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Fibre orientation in injection moulded compositesBubb, Simon Lawrence January 1988 (has links)
No description available.
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The effects of tool geometry and process conditions on stereolithography tooling performanceBrown, Stuart January 2004 (has links)
No description available.
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Investigation of lthe mechanical properties of injection moulded parts produced with rapid toolingSegal, Joel January 2004 (has links)
No description available.
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Reducing cycle times in rotational moulding of plastics : a theoretical and experimental analysisKhouri, R. M. January 2004 (has links)
No description available.
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Sandwich injection moulding with thermoset materialsKiatmanaroj, Subongkoj January 2004 (has links)
This project aimed to study the feasibility of making a thermoset sandwich injection moulding from a novel thermoset co-injection moulding system. Two thermoset polyesters, BMC and a powder coating, were used for all experiments. Flow and cure of those materials in a newly designed manifold system were studied and some thermoset sandwich injection mouldings have been produced. Despite producing novel co-injection mouldings using two thermoset materials together, the results showed that the existing system was not applicable for large-scale production of sandwich parts and needed some improvements. The experiments on the moulding materials and single injection of each material gave temperature windows and settings for the co-injection moulding. The results from all experiments indicated that temperature and the time of applying heat to a thermoset material were very important to its flow ability and formation. Especially when producing a sandwich moulding, adequate heat and time was necessary for the skin material to form a sufficient layer to cover the core material. Investigation of the sandwich moulding cross-sections showed that applying more core injection delay time could help to increase the skin thickness. Surface assessmenitn dicated that the surface quality was also improved when the skin layer was thicker. However, core break-through at the position opposite to the mould gate was found in all sandwich mouldings showing that the type of mould gate was also important. A central sprue gated mould used in these experiments was found to be not suitable for producing a sandwich component using this machine configuration. A new manifold design was proposed and was compared to the existing manifold designed by using a simulation software package from Moldflow. Thermoset single injection moulding simulation was used to help to understand the flow and cure of a thermoset material in both manifold designs. It was shown that the new manifold system design was an improvement on the existing one.
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Elaboration et mise en forme de matériaux polymères à base de l’ε-caprolactame (PA6) par le procédé de rotomoulage réactif / Synthesis and processing of polymeric materials based on the ε-caprolactam (PA6) by reactive rotational molding processBarhoumi, Najoua 09 December 2013 (has links)
Cette thèse porte sur le rotomoulage réactif de polyamide 6. Ce procédé a la particularité de présenter des cycles thermiques relativement réduit et de fabriquer des polymères sur mesure contrairement à son homologue conventionnelle. La voie envisagée pour la synthèse in situ de PA6 est la polymérisation anionique de l’ε-caprolactame par ouverture de cycle. Le Caprolactamate de sodium et le bromure de caprolactame-magnésium ont été utilisés comme catalyseurs, et l’hexaméthylène dicarbamoyl dicaprolactame a été employé comme activateur. L’étude rhéocinétique de deux systèmes réactifs lactames qui ont été utilisé à différentes compositions et températures a permis de déterminer une formulation appropriée aux exigences du procédé (faible viscosité initiale du système réactif, temps de polymérisation court...). La simultanéité des phénomènes de polymérisation et de cristallisation aux faibles températures à été observé à l’aide des résultats du suivi cinétique par DSC. La mise en forme par la technique de rotomoulage a été réalisée sur une installation pilote de rotomoulage associée à un système d’acquisition de température par télémesure radio. La comparaison des propriétés des articles en PA 6 obtenus par voie réactive par rapport a ceux obtenus par voie fondue, a montré un gain au niveau du temps de cycle et une amélioration des propriétés mécaniques du matériau notamment dans le domaine des faibles déformations. Le rotomoulage de la bicouche PA6/PE-GMA a été ainsi étudié, le contrôle des mécanismes réactionnels mis en jeu à l’interface par rhéologie, durant la formation de la couche de polymère PA6 par voie anionique sur une couche de PE-GMA a été effectué dans un rhéomètre, une bonne adhésion à l’interface a été observé. La faisabilité d’élaboration de nanocomposite PA 6/argile par le procède de rotomoulage réactif a été testé, les caractérisations physico-chimiques et les observations morphologiques ont été étudiés afin d’évaluer l’état de dispersion et la nature des interactions. Durant cette étude, nous avons mesurés la faisabilité de l’intercalation et le gonflement de l’argile dans le monomère ε- caprolactame et estimer la possibilité d’avoir une morphologie exfolié des nanocomposites élaborés par le procédé de rotomoulage réactif. / A reactive rotational molding (RRM) process was developed to obtain a PA6 by activated anionic ring-opening polymerization of epsilon-caprolactam (APA6). Sodium caprolactamate (C10) and caprolactam magnesium bromide (C1) were employed as catalysts, and difunctional hexamethylene-1,6-dicarbamoylcaprolactam (C20) was used as an activator. The kinetics of the anionic polymerization of ε-caprolactam into polyamide 6 was monitored through dynamic rheology and differential scanning calorimetry measurements. The effect of the processing parameters, such as the polymerization temperature, different catalyst/activator combinations and concentrations, on the kinetics of polymerization is discussed. A temperature of 150°C was demonstrated to be the most appropriate. It was also found that crystallization may occur during PA6 polymerization and that the combination C1/C20 was well suited as it permitted a suitable induction time. Isoviscosity curves were drawn in order to determine the available processing window for RRM. The properties of the obtained APA6 were compared with those of a conventionally rotomolded PA6. Results pointed at lower cycle times and increased tensile properties at weak deformation. Additionally, rotational molding of the bilayer PA6/PE-GMA has been studied, the control of the reactions mechanisms involved in the interface by rheology , during formation of the anionically PA6 polymer layer on a PE- GMA layer was carried out in a rheometer , a good adhesion at the interface was observed. The feasibility of developing nanocomposite PA 6/clay by reactive rotational molding process has been tested; the physico-chemical characterization and morphological observations were studied to assess the state of dispersion and the nature of interactions. During this study, we measured the feasibility of intercalation and swelling the clay in the ε-caprolactam monomer and estimate the possibility of having morphology of exfoliated nanocomposites prepared by reactive rotational molding process.
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