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Ajouter le résultat dans votre panierCrystallization and mechanical properties of poly(D, L)lactide-based blown films / G. Stoclet in INTERNATIONAL POLYMER PROCESSING, Vol. XXII, N° 5 (11/2007)
Titre : Crystallization and mechanical properties of poly(D, L)lactide-based blown films Type de document : texte imprimé Auteurs : G. Stoclet, Auteur ; J.-M. Lefebvre, Auteur ; R. Séguéla, Auteur ; V. Miri, Auteur ; S. Elkoun, Auteur Année de publication : 2007 Article en page(s) : p. 385-388 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : The crystallization, uniaxial and biaxial mechanical behavior of poly(D-, L-lactide)-based-blown films was investigated. It was shown that the selected grade of polylactic acid exhibits low isothermal and non-isothermal crystallization kinetics. In addition, the uniaxial stretching evidenced a ductile/fragile transition temperature located between 35 and 45°C. Eventually stress-induced crystallization was revealed upon uniaxial and simultaneous and sequential biaxial drawing. DOI : 10.3139/217.2066 En ligne : https://drive.google.com/file/d/1Wlp9RzXDIzJwKAV6kKvSjhRQ9zQxfUGg/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2678
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Titre : Rheological behavior and modeling of thermal degradation of poly(E-caprolactone) and poly(L-Lactide) Type de document : texte imprimé Auteurs : A. Lopez Arraiza, Auteur ; J. R. Sarasua, Auteur ; Jacques Verdu, Auteur ; Xavier Colin, Auteur Année de publication : 2007 Article en page(s) : p. 389-394 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Growing environmental concerns have led to the development of alternative biodegradable polymers with properties comparable to the conventional polyethylene, polypropylene or polyethylene terephthalate. In this paper the thermal degradation of poly(e-caprolactone) (PCL) and poly(L-lactide) (PLLA) melts was investigated by rheometry and thermogravimetry under different temperatures and inert atmosphere. The chain scission process was modeled to explain the phenomenon. The analysis suggests that PLLA is degraded by an unzipping depolymerization process from the hydroxyl end of the polymer chains. In contrast, the thermal degradation behavior of PCL was very complex because various reactions occurred concurrently : post-polymerization, loss of structural regularities and random chain scissions. DOI : 10.3139/217.2067 En ligne : https://drive.google.com/file/d/1Yc9ANakev3JVwPxoxCmIijo-XgtCzSQ1/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2679
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Titre : Rheological evaluation and observations of extrusion instabilities of biodegradable polyesters Type de document : texte imprimé Auteurs : D. Kanev, Auteur ; E. Takacs, Auteur ; John Vlachopoulos, Auteur Année de publication : 2007 Article en page(s) : p. 395-401 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : The rheological properties of two commercially available biodegradable polyesters - poly(lactic acid) (PLA) and aliphatic-aromatic co-polyester EcoflexTM - have been investigated. The rheological study was focused on measuring the viscosity and examining sharkskin, melt fracture, and extrudate swell phenomena, which are crucial in industrial applications. The experiments show that the two biodegradable polyesters exhibit shear-thinning behavior similar to other polymers and the Cox-Merz rule is obeyed. It was observed that with increasing shear rate PLA exhibits sharkskin and gross melt fracture while EcoflexTM exhibits only gross melt fracture. Experimental results indicate that both biodegradable polyesters exhibit small extrudate swell, up to 28% for PLA and up to 34% for EcoflexTM. DOI : 10.3139/217.2053 En ligne : https://drive.google.com/file/d/1m-jb34vPC9-m2PWWJETor-8mjT7HqNrO/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2680
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Titre : Biaxial orientation of polylactide/thermoplastic starch blends Type de document : texte imprimé Auteurs : N. Chapleau, Auteur ; M. A. Huneault, Auteur ; H. Li, Auteur Année de publication : 2007 Article en page(s) : p. 402-409 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : The biaxial stretchability and film properties of polylactide/thermoplastic starch blends were investigated. Polylactide (PLA) and thermoplastic starch (TPS) were blended in various proportions. Blends containing 27, 42 and 60 wt.% TPS were prepared via a twin-screw extrusion process. Interfacial modification was performed by grafting the PLA with maleic anhydride. These blends were subsequently cast into sheets and biaxially drawn using a laboratory biaxial stretcher. The morphology of extruded strands and cast sheets was investigated using scanning electron microscopy. The compatibilized blends exhibited a much finer morphology as well as preferential minor phase size orientation along the machine direction. The addition of starch did not affect significantly the biaxial stretchability of the pure PLA. Even at high starch content (60 wt.%), the biaxial draw ratio at which the sample breaks is very similar to that of the pure PLA. At higher temperatures, all blends could be stretched at significantly much higher biaxial draw ratio and very thin films could be obtained. The starch content and processing variables affected the tensile properties. DOI : 10.3139/217.2070 En ligne : https://drive.google.com/file/d/1OUfnIVMTvNoknd0UeGA5LrANHEKzeFS2/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2681
