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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

Reclamation and Reprocessing of Thermotropic Liquid Crystalline Polymer from Composites of Polypropylene Reinforced with Liquid Crystalline Polymer

Collier, Monty C. 28 July 1998 (has links)
The composites industry can be positively influenced by composite materials that are processed faster, are lighter in weight, are higher in stiffness and strength, and that are more recyclable. There has been considerable interest in the use of thermotropic liquid crystalline polymers (TLCPs) to reinforce thermoplastic materials. In a novel process developed by Baird and coworkers, wholly thermoplastic composites are produced via a patented, dual extrusion process. This unique process yields a fiber which consists of numerous continuous fibrils of the liquid crystalline polymer encased in a thermoplastic matrix. These fibers have been used to form random mats and woven pre-forms, which have then been compression molded to form composite parts. Because of the high cost associated with these thermotropic liquid crystalline polymers and the desire to generate recyclable composites, a process was developed in this research to separate the liquid crystalline component from polypropylene (PP) composites. The overall objectives of this work were to develop a process to reclaim the liquid crystalline component of these thermoplastic composites, to determine the effect the process had on the properties of the reclaimed liquid crystalline polymer, and finally to determine whether or not the reclaimed liquid crystalline polymer could be used again to generate a reinforcing component. An ancillary objective was to see if the polypropylene could also be reclaimed, and if it had further use as a polymeric resin. In the present work, a novel process was developed that allows the liquid crystalline component to be reclaimed for further use in the composite material or in other applications that require thermotropic liquid crystalline polymers. The polypropylene component, which has undergone molecular weight reduction, can also be reclaimed by this process. This process consisted of using an organic peroxide and reactive extrusion to selectively degrade only the polypropylene, and not the thermotropic liquid crystalline polymer. The degraded polypropylene was selectively dissolved away from the liquid crystalline polymer by stirring the extruded melt in boiling mineral oil. The remaining solids, of thermotropic liquid crystalline polymer, were collected via centrifugation, cleaned of the mineral oil by boiling in kerosene, and then dried in a convection oven. The purity of the reclaimed thermotropic liquid crystalline polymer was determined by density measurements, while the physical properties of the reclaimed material were determined by rheological tests. The mechanical properties were determined via Instron testing of injection molded plaques made from mixtures of reclaimed material and pure thermotropic liquid crystalline polymer. From this work, it was found that over 70 wt% of the thermotropic liquid crystalline polymer, DuPont HX8000, could be successfully separated from the polypropylene to a degree of 96.0%. From Instron testing, it was found that up to 40 wt% of the reclaimed HX8000 could be blended with the pure HX8000, with no loss in mechanical properties. Furthermore, it was seen that up to 83 % of the HX8000 component (40 wt%) of PP 6523 (60 wt%) composites could be replaced with reclaimed HX8000 without seeing any losses in mechanical properties. It was also found that the degraded polypropylene could be successfully separated, via centrifugation at a temperature of 253 K, and could be potentially used as resin for non-wovens. The projected material cost of the reclaimed HX8000, based on the ability to purchase and to process in bulk, was determined to be 90 % less than the virgin HX8000. / Master of Science
2

Alternativas para o Reaproveitamento de Rejeitos Industriais de Poli(tereftalato de etileno) Reciclado / Alternatives for recycling of industrial wastes of recycled poly (ethylene terephthalate)

