Co-intercalation in PP clay nanocomposites : effect of short chain additives on rheological properties / B. Haworth in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 1 (03/2011)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVI, N° 1 (03/2011) . - p. 91-99 Titre : Co-intercalation in PP clay nanocomposites : effect of short chain additives on rheological properties Type de document : texte imprimé Auteurs : B. Haworth, Auteur ; U. N. Ratnayake, Auteur Année de publication : 2011 Article en page(s) : p. 91-99 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Argile Dispersions et suspensions Ecoulement cisaillé Matériaux hybrides Montmorillonite Polymères -- Additifs Polypropylène Index. décimale : 668.9 Polymères Résumé : Layered structures in inorganic minerals are not easily intercalated when combined with conventional non-polar polymers such as polypropylene (PP). A new co-intercalation method is reported whereby the combined influence of low molecular weight polar additives and polyolefin-based compatibilizers on PP-clay nanocomposites (PPCN) has been investigated. Our research has shown that the interlayer spacing of montmorillonite clay increases dramatically, and increased particle dispersion is achieved, when short chain, organic additives (typically amidetype, AM) are included. In this work, the migration of these additives into the clay galleries has been confirmed by surface energy data (from contact angle experiments) and by various capillary flow measurement techniques. Shear flow data have been used to interpret the mechanism of intercalation, following compound preparation using melt-state mixing processes. At relatively low concentrations, the erucamide molecules assist the intercalation process in nanocomposites; however if an excess of AM is apparent within the bulk polymer melt, unusual flow behavior is observed which can be attributed to wall slip. Modified melt elasticity is also obtained with the PPCN’s leading to reduced die swell characteristics in extrusion processes. Significant differences in melt flow behavior can therefore be attributed to the presence of AM; a mechanism for co-intercalation has been proposed in terms of hydrogen bonding between the additives and the silicate layers. DOI : 10.3139/217.2409 En ligne : https://drive.google.com/file/d/18BmekobMvn91EwgaGdQg2f9tWakUkZcW/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=11068 [article]

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The influence of different melt temperatures on the mechanical properties of injection molded PA-12 and the post process detection by thermal analysis / T. Meyer in INTERNATIONAL POLYMER PROCESSING, Vol. XXXII, N° 1 (03/2017)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXXII, N° 1 (03/2017) . - p. 90-101 Titre : The influence of different melt temperatures on the mechanical properties of injection molded PA-12 and the post process detection by thermal analysis Type de document : texte imprimé Auteurs : T. Meyer, Auteur ; A. Harland, Auteur ; B. Haworth, Auteur ; C. Holmes, Auteur ; T. Lucas, Auteur ; P. Sherratt, Auteur Année de publication : 2017 Article en page(s) : p. 90-101 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse des défaillances (fiabilité) Analyse thermique Essais de résilience Essais dynamiques Matières plastiques -- Moulage par injection Polyamide 12 Polymères -- Effets de la température Polymères -- Fusion Traction (mécanique) Index. décimale : 668.4 Plastiques, vinyles Résumé : Polyamide 12 (PA-12) test plates were injection molded using different melt temperatures and the influence on mechanical properties was investigated using quasi-static tensile and instrumented impact behavior in two conditioned states: dried, and following accelerated moisture intake. Energy absorption in tension is strongly dependent on process temperature (variations up to 99%) and additional variation (around 18%) was evident when testing at different conditioning states. Under high-velocity loading, the total impact energy varied by up to 8.70% and 9.05%, when systematic changes were made to process melt temperature and at moisture content, respectively, with all samples failing ductile. Differential Scanning Calorimetry (DSC) was used to characterise the unique endothermic melting behavior of molded PA-12 samples, by linking different process histories to the respective mechanical properties. With focus on the first heating curve progression, significant changes within the endothermic melting region were pointed out and quantified by using MatLab (software), proving DSC as a reliable testing tool for post-production analysis with increased practical implications regarding quality control as well as failure analysis. Findings for the initial heating curve progression were explained by studying the re-crystallisation peak values during cooling phase and obtained data for the second heating. Note de contenu : - INTRODUCTION AND RESEARCH OBJECTIVES - EXPERIMENTAL : Materials and injection molding - Sample preparation and conditioning - Quasi-static tensile testing - Instrumented falling weight impact testing - Analysis using differential scanning calorimetry (DSC) - Data processing - RESULTS AND DISCUSSION : Observation from processing - Influence on tensile behavior - Process influence on impact behavior - Differential scanning calorimetry DOI : 10.3139/217.3288 En ligne : https://drive.google.com/file/d/1t074OZbPAAbUIzy7Or3x3eDYGxl6dsd1/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=28005 [article]

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