Innovative materials for novel concepts for internal heat exchangers / Annette Rüppel in INTERNATIONAL POLYMER PROCESSING, Vol. XXXIII, N° 4 (08/2018)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXXIII, N° 4 (08/2018) . - p. 423-459 Titre : Innovative materials for novel concepts for internal heat exchangers Type de document : texte imprimé Auteurs : Annette Rüppel, Auteur ; D. Jähnig, Auteur ; R.-U. Giesen ; K. Vajen ; Hans-Peter Heim Année de publication : 2018 Article en page(s) : p. 423-459 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Charges (matériaux) Echangeur de chaleur interne Elastomères thermoplastiques Graphite Matières plastiques -- Extrusion Nitrure de bore Le nitrure de bore est un composé chimique du bore et de l'azote, de formule chimique brute BN (nombre égal d'atomes de chaque élément). Le nitrure de bore est isoélectronique avec le carbone et, comme ce dernier, existe sous plusieurs formes polymorphiques, dont l'une est analogue au diamant et l'autre au graphite. La forme diamant est l'un des matériaux les plus durs connus et la forme graphite est un lubrifiant apprécié. De plus, ces deux polymorphes possèdent des propriétés d'absorption radar. Polyéthylène à résistance thermique renforcée Polypropylène Thermocinétique Index. décimale : 668.4 Plastiques, vinyles Résumé : Internal heat exchangers are often employed in solar thermal applications as well as in many other applications that involve heat, and, for the most part, consist of metallic materials (copper, stainless steel). Corrugated stainless steel tubes are easy to assemble, and are commonly used in various storage geometries. In order to significantly reduce costs, alternative materials, such as plastics, can function as excellent substitutes. Alternative heat exchangers for the following examinations using various materials and an extrusion process were produced. Subsequently, the heat exchangers were examined in regards to the heat they transfer. The heat transfer coefficient and the thermal conductivity of all materials were determined. Note de contenu : - Alternative heat exchanger concepts - Experimental details - Examination of the thermal conductivity λ - Table 1 : Employed materials, modified for thermal conductivity - Table 2 : Thermal conductivity capacity results of all examined samples - Table 3 : Comparison of thermal conductivity capacities determined based on the temperature conductivity and heat transfer measurements DOI : 10.3139/217.3432 En ligne : https://www.degruyter.com/document/doi/10.3139/217.3432/pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=30884 [article]

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Mechanical properties of polydimethylsiloxane as a function of the amount and type of crosslinking agent / Fabian Verheyen in INTERNATIONAL POLYMER PROCESSING, Vol. XXXII, N° 3 (07/2017)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXXII, N° 3 (07/2017) . - p. 337-342 Titre : Mechanical properties of polydimethylsiloxane as a function of the amount and type of crosslinking agent Type de document : texte imprimé Auteurs : Fabian Verheyen, Auteur ; R.-U. Giesen, Auteur ; Hans-Peter Heim, Auteur Année de publication : 2017 Article en page(s) : p. 337-342 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Elastomères -- Propriétés mécaniques Elastomères silicones vulcanisables à chaud Essais dynamiques Polydiméthylsiloxane Le polydiméthylsiloxane —[O-Si(CH3)2]n—, ou poly(diméthylsiloxane) selon la nomenclature systématique, communément appelé PDMS ou diméthicone, est un polymère organominéral de la famille des siloxanes souvent présent dans les shampoings. On l'y ajoute pour augmenter le volume des cheveux mais il peut également aller boucher les pores du cuir chevelu et rendre les cheveux gras. C'est une des raisons pour lesquelles se laver les cheveux tous les jours est très déconseillé avec un shampooing contenant des silicones. Il existe également de l'amodiméthicone, qui est un dérivé du diméthicone. Le polydiméthylsiloxane est un additif alimentaire (E900), utilisé comme antimoussant dans les boissons (Coca-Cola BlāK). La chaîne de poly(diméthylsiloxane) forme également la structure de base des huiles et des caoutchoucs silicones. Réticulants Index. décimale : 668.4 Plastiques, vinyles Résumé : In this investigation, a high-consistency rubber (HCR) was mixed with five different, typically used crosslinking agents that are based on organic peroxide. Furthermore, the amount of crosslinking agent was varied in order to quantify the effect on the mechanical properties. All materials were processed in a hot pressing process, and, subsequently, post-cured. The properties were characterized by the measurement of the swelling ratio, shore A-hardness, rebound resilience and tensile test. We successfully proved that the swelling ratio is a suitable indicator for the evaluation of the crosslinking density of silicone rubber. The results show that the crosslinking density increases as the amount of crosslinking agent increases. The hardness, rebound resilience, and stress at 100% elongation increase as the crosslinking agent does. In contrast, the ultimate elongation decreases as the crosslinking density rises. The absolute values depend on the type of crosslinking agent used. The most commonly used crosslinking agent for high-consistency rubber is Di(2.4-dichlorobenzoyl) peroxide. We were able to verify that there are more possible curing agents based on organic peroxides on the market. Depending on the required properties, customized silicone elastomers could be easily produced. Note de contenu : - EXPERIMENTAL : Materials - Preparation - Characterisation - RESULTS AND DISCUSSION : Outward appearance - Swelling ratio - Shore A hardness - Rebound resilience - Tensile test DOI : 10.3139/217.3334 En ligne : https://drive.google.com/file/d/1QfSXE2AqFSi_9Pn3KZb2c75t5mJtOd_E/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=28835 [article]