Bimestre, Breno Heins 05 July 2010 (has links)
A produção de mantas de tecido não tecido (TNT) por processo de extrusão a partir do poli(tereftalato de etileno) (PET) reciclado é uma forma interessante de reciclagem de polímeros adotada pela indústria que consegue conciliar viabilidade econômica com benefícios ambientais. Entretanto, durante a etapa de extrusão, muito material é perdido devido a entupimentos do equipamento ou outros motivos que acarretam na geração de uma quantidade considerável de rejeitos que não podem ser reaproveitados no sistema, devido à depreciação de propriedades ocorridas no material durante o processamento, levando ao descarte deste material geralmente em aterros sanitários. Neste trabalho foi feito um estudo sobre a reciclagem de rejeitos de PET das linhas de produção de mantas de tecido não tecido (TNT), adotando aditivos do tipo extensores de cadeia, para recuperar as propriedades que haviam sofrido grande depreciação. A incorporação de extensores de cadeia do tipo anidridos, isocianatos e fosforados, por meio de extrusão reativa, proporcionou melhorias consideráveis nas propriedades químicas, mecânicas e reológicas do rejeito de PET como aumento de massa molar, aumento de iscosidade no fundido e resistência à tração, facilitando o processamento e favorecendo a utilização do rejeito em novas etapas de reciclagem mecânica. Para as indústrias, a possibilidade de converter custos relacionados às operações de descarte de rejeitos em lucros com a agregação de valor a estes rejeitos poliméricos é extremamente interessante. Da mesma forma, a diminuição do volume de materiais poliméricos depositados no meio ambiente significa menos poluição e menos contaminação a diversos ecossistemas, apoiando os esforços que estão sendo feitos para a preservação e redução de poluentes na natureza. / The production of nonwoven fabrics (NWF) by extrusion process from recycled poly(ethylene terephthalate) (PET) is an interesting way for polymer recycling used by industry which to allow conciliate economic viability with environmental benefits. However, during extrusion step, a fraction of material is lost due to equipment clogging or others factors, leading to production of considerable amount of wastes which can not reinserted in system, due to the depreciation of material properties that occurs during thermal-mechanical processing. These rejects are generally deposited in land wastes. In this work was carried out a study about recycling of PET wastes from NWF production lines, using additives of chain extender kind to recoup properties that had been highly depreciated. The incorporation of chain extenders of kind anhydride, isocyanate and phosphorous compounds by reactive extrusion improved considerably some chemical, mechanical and rheological properties of PET waste such as increase in molecular weight, melt viscosity and strain strength, easing the thermal-mechanical processing and making possible the use of PET waste in news steps of mechanical recycling. The possibility to convert expenditures with wastes discarding operations into profits due to the values aggregation on these polymeric wastes is very interesting for the industries. Then, the decrease of amount of polymeric materials deposited in natural environment signifies less contamination to several ecosystems, supporting the works that have been realized to decrease pollutants and to preserve the nature.
3

Alternativas para o Reaproveitamento de Rejeitos Industriais de Poli(tereftalato de etileno) Reciclado / Alternatives for recycling of industrial wastes of recycled poly (ethylene terephthalate)

Breno Heins Bimestre 05 July 2010 (has links)
A produção de mantas de tecido não tecido (TNT) por processo de extrusão a partir do poli(tereftalato de etileno) (PET) reciclado é uma forma interessante de reciclagem de polímeros adotada pela indústria que consegue conciliar viabilidade econômica com benefícios ambientais. Entretanto, durante a etapa de extrusão, muito material é perdido devido a entupimentos do equipamento ou outros motivos que acarretam na geração de uma quantidade considerável de rejeitos que não podem ser reaproveitados no sistema, devido à depreciação de propriedades ocorridas no material durante o processamento, levando ao descarte deste material geralmente em aterros sanitários. Neste trabalho foi feito um estudo sobre a reciclagem de rejeitos de PET das linhas de produção de mantas de tecido não tecido (TNT), adotando aditivos do tipo extensores de cadeia, para recuperar as propriedades que haviam sofrido grande depreciação. A incorporação de extensores de cadeia do tipo anidridos, isocianatos e fosforados, por meio de extrusão reativa, proporcionou melhorias consideráveis nas propriedades químicas, mecânicas e reológicas do rejeito de PET como aumento de massa molar, aumento de iscosidade no fundido e resistência à tração, facilitando o processamento e favorecendo a utilização do rejeito em novas etapas de reciclagem mecânica. Para as indústrias, a possibilidade de converter custos relacionados às operações de descarte de rejeitos em lucros com a agregação de valor a estes rejeitos poliméricos é extremamente interessante. Da mesma forma, a diminuição do volume de materiais poliméricos depositados no meio ambiente significa menos poluição e menos contaminação a diversos ecossistemas, apoiando os esforços que estão sendo feitos para a preservação e redução de poluentes na natureza. / The production of nonwoven fabrics (NWF) by extrusion process from recycled poly(ethylene terephthalate) (PET) is an interesting way for polymer recycling used by industry which to allow conciliate economic viability with environmental benefits. However, during extrusion step, a fraction of material is lost due to equipment clogging or others factors, leading to production of considerable amount of wastes which can not reinserted in system, due to the depreciation of material properties that occurs during thermal-mechanical processing. These rejects are generally deposited in land wastes. In this work was carried out a study about recycling of PET wastes from NWF production lines, using additives of chain extender kind to recoup properties that had been highly depreciated. The incorporation of chain extenders of kind anhydride, isocyanate and phosphorous compounds by reactive extrusion improved considerably some chemical, mechanical and rheological properties of PET waste such as increase in molecular weight, melt viscosity and strain strength, easing the thermal-mechanical processing and making possible the use of PET waste in news steps of mechanical recycling. The possibility to convert expenditures with wastes discarding operations into profits due to the values aggregation on these polymeric wastes is very interesting for the industries. Then, the decrease of amount of polymeric materials deposited in natural environment signifies less contamination to several ecosystems, supporting the works that have been realized to decrease pollutants and to preserve the nature.
4