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Titre : Effects of starch types on mechanical properties of poly(lactic acid)/starch composites Type de document : texte imprimé Auteurs : X. S. Sun, Auteur ; W. Li, Auteur ; R. Acioli-Moura, Auteur Année de publication : 2007 Article en page(s) : p. 410-417 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Poly(lactic acid) (PLA) and its blends with starch and methylenediphenyl diisocyanate (MDI) were extruded in a twin-screw extruder and compress-molded in a dog-bone shaped tensile bars to form test specimens. The effects of starch types (rice, corn, wheat, and potato) on mechanical properties of the PLA/starch/MDI composites were evaluated. Starch type and granule size had no significant effects on mechanical properties of the composite. But crystallinity of the composite decreased as the starch granule size increased. Potato starch was used to study effects of granule size (19 to 63 µm) on mechanical properties of the PLA/starch composites. Both tensile strength and elongation of the PLA/starch/MDI (55/45/0.5) composites reduced slightly as starch granule size increased from 19 to 63 µm. While crystallinity of the composites was significantly decreased as granule size increased. Modulus of the composites remained the same regardless starch types and granule size. DOI : 10.3139/217.2052 En ligne : https://drive.google.com/file/d/1VpZ-gY4WLF4LgJoQX7gO4pw7GIEUa1Wp/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2682
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Titre : Solid and microcellular polylactide-carbon nanotube nanocomposites Type de document : texte imprimé Auteurs : S. Pilla, Auteur ; A. Kramschuster, Auteur ; S. Gong, Auteur ; A. Chandra, Auteur ; Lih-Sheng Turng, Auteur Année de publication : 2007 Article en page(s) : p. 428-428 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : In this study, polylactide (PLA)-multi-walled carbon nanotube (MWCNT) nanocomposites were melt-compounded using a twin-screw extruder. Solid and microcellular tensile bar specimens were produced via conventional and microcellular injection molding, respectively. Various characterization techniques were applied to study the static and dynamic mechanical properties, degree of MWCNT dispersion, cell morphology, and crystallization behavior. The addition of a small amount of MWCNTs led to a decrease in the cell size and an increase in the cell density of the microcellular PLA specimens. A transmission electron microscopy analysis of the PLA-MWCNT specimens revealed a higher degree of MWCNT dispersion in the microcellular PLA-MWCNT composite compared with its solid counterpart, indicating that the microcellular injection molding process further dispersed the MWCNTs. For both solid and microcellular specimens, the addition of 1.5 wt% MWCNTs reduced the specific strength, specific toughness and strain-at-break while exerting less impact on the specific modulus. The storage modulus was not affected significantly with the addition of MWCNTs, but was found to be higher for the microcellular specimens compared with their solid counterparts. Finally, the crystallinity of PLA increased with the addition of MWCNTs. DOI : 10.3139/217.2071 En ligne : https://drive.google.com/file/d/1n3G-UvKk_A8cvQnt6fkUh-5frZJOvCMF/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2683
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Titre : Tapioca starch-poly (lactic acid)-based nanocomposite foams as affected by type of nanoclay Type de document : texte imprimé Auteurs : S. Y. Lee, Auteur ; Y. X. Xu, Auteur ; M. A. Hanna, Auteur Année de publication : 2007 Article en page(s) : p. 429-435 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Tapioca starch (TS), poly (lactic acid) (PLA), and clay nanocomposite foams, with three clays (Cloisite 30B, Na+, and 20A), were prepared by melt-intercalation method. The structural, thermal, physical and mechanical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and Instron universal testing machine, respectively. XRD results indicated that the intercalation of TS/PLA into the nanoclay layers