Effect of blend ratio of h-LLDPE and LDPE on tear properties of blown films / K. Mezghani in INTERNATIONAL POLYMER PROCESSING, Vol. XXVII, N° 3 (07/2012)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVII, N° 3 (07/2012) . - p. 392-398 Titre : Effect of blend ratio of h-LLDPE and LDPE on tear properties of blown films Type de document : texte imprimé Auteurs : K. Mezghani, Auteur ; S. Furquan, Auteur ; S. H. Tabatabaei, Auteur ; Abdellah Ajji, Auteur Année de publication : 2012 Article en page(s) : p. 392-398 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Alliages polymères Déchirure (mécanique) Films plastiques Matières plastiques -- Moulage par soufflage Polyéthylène basse densité Polyéthylène basse densité linéaire Index. décimale : 668.4 Plastiques, vinyles Résumé : In the present study, blown films of h-LLDPE, LDPE, and their blends were produced using a twin screw extruder. The tear properties of all films were determined in the machine direction (MD) and the transverse direction (TD). On one hand, similar values of the MD tear-resistance for the two virgin polymers, h-LLDPE and LDPE, were measured to be 100 and 120 kN/m, respectively. On the other hand, the TD tear-resistance value of h-LLDPE was 180 kN/m, four times higher than that of LDPE, 45 kN/m. It was observed that small additions of LDPE (5 to 20 wt.%) to h-LLDPE produced blends with better TD tear-resistance films, 400 kN/m. The main reason for this large increase in tear-resistance was attributed to the morphological changes induced by the addition of the LDPE polymer, as shown by SEM, FTIR, and birefringence techniques. DOI : 10.3139/217.2575 En ligne : https://drive.google.com/file/d/1km2DyzdXrFH3k6gKeOEgrvsq7BwUy_AH/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15586 [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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Enhancement of heat seal properties of polypropylene films by elastomer incorporation / R. Boutrouka in INTERNATIONAL POLYMER PROCESSING, Vol. XXXIII, N° 3 (07/2018)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXXIII, N° 3 (07/2018) . - p. 322-326 Titre : Enhancement of heat seal properties of polypropylene films by elastomer incorporation Type de document : texte imprimé Auteurs : R. Boutrouka, Auteur ; S. H. Tabatabaei, Auteur ; Abdellah Ajji, Auteur Année de publication : 2018 Article en page(s) : p. 322-326 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse thermique Copolymères Elastomères Films plastiques Matières plastiques -- Extrusion Matières plastiques -- Soudage Polypropylène Index. décimale : 668.4 Plastiques, vinyles Résumé : Seal strength at high and low temperatures as well as the width of the heat sealing temperature range are important properties in packaging industry. In addition, for sterilisable and retort applications, having those properties at elevated temperatures is crucial. Polypropylenes (PP) are usually used for these applications, however, the sealing temperatures are too high and the temperature range for the seal process is narrow, thus blending with a PP elastomer copolymer can be an alternative. In this study, hot-tack and heat seal properties were determined for a homo-polypropylene, a random co-polypropylene and an elastomer co-polypropylene based films and their blends. It is found that the seal initiation temperature (for hot tack and heat seal) is governed by the melting temperature and crystallinity and the increase of the elastomer content in the blends leads to a decrease of the seal initiation temperature. It is also shown that the sealing force depends on the ease of chains diffusion across the sealing interface. Finally, it was found that the strength of the heat sealing increases by recrystallization in the sealing interface after cooling. Note de contenu : - EXPERIMENTAL : Materials - Films co-extrusion - Thermal analysis - Heat seal testing - RESULTS AND DISCUSSION : Hot-tack DOI : 10.3139/217.3523 En ligne : https://drive.google.com/file/d/1goIWee-_8-72Jgs3Xvtxy62g1OyWcYg3/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=30800 [article]

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