Studies on Reactive Blends of Poly (hydroxybutyrate-co-valerate) and Poly (butylene succinate) Bioplastics

Praphulla, Praphulla, Praphulla, Praphulla 12 December 2012 (has links)
Various commodity plastics used today are based on fossil fuels. Most of these plastics are non-biodegradable and will persist in the environment over a long time. The bioplastics from renewable resources have the potential to support a greener economy. The two of such renewably resourced bioplastics are poly (hydroxyl butyrate-co-valerate), PHBV and poly (butylene succinate), PBS. We have used petro-based PBS in our study, but renewable resource based PBS is expected to be available on a commercial scale in a very near future. These two bioplastics are both biodegradable. These two bioplastics are both biodegradable. In our study we have used PBS from petroleum resource but PHBV is a brittle bioplastic with a high modulus value and a low elongation at break while PBS is a low modulus bioplastic with a high elongation at break. Complementary properties can be obtained by blending PHBV and PBS. The direct melt blends showed poor mechanical properties due to limited interaction between PHBV and PBS phases. This research focuses on increasing the interaction between PHBV and PBS blends by using compatibilizers. The compatibilizers used in this thesis were dicumyl peroxide, DCP and trimethylolpropane triacrylate, TMPTA. Use of an in situ compatibilization method was done for the melt mixing of PHBV and PBS yielding blends with improved characteristics. The investigations were performed at three different ratios of PHBV and PBS blends. The increase in the compatibility between the two phases was demonstrated through various thermal, thermo-mechanical, rheological and morphological means. The increase in elongation at break was used as a primary marker for compatibilization. The optimization of DCP and TMPTA was carried out, which showed the enhanced interaction between PHBV and PBS phases, with the successful stress transfer from PHBV phase to the PBS phase resulting in increase in elongation at break. Inward shifts in tan delta peak on addition of DCP and TMPTA to the blends also showed increase in compatibility between the two phases. The interfacial adhesion between a brittle and ductile polymer, PHBV and PBS respectively was increased by using DCP and TMPTA. This opened gateways to various novel applications of PHBV and PBS blends via in situ reactive extrusion process. / The Ontario Ministry of Agriculture, Food, and Rural Affairs (OMAFRA) for their financial support via New directions research program (SR9235). We would also like to thank Canadian Foundation for Innovation (CFI) and Ontario Ministry of Agriculture, Food, and Rural Affairs (OMAFRA) for their equipment supports.
5

Funkcionalizace polypropylenu maleimidy / Functionalization of Polypropylene by Maleimides