occurred for all three clays. The extents of intercalation depended on the types of clay and were exhibited in the sequence of Cloisite 30B > Na+ > 20A. At the same time, a mixture of intercalation and tactoid phenomena was observed for the TS/PLA/Cloisite Na+ nanocomposite. SEM results indicated a decrease in cell size of the TS/PLA foam matrix with the addition of nanoclay and cells had hexagonal and pentagonal shapes. Melting temperature (Tm) decreased with the addition of clays into TS/PLA matrix. Expansion ratios of the nanocomposites were significantly different (p < 0.05) from each other. TS/PLA/Cloisite Na+ nanocomposite had the highest expansion ratio of 20.9 compared to its TS/PLA/Cloisite 20A (9.65) and TS/PLA/Cloisite 30B counterparts (8.23). Addition of Cloisite Na+ resulted in the lowest unit density of 0.046 kg/m3, while no significant differences in unit density were observed for the foams with addition of Cloisite 30B and Cloisite 20A. Bulk spring index (BSI) was influenced significantly (p < 0.05) with the addition of nanoclays into the TS/PLA matrix. TS/PLA/Cloisite Na+ nanocomposite had the lowest BSI of 0.936. The bulk compressibility was decreased from 14.1 MPa for pure tapioca starch foam to 4.45 MPa with the addition of PLA. The nanocomposite with Cloisite 30B showed the highest value of 17.4 MPa, followed by those with Cloisite 20A (10.4 MPa), and Cloisite Na+ (6.47 MPa). DOI : 10.3139/217.2054 En ligne : https://drive.google.com/file/d/1ef5Zg8J-zpWQYLTdS3isuuPaw8wn8tLP/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2684
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Titre : Injection molded solid and microcellular polylactide compounded with recycled paper shopping bag fibers Type de document : texte imprimé Auteurs : A. Kramschuster, Auteur ; S. Pilla, Auteur ; S. Gong, Auteur ; A. Chandra, Auteur ; Lih-Sheng Turng, Auteur Année de publication : 2007 Article en page(s) : p. 436-445 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Recycled paper shopping bag fibers were melt-compounded using a batch mixer with biobased/biodegradable polylactide (PLA) at 10 and 30 wt.% using silane as a coupling agent. These PLA/fiber composites were then injection molded to produce both solid and microcellular tensile bars. The mechanical properties (specific modulus, specific tensile strength, specific toughness, and strain at break) of the neat PLA and PLA composites were tested and the cell morphology of the microcellular samples was examined using scanning electron microscopy. It was observed that the addition of the recycled paper shopping bag fibers resulted in an increase in cell density and decrease in average cell size for the microcellular components when compared with the neat PLA. The addition of the fibers increased the specific modulus of both solid and microcellular components, and high fiber contents (30 wt.%) resulted in an increase in specific tensile strength, yet yielded a decrease in the strain at break and specific toughness. The storage modulus was also improved with the addition of 10 and 30 wt.% fibers for both solid and microcellular components. DOI : 10.3139/217.2063 En ligne : https://drive.google.com/file/d/1SZj3Ywt82RoXbqqCzfNEw6FA2C-ft5Wm/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2685
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Titre : The linear viscoelastic behavior of a series of 3-hydroxybutyrate-based copolymers Type de document : texte imprimé Auteurs : D. H. Melik, Auteur ; G. M. Harrison, Auteur Année de publication : 2007 Article en page(s) : p. 455-462 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : The thermal and linear viscoelastic behavior of a series of synthetically produced 3-hydroxybutyrate-based copolymers is reported. The comonomers employed include 4-hydroxybutyrate (4HB), 5-hydroxyvalerate (5HV), and 6-hydroxyhexanoate (6HH). The polymers investigated differed in the concentration of comonomer randomly distributed within the material and in the length of the carbon backbone of the comonomer. The glass transition temperature follows the Fox equation and decreases with increasing comonomer concentration. The molecular weight between entanglements Me was determined from the linear viscoelastic data for each copolymer, and a mixing rule was used to determine Me for homopolymers made from the comonomers studied. Depending on comonomer type and concentration, Me can be varied systematically, resulting in a wide range of potential applications depending on the chemistry employed. Using the complex viscosity data, master curves were constructed for both the zero-shear viscosity and the shear-thinning behavior depending upon the temperature and the molecular weight between entanglements. The analysis of rheological results and polymer properties based upon copolymer content provides an opportunity to process bio-based materials for a wide range of applications. DOI : 10.3139/217.2062 En ligne : https://drive.google.com/file/d/1cObR54nvCYt2EtX4jFhTVA0KyjIfRLtM/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2686
