Effect of processing conditions on properties of PET/clay nanocomposite films / H. Ghasemi in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 2 (05/2011)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVI, N° 2 (05/2011) . - p. 219-228 Titre : Effect of processing conditions on properties of PET/clay nanocomposite films Type de document : texte imprimé Auteurs : H. Ghasemi, Auteur ; P. J. Carreau, Auteur ; Musa R. Kamal, Auteur ; N. Chapleau, Auteur Année de publication : 2011 Article en page(s) : p. 219-228 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Argile Cloisite Diffraction des rayons X à grand angle Diffractométrie de rayons X Films plastiques -- Propriétés mécaniques Matériaux hybrides Matériaux hybrides -- Propriétés mécaniques Matières plastiques -- Extrusion:Polymères -- Extrusion Microscopie électronique en transmission Polyéthylène téréphtalate Index. décimale : 668.9 Polymères Résumé : Polyethylene terephthalate (PET) nanocomposite films (with 3 wt.% Cloisite 30B) were prepared by cast extrusion followed by uniaxial stretching, using chill rolls. Two screw profiles with different mixing elements under different screw speeds (N) and feeding rates (Q) were used to prepare PET/clay nanocomposite (PCN) films. Transmission electron microscopy (TEM) and wide angle X-ray diffraction (WAXD) showed that the clay layers were aligned in the machine direction (MD). XRD patterns depicted that the interlayer distance of clay platelets in the state of intercalation is somehow independent of the processing conditions, but the macro-scale characterization, including barrier and mechanical properties, showed that the level of clay layer delamination was affected by processing conditions. The results reveal that the applied strain has stronger effect than residence time on the barrier and mechanical properties. At the highest screw speed (N = 250 min–1), 27% reduction in oxygen permeability and 30% improvement in tensile modulus were obtained for the more severe screw profile. DOI : 10.3139/217.2446 En ligne : https://drive.google.com/file/d/1CvQd5mAo3iMwpC48oYrC2pqX7YbvTjes/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=11526 [article]

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Effect of random and block copolypropylenes on structure and properties of uniaxially and biaxially oriented PP films / S. H. Tabatabaei in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 1 (03/2011)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVI, N° 1 (03/2011) . - p. 82-90 Titre : Effect of random and block copolypropylenes on structure and properties of uniaxially and biaxially oriented PP films Type de document : texte imprimé Auteurs : S. H. Tabatabaei, Auteur ; Abdellah Ajji, Auteur ; H. Ghasemi, Auteur Année de publication : 2011 Article en page(s) : p. 82-90 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse thermique Copolymères séquencés Films plastiques -- Propriétés mécaniques Microscopie en lumière polarisée Polypropylène Rhéologie Index. décimale : 668.9 Polymères Résumé : Cast films of two linear polypropylenes (PP) having different molecular weights and their blends with 5, 20, and 40 wt.% random and block copolymers were prepared. The produced cast films were uniaxially and biaxially hot drawn at T = 155ºC using a biaxial stretcher and the changes in structure and morphology were examined and related to barrier, mechanical, haze, and tear properties. The crystallinity and crystal size distribution of the films were studied using differential scanning calorimetry (DSC). The uniaxial drawing generated a highly oriented fibrillar structure, resulting in an increase in the melting point of the films. A significant effect of the random copolymer on the size of crystallites was found using DSC, which was also confirmed from polarized optical microscopy (POM). Compared to the neat homopolymers, finer and numerous spherulites were observed for the blends. During drawing, the applied loads in the machine and transverse directions (MD and TD, respectively) were recorded and related to breaking up and tilting of the crystal lamellae. Adding the random copolymer appreciably decreased the haze of the films and hence drastically improved the clarity. Tensile properties and tear resistance of the cast films in MD and TD were evaluated. The addition of the random copolymer slightly reduced the Young modulus and tensile strength, but increased the elongation at break. A slight increase in the oxygen transmission rate (OTR) of the biaxially drawn films were observed by adding the copolymer. DOI : 10.3139/217.2404 En ligne : https://drive.google.com/file/d/1Wu4KRz4nPjaAKjV4g9qq6NTTQtVcnsce/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=11053 [article]

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The effect of molecular parameters on the thermal behavior of recycled and virgin polyamides and their glass fiber composites / A. Mirzadeh in INTERNATIONAL POLYMER PROCESSING, Vol. XXIX, N° 1 (03/2014)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXIX, N° 1 (03/2014) . - p. 4-12 Titre : The effect of molecular parameters on the thermal behavior of recycled and virgin polyamides and their glass fiber composites Type de document : texte imprimé Auteurs : A. Mirzadeh, Auteur ; H. Ghasemi, Auteur ; Phil J. Bates, Auteur ; Musa R. Kamal, Auteur Année de publication : 2014 Article en page(s) : p. 4-12 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Composites à fibres de verre Composites à fibres de verre -- Recyclage Cristallisation Poids moléculaires Polyamide 6 Polyamide 66 Polymères -- Recyclage Produits et matériaux recyclés Structure moléculaire Index. décimale : 668.4 Plastiques, vinyles Résumé : A study was carried out to evaluate the effects of molecular weight and molecular structure on non-isothermal crystallization behavior of recycled and virgin polyamides (PA) and their corresponding glass fiber (GF) composites. Two different recycled polyamides (PA), namely post-industrial waste (PIW) and post-consumer waste (PCW) were used. The former was obtained from a fiber manufacturer and the latter was recycled from used carpets. The molecular weights of the resins were measured by intrinsic viscosity (IV) measurements and 13carbon nuclear magnetic resonance (13C-NMR). The NMR technique also provided information on PA structure, cis and trans amide conformers content and residual unreacted monomer. Non-isothermal crystallization of the resins was studied using differential scanning calorimetry (DSC). The molecular weights of recycled materials were higher than that of virgin injection molding grade PA-6. However, the crystallization rates (indicated by t1/2) of recycled resins were faster. It could be attributed to the presence of TiO2 in recycled materials. Moreover, the higher cis-amide conformer content of recycled resins suggested higher segmental mobility. On the other hand, the crystallization rate of composites based on recycled PA-6 was slower than that of composites based on the virgin PA-6. The suppression of crystallization rate was apparently due to PA-66 added during the preparation of reinforced recycled resins. This behavior was confirmed by model compounds based on PA-6/PA-66 blends. Note de contenu : - EXPERIMENTAL : Materials - Sample preparation and characterization - RESULTS AND DISCUSSION : Molecular weight measurements - Molecular parameters - Non-isothermal crystallization DOI : 10.3139/217.2775 En ligne : https://drive.google.com/file/d/1KHoV0g1ESFxZQ5ZDVRn6ufTY_hKn1AqA/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=20570 [article]

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