Korčušková, Martina January 2020 (has links)
Diploma thesis deals with preparation of polypropylene functionalized by maleimides, based on the reaction between maleic anhydride and amine. The overview of functionalization of polypropylene by maleic anhydride by reactive extrusion and routes for the synthesis and utilization of maleimides are contained in the theoretical part. Samples of maleimide-functionalized polypropylene were prepared by reactive extrusion using low molecular weight amines (aniline and 4-aminophenol) and hight molecular weight polyether monoamines. Functionalized polypropylene samples were prepared by several methods differing in the composition of the reaction mixture and performing a grafting reaction. Appropriate maleamic acids and maleimides were synthesized from low molecular weight amines and further used to functionalize the polypropylene. To characterize the samples, the degree of monomer conversion and melt flow index were determined and further analyses were performed by Fourier transform infrared spectroscopy, differential scanning calorimetry and thermogravimetric analysis. The synthesis of low molecular weight products was further monitored by thin layer chromatography and thermogravimetric analysis with evolved gas analysis.
6

Procédés d'extrusion réactive et de mélange de polymères : synthèse contrôlée de copolymères greffés à base de polystyrène et de polyamide : et étude de l'efficacité de compatibilisation de ces copolymères / Réactive and polymer blending process : controlled synthesis of polystyrene and polyamide graft copolymers and compatibilizing efficiency of these copolymers

Zhang, Cai-Liang 10 November 2008 (has links)
Les mélanges de polymères ouvrent une importante voie à l’obtention de nouveaux matériaux dont les propriétés peuvent être très différentes de celles de chacun des constituants des mélanges. La plupart des polymères sont immiscibles. Ainsi leurs mélanges constituent des phases distinctes et les propriétés de ces mélanges sont souvent médiocres. Afin de relever ce défi, copolymères à bloc ou greffés synthétisés séparément ou générés in-situ lors du procédé de mélanges sont souvent utilisés en tant que agents compatibilisants. Beaucoup d’études ont porté sur l’efficacité de compatibilisation de copolymères à bloc et peu d’études sur celle de copolymères greffés, en partie en raison des difficultés dans le contrôle de leurs structures moléculaires. Cette thèse porte sur l’étude de l’efficacité d’émulsification de copolymères greffés. Elle est composée de trois parties : (1) développement d’un nouveau procédé d’extrusion réactive pour la synthèse de copolymères greffés avec polystyrène (PS) comme squelette et polyamide 6 (PA6) comme greffons ; (2) efficacité d’émulsification du copolymère greffé, PS-g-PA6 pour les mélanges à base de PS et PA6 ; et (3) développement d’un nouveau concept dit d’agent émulsifiant – traceur / Polymer blending offers an important route to new materials with combinations of properties not available in constituent polymers. Most polymer pairs are immiscible, leading to phase separation at equilibrium and yield a material with poor properties. To address this challenge, block or graft copolymers pre-made or generated in-situ by reactive blending are often used as compatibilizers. Most studies are focused on the compatibilizing efficiency of block copolymers and few studies address that of graft copolymers, partly because of difficulties of controlling their molecular structures.This thesis is devoted to the study of the emulsification efficiency of graft copolymers. It is composed of three parts: (1) development of a novel reactive extrusion process for synthesizing graft copolymers with polystyrene (PS) as backbone and polyamide 6 (PA6) as grafts; (2) emulsification efficiency of PS-g-PA6 graft copolymers for PS/PA6 blends; and (3) concept of emulsifier- tracer
7

Synthèse par extrusion réactive de polycondensats de polyamides / Synthesis by reactivie extrusion of polyamides polycondensates