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Titre : New developments in biodegradable starch-based nanocomposites Type de document : texte imprimé Auteurs : Jean-Marie Raquez, Auteur ; Y. Nabar, Auteur ; R. Narayan, Auteur ; P. Dubois, Auteur Année de publication : 2007 Article en page(s) : p. 463-470 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : This contribution outlines the new developments in thermoplastic starch-based (nano)composites useful for more specific applications compatible with our environment, partially based on our ongoing research over the past few years. Accordingly, melt-intercalating starch macromomolecules into layered silicates (e.g., natural clays) has proved to be an efficient way for preparation of thermoplastic starch-layered silicate nanocomposites with interesting thermo-mechanical properties, as well as improved solvent-resistance. Cellulosic (nano)whiskers were also added as another environmentally benign (nano)filler in starch-based compositions. The design of such thermoplastic starch-based (nano)composites with enhanced properties relies upon the control over the phase behavior and morphology of the nanofiller within the matrix by more defined interfacial compatibility as well as by fine tuning of processing parameters. A special emphasis was also given to the introduction of layered silicates (nano)filler in biodegradable melt-blends made of hydrophilic thermoplastic starch and hydrophobic biodegradable polyesters as a valuable way to increase the compatibility between the two polymeric partners. DOI : 10.3139/217.2076 En ligne : https://drive.google.com/file/d/1Nc5iEUUKaJjari7_qZIQ7PJ3x9tWhdjE/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2687
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Titre : Viscous properties of thermoplastic starches from different botanical origin Type de document : texte imprimé Auteurs : G. Della Valle, Auteur ; Bruno Vergnes, Auteur ; D. Lourdin, Auteur Année de publication : 2007 Article en page(s) : p. 471-479 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Starches from various botanical origins were plasticized in a twin screw extruder with different glycerol contents (from 23 to 32%, total wet basis) in order to prepare pellets of amorphous thermoplastic starches (TPS) that can further be processed for manufacturing purposes. The viscous behaviour of these starches was studied with a capillary pre-shearing rheometer, which achieved an homogeneous molten phase under controlled thermomechanical conditions. After performing Bagley corrections and Rabinowitsch analysis, it was found that all samples exhibited a non-Newtonian shear-thinning behaviour, which could be modeled in the range 1 to 103 s-1 either by a simple power law or by a Herschel-Bulkley relationship. For the consistency index, the influence of temperature and plasticizer content was accounted for by Arrhenius-like laws, applying time-temperature and time-plasticizer superposition. For the same plasticizer content and temperature, comparison of starches from different botanical origins showed that shear viscosity values usually increased with the starch amylose content. This trend was partly confirmed for the elongational behaviour, estimated by the Cogswell's analysis of entrance effects. These results can be interpreted by the greater ability of linear molecules of amylose to entangle, compared to the more compact amylopectin molecules. DOI : 10.3139/217.2057 En ligne : https://drive.google.com/file/d/1ear6mYyYr609DZ1ijjQhfE2cU4OVxvzY/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2688
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Titre : Thermoplastic foams from zein and gelatin Type de document : texte imprimé Auteurs : A. Salerno, Auteur ; M. Oliviero, Auteur ; E. Di Maio, Auteur ; S. Iannace, Auteur Année de publication : 2007 Article en page(s) : p. 480-488 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Biopolymères
GélatineLa gélatine est une substance solide translucide, transparente ou légèrement jaune, presque sans goût et sans odeur, obtenue par l'ébullition prolongée de tissus conjonctifs (peaux) ou d'os d'animaux (principalement porc, bœuf, poisson). Elle possède de nombreuses applications dans le domaine culinaire, la médecine, les industries agroalimentaire et pharmaceutique.
En matière d’étiquetage, la gélatine est considérée par la norme européenne3 comme un ingrédient et non pas comme un additif, c'est pourquoi elle n'a pas de numéro E. Hors Union européenne, elle est considérée par certains pays comme un additif gélifiant et on peut la trouver avec la dénomination E441.