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UV-pre-treatment for polycarbonate for bonding LSR in a multi-component injection molding process / Christof Ulrich Schlitt in INTERNATIONAL POLYMER PROCESSING, Vol. XXXIV, N° 1 (03/2019)

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXXIV, N° 1 (03/2019) . - p. 30-36 Titre : UV-pre-treatment for polycarbonate for bonding LSR in a multi-component injection molding process Type de document : texte imprimé Auteurs : Christof Ulrich Schlitt, Auteur ; M. Hartung, Auteur ; A. Rüppel, Auteur ; R.-U. Giesen, Auteur ; Hans-Peter Heim, Auteur Année de publication : 2019 Article en page(s) : p. 30-36 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Angle de contact Collage Energie de surface Essais de pelage Matières plastiques -- Moulage par injection multicomposant Ozone Polycarbonates Rayonnement ultraviolet Index. décimale : 668.4 Plastiques, vinyles Résumé : In this study, the influence of UVC radiation and the influence of ozone on the surface energy of specimens made of polycarbonate were investigated. In an additional step, the peeling resistance of silicone flaps, which were overmolded, onto pre-treated PC plates of multicomponent specimens were analyzed. For this purpose, the samples were exposed to UVC radiation for different lengths of time, ranging from 5 s to 3 600 s. To further evaluate the influence of the ozone created by the UVC in the presence of oxygen, treatments were also performed in pure oxygen and nitrogen atmospheres. Contact angle measurements as well as analyses of the surface roughness were carried out to evaluate the effect of the treatment. Two phenomena were identified during the investigations. In room air and oxygen atmospheres, a short-term effect of UVC radiation was observed, which led to an increase in the surface energy, and, therefore, also to an increase in the wettability after an exposure time of only 10 s. In addition, a long-term effect was also found when tests were performed in a nitrogen atmosphere. This effect became visible after at least 60 s, and increased over the course of the duration exposure. The surface roughness of the polycarbonate plates increased up to about 60 % after 10 s of UVC exposure time in an air atmosphere, after 300 s of exposure to UVC radiation the roughness values had more than doubled. A modular injection molding tool was designed for the production of multi-component specimens. In this tool, a thermoplastic plate is molded on the one side, and is then automatically transferred by a robot system to be overmolded with silicone on the other side. The employed injection molding technique makes an intermediate treatment, such as surface activation of the thermoplastic plate, possible before it is overmolded. Also, the short-term and long-term effects of UVC treatment were able to be verified again for the peeling resistance of the material. These tests were only carried out for specimens treated in air. Note de contenu : - OBJECTIVES - EXPERIMENTAL : Materials - UVC/ozone treatment - Test methods - Results and discussion : Contact angle and surface energy - Surface roughness - Peeling resistance of pre-treated multi-component specimens - Discussion DOI : 10.3139/217.3509 Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31909 [article]

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