Boissière, Jean-Marie 06 November 2008 (has links)
L'objectif de ce travail est d'étudier la faisabilité d'ajout de sel nylon à un polyamide (PA) par un procédé d’extrusion réactive. Dans ce cadre, l'ajout de sel 6T comprenant des motifs aromatiques à du PA 66 est réalisé dans le but de synthétiser du PA 66/6T. En effet, ce dernier répond à la demande actuelle en polymères à haute résistance thermique. Le taux d'avancement de la réaction et le taux de motifs 6T insérés doivent dès lors être maximisés.Le travail comprend les synthèses et les analyses du sel 6T, du PA 6T et du PA 66/6T. Le sel 6T est produit puisqu'il n'est pas commercialisé. Le PA 6T est synthétisé pour permettre l’identification des hydrogènes aromatiques du PA 66/6T. Le travail sur ce dernier nécessite la mise au point et l'étude du procédé d'extrusion. Pour ce faire, les influences d'un certain nombre de paramètres opératoires sont étudiées comme, par exemple, le niveau de vide sur les évents de l'extrudeuse.Les meilleures conditions opératoires du procédé permettent d’obtenir un taux d'avancement de 93 mol% et un taux d'insertion de motifs 6T de 15,3 mol%. Néanmoins, le PA 66/6T produit présente un fort excès de fonctions terminales acides / The aim of this work is to study the feasibility of addition of nylon salt to polyamide (PA) by a reactive extrusion process. As example, the addition of 6T salt, which includes aromatic monomers, to PA 66 is performed in order to synthesize PA 66/6T. This latter replies to demand of high resistance temperature polymer. Consequently, the progress rate of the reaction and the rate of 6T motifs insertion have to be maximized.This work includes the synthesis and the analysis of 6T salt, PA 6T and PA 66/6T. 6T salt synthesis is performed since it is not commercialised. PA 6T is synthesized in order to identify aromatic hydrogen in PA 66/6T molecule. About this latter, it is necessary to adjust and to study the extrusion process. So, the influences of few process parameters are studied as, for example, pressure level on vent gas of the extruder.With the best process parameters, the progress rate is 93 mol% and the rate of 6T motifs insertion is 15,3 mol%. Yet, PA 66/6T presents a significant excess of acidic end group
8

Starch crosslinking for cellulose fiber modification and starch nanoparticle formation

Song, Delong 23 March 2011 (has links)
As a low cost natural polymer, starch is widely used in paper, food, adhesive, and many other industries. In order to improve the performance of starch, crosslinking is often conducted either in the processes of starch modification or during the application processes. Many crosslinkers have been developed in the past for crosslinking starch. Ammonium zirconium carbonate (AZC) is one of the common crosslinkers for crosslinking starch in aqueous solutions, having been widely used as a starch crosslinking agent in paper surface coating for more than 20 years. However, the mechanisms of starch crosslinking with AZC have not been well studied. In order to optimize the crosslinking chemistry of starch and find new paths for the utilization of starch in papermaking, a better understanding of the starch crosslinking mechanism is necessary. This thesis focuses on the fundamental study of starch crosslinking in an aqueous solution and its applications in fiber surface grafting, filler modification, and starch nanoparticle formation. Particularly, the thesis contains three major parts: (1) Mechanism study of starch crosslinking induced by AZC: In this thesis, the crosslinking (or gelation) kinetics of starch/AZC blends were investigated by using rheological measurements. The evolution of viscoelastic properties of AZC solutions and the AZC-starch blends was characterized. It was found that for both AZC self-crosslinking and AZC-starch co-crosslinking, the initial bond formation rate and the gel strength had a strong power law relationship with the concentrations of both AZC and starch. It is suggested that the development of the crosslinking network is highly dependent on the AZC concentration, while the starch concentration effect is less significant. It was determined that the activation energy of AZC self-crosslinking was approximately 145-151 kJ/mol, while the activation energy of AZC-starch co-crosslinking was 139 kJ/mol. (2) Fiber and filler modifications with starch and crosslinkers: Besides reacting with starch, AZC can react with cellulose which also contains hydroxyl groups. Theoretically, it is possible to use AZC as a crosslinker / coupling agent to graft starch onto cellulose fibers. It is believed that the grafted starch on fiber surfaces can improve the fiber bonding capability. In this thesis, a facile method to graft starch onto cellulose fiber surfaces through the hydrogen bond formation among cellulose, starch and AZC was developed. Compared with the paper sheets made of fibers with an industry refining level (420 ml CSF), the paper sheets made of fibers with a much lower refining degree but with grafted starch showed higher paper strengths, including the tensile strength, stiffness and z direction tensile; meanwhile, a faster drainage rate during web formation could also be achieved. Not only can the fiber-fiber bonding be improved by grafting starch onto fiber surfaces, but the filler-fiber bonding can also be improved if starch can be effectively coated on the filler surface. This concept has been supported by the early studies. In this thesis, the effects of the crosslinking of starch in the filler modification for the papermaking application were also studied. (3) Mechanism of starch nanoparticle formation during extrusion with crosslinkers: It was reported that starch crosslinking could facilitate the reduction of starch particle size during reactive extrusion. However, the mechanism of the particle size reduction by starch crosslinking was not illustrated. The reason that the crosslinking can cause the particle size reduction of starch during extrusion is fundamentally interesting. In this thesis, the mechanism of starch particle size reduction during extrusion with and without crosslinkers was investigated by identifying the contributions of thermal and mechanical effects. The effects of extrusion conditions, including temperature, screw speed, torque, starch water content and crosslinker addition, on the particle size were studied. It was found that the addition of crosslinkers could significantly increase the shear force (torque), and consequently facilitate the reduction of the particle size. The results indicate that for extrusion without a crosslinker, the starch particle size decreased with the increase of temperature. At 100 degree Celsius, the starch particles with a size of 300 nm could be obtained. With the addition of appropriate crosslinkers (glyoxal), the starch particle size could be reduced to around 160 nm, even at a lower extrusion temperature of 75 degree Celsius .
9

