Influence of chemical architecture of PET on ability to stretch blow moulding

International audiencePET specific properties make this material a good candidate for stretch blow moulding. However chemical architecture of the resin can be varied by the supplier. These changes induce different draw abilities or different behaviours whilst blowing. In this study some well controlled PET resins are characterized both from the point of view of their intrinsic properties and from the point of view of their process abilities. Results enlighten clearly the tight correlation between the chemical structure and the behaviour of the polymer. Coupling effects between the structure, the laboratory properties and the process ability exist making this process a highly not intuitive processing. This study allows, in parallel, proposing a global approach to estimate blowing ability from laboratory analysis

Stretch-blow molding of PET copolymers - Influence of molecular architecture

International audienceThe purpose of the paper is to study the influence of molecular architecture of poly(ethylene terephthalate) (PET) on its ability to be processed by stretch-blow molding, which is not well documented in the literature. To evaluate this process ability, it proposes an original strategy combining laboratory analyses and experiments on a prototype machine. PET copolymers were prepared from three types of comonomers: diethylene glycol (DEG), isophthalic acid (IPA) and trimethylolpropane (TMP). It is first shown, through laboratory experiments, that the nature of the polymer in terms of chain constitution (copolymerization), chain length (intrinsic viscosity) and purity (catalytic residues) greatly affects many properties: melt crystallization, thermal properties, polymer rigidity and drawability. These different properties obviously induce very different behaviours at the different steps of the stretch-blow molding process: injection-molding of the preform (quenchability), heating (IR absorption), stretch-blow (rigidity and drawability). The stretch-blow step has been simulated on a prototype apparatus designed in our laboratory. It has been shown that free blowing can be used to characterize the process ability of the polymer. A statistical analysis has confirmed the great differences between the materials investigated and pointed out the complexity of the material response during blowing

Les tubes hexagonaux de la génération IV

Pour répondre aux spécificités des RNR-Na de la Génération IV, les caractéristiques des TH ont évoluées depuis SUPERPHENIX. Les dimensions ont été augmentées et le matériau est choisi plus résistant mais moins déformable. La faisabilité industrielle de ces tubes est donc à vérifier, d'autant que la réglementation a évolué, limitant le recours à certains produits lubrifiants utilisés par le passé, et que les exigences en termes de qualité se sont accrues, rendant l'étape de transformation rond-hexagone encore plus délicate

Laminage de tubes ODS

Ce travail porte sur la mise en uvre de procédé de fabrication de tubes pour des nuances ODS par laminage à pas de pèlerin. Une première partie traitera de la détermination des lois de comportement et des paramètres adaptés pour étudier les nuances ODS dans les sollicitations liées au laminage. Ensuite on montrera la modélisation éléments finis d'une machine de laboratoire de type HPTR avant d'étendre les méthodologies de simulation au dispositif industriel qui est un laminoir VMR

Effet de l'architecture de chaîne sur le comportement en injection soufflage de copolyesters PET. - Etude expérimentale

Polyethylene terephthalate, or PET, is mainly used to produce bottles, generally by injection blowing. Inthis study, we point out, for each step of this process, differences of behaviour between severalcopolyesters having a controlled composition. Our attention focus principally on nature of introducedcomonomers, beyond ethylene glycol and terephthalic acid, and length of chains. Thus major solicitationssuffered by material during the bottle forming are reproduced by laboratory tests. We show that kinetic ofstatic crystallization, measured by DSC, could define cooling conditions to assure the amorphous natureof injected preforms. Moreover, blowing range, i.e. rubberized state, is obtained by DMA. Our resultsindicate too that it is necessary, to grasp behaviour during blowing, to consider a minimum of sixcharacteristics of polymer which could be temperature, elastic modulus, rate dependence of materialresponse, hardening strain and stress, and finally bi-axiality disequilibrium of hollow body forming. Lastlyit appears that material adapts its stress way to the solicitation according its rheology, which determinesbottle properties, notably in term of orientation or crystallisation.Le poly(éthylène téréphtalate), ou PET, est fortement présent dans le domaine du flaconnage où il estclassiquement mis en forme par injection soufflage. Dans cette étude, nous mettons en évidence, tout aulong de ce procédé, les différences de comportement qui existent entre des copolyesters de compositioncontrôlée. Notre attention porte principalement sur la nature des comonomères introduits, outre l'éthylèneglycol et l'acide téréphtalique, ainsi que sur la longueur des chaînes. De fait, les principales sollicitationssubies par la matière lors de la fabrication d'une bouteille sont reproduites par des essais de laboratoire.Nous montrons ainsi que la cinétique de cristallisation statique, accessible par DSC, permet de définir lesconditions de refroidissement assurant la nature amorphe des préformes injectées. De plus, la gamme desoufflage, i.e. l'état caoutchoutique, est déterminable par DMA. Nos résultats indiquent également qu'il estnécessaire, afin d'appréhender le comportement en soufflage, de tenir compte d'un minimum de sixcaractéristiques de la matière qui peuvent être la température, le module élastique, la dépendance en vitessede la réponse du matériau, les contrainte et déformation au durcissement, ainsi que le déséquilibre de la biaxialitéde la formation du corps creux. Finalement, il apparaît que le matériau adapte son chemin dedéformation à la sollicitation en fonction de sa rhéologie propre, ce qui n'est pas sans influence sur lespropriétés, en terme d'orientation ou de cristallisation, dans la bouteille

Impact of rolling conditions on the hydriding of grade 2 titanium welded tubes

In this article, we study the impact of rolling conditions on the texture of the commercially pure titanium grade 2. In a previous work, NEOTISS in collaboration with ICB laboratory, shown that the texture highly influences the precipitation of hydrides in Titanium. In order to create different textures, Titanium sheets grade 2 are cold rolled asymmetrically and symmetrically with or without lubricant. The inverse pole figures and direct pole figures obtained allow us to deduce that symmetrical cold rolling does not change the grains orientation but generates a rotation of grains along c-axis (normal to basal plan). However, asymmetrical cold rolling leads to the formation of a new crystallographic texture, which could limit the formation of the hydrides in titanium grade 2 submitted to a hydrogen-rich environment. Key words: asymmetrical rolling, symmetrical rolling, titanium, hydriding, textur

Impact of rolling conditions on the hydriding of grade 2 titanium welded tubes

In this article, we study the impact of rolling conditions on the texture of the commercially pure titanium grade 2. In a previous work, NEOTISS in collaboration with ICB laboratory, shown that the texture highly influences the precipitation of hydrides in Titanium. In order to create different textures, Titanium sheets grade 2 are cold rolled asymmetrically and symmetrically with or without lubricant. The inverse pole figures and direct pole figures obtained allow us to deduce that symmetrical cold rolling does not change the grains orientation but generates a rotation of grains along c-axis (normal to basal plan). However, asymmetrical cold rolling leads to the formation of a new crystallographic texture, which could limit the formation of the hydrides in titanium grade 2 submitted to a hydrogen-rich environment. Key words: asymmetrical rolling, symmetrical rolling, titanium, hydriding, textur

Starch based microparticles radiolabelling with 99mTc and 188Re for diagnostic and therapy of Hepatocellular carcinoma

International audienc

Starch based microparticles radiolabelling with 99mTc and 188Re for diagnostic and therapy of Hepatocellular carcinoma

International audienc