices are studied first [UPR + BCP, UPR + PVAc and UPR + P(MMA-co-S)], BMC and SMC composites filled with calcium carbonate and reinforced by chopped glass fibres being then considered. In the absence of fillers and fibres (neat matrix), the nanostructuration is less efficient than the macrophase separation of PVAc and P(MMA-co-S) to compensate the polyester resin shrinkage. However, in a composite, the nanostructuration leads to an intermediate shrinkage compensation between those of P(MMA-co-S) and PVAc. In the neat matrix, the nanostructuration avoids a substantial decrease of polyester network toughness and can even lead sometimes to a significant reinforcement, whereas conventional additives decrease tremendously this property. However, this difference is not observed in composites, fillers giving rise to an early cracking of the matrix. A nanostructured composite can still present a significant reinforcement compared to conventional composites when it contains large nanovoids (compensating shrinkage) which improve the fracture toughness of the material. As regards the thickening of an SMC compound by nanostructuration during cooling (crossing of the order-disorder transition), the viscosity increase of a UPR + BCP reactive system seems important and sharp enough, but in the presence of fillers the viscosity increase is not sufficient or the order-disorder transition temperature is too low because of the influence of fillers on the nanostructuration.

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