Graftização de anidrido maleico em polipropileno, por extrusão reativa, na presença de nanopartículas: estudo de reação e monitoramento in-line

Muñoz, Pablo Andrés Riveros 17 April 2014 (has links)
Made available in DSpace on 2016-06-02T19:10:21Z (GMT). No. of bitstreams: 1 5915.pdf: 3044014 bytes, checksum: 6a376f2e7b858f324320d8e103c124a2 (MD5) Previous issue date: 2014-04-17 / Universidade Federal de Sao Carlos / The grafting reaction of maleic anhydride onto polypropylene by reactive extrusion, in presence of nanoclay, was studied. The organoclay (Cloisite 20A) was used as support for dicumyl peroxide (DCP), and different amounts of clay were used. The increment in the clay amount leads to reduction in the reaction rates, because it hinders the peroxide release, once organoclay absorbs partially the peroxide. Changes in the reaction mechanisms, in presence and absence of clay, were performed in a Haake internal mixing chamber, between 1 and 7 min of reaction. The results showed changes in the number, and length of maleic anhydride grafting, and in the molar mass. The reactive extrusion of polypropylene with maleic anhydride was studied based in central composite experimental design, using as factors the maleic anhydride and dicumyl peroxide concentrations. The experimental design was analyzed by ANOVA and shows that the increment in clay, used as peroxide support, leads to decrease in the grafting reaction of short succinic groups, by the introduction of long succinic groups, because its concentration increases the maleic anhydride homopolymerization. In the same way the increase in maleic anhydride concentration leads to decrease in the PP grafting level, because the maleic anhydride homopolimerization is increased, decreasing the reaction between polymer and monomer. The in-line monitoring of the reactive extrusion showed a good correlation between the light absorption measured and the formation of secondary reaction products, lately identified off-line as poli(maleic anhydride). / Neste trabalho estudou-se a reação de graftização de anidrido maleico em polipropileno, por extrusão reativa, na presença de nanopartículas argila montmorilonita. A argila montmorilonita organicamente modificada (Cloisite 20A) foi utilizada como suporte para o peróxido de dicumila (DCP), e foi testada em diferentes proporções. Este estudo mostrou que a argila é capaz de absorver parcialmente o peróxido, e que a quantidade de peróxido absorvida interfere no rendimento das reações. As alterações no mecanismo de reação, induzidas pela presença de argila, foram inicialmente estudadas em câmara de mistura Haake, sendo que a reação, na presença e ausência da argila, foi realizada entre 1 e 7min. Os resultados indicam alterações no tamanho e número de enxertias, além de alterações na degradação das cadeias poliméricas, estudadas através de SEC. Já a extrusão reativa do polipropileno com anidrido maleico, foi estudada com base em um planejamento experimental tipo composto central, onde os fatores estudados foram as concentrações de anidrido maleico e peróxido. A análise do planejamento experimental, realizada por ANOVA, mostra que a presença da argila, utilizada como suporte para o peróxido, tende a diminuir a quantidade de enxertias succínicas curtas, favorecendo a inserção de enxertias succínicas longas, devido à maior incidência das reações de homopolimerização do anidrido maleico. De maneira análoga o aumento nas concentrações de anidrido maleico, diminui o nível de reação, pois há maior concorrência entre as reações de graftização e homopolimerização do monômero. O monitoramento em tempo real das extrusões, mostrou a possibilidade de quantificação da modificação química por meio de colorimetria in-line, através do monitoramento da formação de produtos secundários, identificados como poli(anidrido maleico).
10

Élaboration des plaques en mousses de calage issues d’agroressources par extrusion réactive. Optimisation des relations Process-structures-propriétés / Elaboration of foam cushions from agroresources by reactive extrusion. Optimization of the Process-structures-properties

Abinader, Georges 04 December 2014 (has links)
Les mousses de calage en plastique utilisées dans les emballages sont très volumineuses et beaucoup de travaux s'intéressent à limiter leur production et à les remplacer par des matériaux qui soient biosourcés et/ou compostables mais avec des propriétés mécaniques comparables aux mousses en plastique pétrochimique. Ainsi vient l'idée de ce projet de recherche qui consiste à développer des mousses de calage à base d'amidon par extrusion réactive, en étudiant les relations : formulation – process – structure – propriétés. L'un des objectifs de ce travail de recherche est de comprendre et d'optimiser le procédé de fabrication des plaques de mousses de calage à base d'amidon afin d'assurer la stabilité et la reproductibilité du procédé. Dans le cadre de cette étude, nous avons déterminé la combinaison idéale « procédé/matière » en étudiant l'effet des différents ingrédients de la formulation sur les propriétés mécaniques et structurales des mousses résultantes. Les mousses ayant obtenu les meilleures propriétés de calage ont été caractérisées et leurs performances mécaniques, en termes d'absorption, d'amortissement et de transmission du choc lors du transport, ont été comparées à celles des mousses de calage traditionnelles d'origine pétrochimique. Nous avons également étudié le vieillissement, la biodégradabilité et la stabilité des propriétés des mousses à différentes conditions climatiques. Ces études nous ont permis de déterminer la stabilité des mousses dans le temps et leur comportement selon que l'on soit dans une région tempérée, tropicale ou autres. Dans le but d'améliorer les propriétés et les performances mécaniques des mousses et de réduire leur sensibilité à l'humidité, nous avons rajouté des fibres naturelles, des biopolymères et des charges minérales à la formulation de base et étudié leurs effets sur les propriétés des mousses résultantes. Le développement des mousses à base d'amidon par extrusion réactive a alors été optimisé. Les mousses extrudées ont obtenu des propriétés physiques et un pouvoir amortissant comparables aux mousses en plastique traditionnelles, type polyéthylène expansé, leur permettant d'être utilisées dans diverses applications dont principalement les calages qui, à l'issu de ces travaux de recherche, va être développé à l'échelle industrielle. / Foam cushions used in packaging are very light and bulky and a lot of efforts have been made to limit their production and to replace them with materials that are from renewable resources but with comparable mechanical properties to the current petroleum plastic foams. Consequently, the aim of this project, which consists of developing starch-based foam cushions by reactive extrusion, is to study the relationship between formulation, process, structure and properties. One of the research goals was to understand and optimize the manufacturing process of starch-based foam sheets to ensure the stability and the repeatability of the process. In this study, we determined the perfect « process / material » combination by studying the effects of the various ingredients of the formulation on the mechanical and structural properties of the resulting foams. The foams with the best cushioning properties were characterized and their mechanical performances in terms of absorption, cushioning and shock transmission during transport were compared to those of petrochemical foam cushions. We also studied the aging, biodegradability and stability of the foam properties at different climatic conditions. These studies allowed us to determine the long-term stability of the material and their behavior depending on their storage conditions. In order to improve the mechanical properties of the foams and to reduce their moisture sensitivity, we added natural fibers, mineral fillers and biopolymers to the formulation and studied their effects on the resulting properties. Thus, the development of starch-based foams by reactive extrusion has been optimized. The extruded foams have comparable physical properties with the conventional plastic foams, like expanded polyethylene, allowing them to be used in various applications, especially as cushioning materials, which is now ready to be developed at industrial scale.

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