La gélatine est un mélange de protéines obtenu par hydrolyse partielle du collagène extrait de la peau comme la peau de porc (cochon), des os, des cartilages, etc. Les liaisons moléculaires entre les fibres de collagène sont alors brisées. Mélangée à de l'eau, la gélatine forme un gel colloïdal semi-solide thermo-réversible (il fond lorsqu'il est chauffé et recouvre son aspect gélatineux lorsqu'il est refroidi). Sous forme déshydratée, par contre, la gélatine n'a pas de point de fusion et devient friable ou brûle quand elle est chauffée à trop haute températureLa rhéologie de la gélatine se caractérise par un comportement viscoélastique, et des contraintes trop élevées ou appliquées trop rapidement peuvent entraîner une rupture fragile (fracturation) ou ductile6. Le caractère plutôt élastique/fragile ou plutôt visqueux/ductile dépend de la concentration en gélatine de la solution aqueuse et de la température, ainsi que de la durée de la mise sous contrainteLes acides aminés constituant la gélatine sont : la glycine (21 %), la proline (12 %), l'hydroxyproline (12 %), l'acide glutamique (10 %), l'alanine (9 %), l'arginine (8 %), l'acide aspartique (6 %), la lysine (4 %), la sérine (4 %), la leucine (3 %), la valine, la phénylalanine et la thréonine (2 %), l'isoleucine et l'hydroxylysine (1 %), la méthionine et l'histidine (< 1 %) et la tyrosine (< 0,5 %). Ces valeurs sont variables (surtout pour les constituants minoritaires) et dépendent de la source de matériaux bruts et de la technique de préparation. La gélatine est constituée à environ 98-99 % (en poids sec) de protéines et contient 18 acides aminés dont huit des neuf acides aminés essentiels à l'Homme. Elle n'a qu'une relative valeur nutritionnelle du fait de l'absence de tryptophane et de son déficit en isoleucine, thréonine et méthionine; elle possède également un taux inhabituellement élevé d'acides aminés non essentiels, la glycine et la proline (qui sont produits par le corps humain). (Wikipedia)
Mousses plastiques
ThermoplastiquesUne matière thermoplastique désigne une matière qui se ramollit (parfois on observe une fusion franche) d'une façon répétée lorsqu'elle est chauffée au-dessus d'une certaine température, mais qui, au-dessous, redevient dure. Une telle matière conservera donc toujours de manière réversible sa thermoplasticité initiale. Cette qualité rend le matériau thermoplastique potentiellement recyclable (après broyage). Cela implique que la matière ramollie ne soit pas thermiquement dégradée et que les contraintes mécaniques de cisaillement introduites par un procédé de mise en forme ne modifient pas la structure moléculaire.
ZéineLa zéine est une classe de protéine prolamine du grain de maïs. Elle est en général produite sous forme de poudre à partir du gluten de maïs.
La zéine est utilisée dans un grand nombre d'applications industrielles et alimentaires. Historiquement, elle a été employée pour la fabrication d'une vaste gamme de produits commerciaux, dont des revêtements pour gobelets en carton ou bouchons de bouteilles de sodas, des étoffes d'habillement, des boutons, des adhésifs, des enduits et des liants. La zéine pure est incolore, inodore, sans saveur, dure, insoluble dans l'eau et comestible, ce qui la rend inestimable pour les produits alimentaires et pharmaceutiques, en concurrence avec la gomme laque. Elle est actuellement utilisée comme enrobage pour bonbons, cacahuètes, fruits, pilules et autres aliments ou médicaments encapsulés.
La zéine peut être transformée en résines et autres polymères bioplastiques qui peuvent être extrudés ou roulés en divers produits plastiques. En raison des préoccupations environnementales croissantes à propos des revêtements synthétiques et l'augmentation actuelle du prix des produits pétrochimiques, l'attention se concentre sur la zéine comme matière première de nombreuses applications de polymères non toxiques et renouvelables, en particulier dans l'industrie du papier. La zéine présente beaucoup d’intérêt concernant les coûts d'élimination des matières plastiques et celui aussi du consommateur pour les substances naturelles. Les applications potentielles dans l'agro-alimentaire sont nombreuses.Index. décimale : 668.9 Polymères Résumé : The aim of this study was to characterize the foaming of natural proteins as thermoplastic polymers. In particular, two proteins, one of vegetal origin, zein, and one of animal origin, gelatin, were processed to achieve thermoplastic polymers, and subsequently foamed by a gas foaming batch process. The effects of suitable plasticizing additives and melt-mixing process on the thermal and mechanical properties of the thermoplasticized proteins were evaluated to assess the thermoplastic characteristics of these materials. Furthermore, selected protein/plasticizers systems were foamed with mixtures of CO2 and N2 as blowing agents, in a batch foaming apparatus, at different temperatures, pressures and pressure drop rates, to evaluate the processing window and the final properties of the foams. Foams with densities of 0.1 g/cm3 and morphologies characterized by uniform distributions of cells with 10 µm diameters were obtained. Results indicated the suitability of zein and gelatin for being processed with classical thermoplastic processing technologies including melt mixing and foaming and their potentials as biodegradable polymers. DOI : 10.3139/217.2065 En ligne : https://drive.google.com/file/d/1yXFH-BFsvZFz2TSYSkNd_0rPbwAFxPYx/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2689
in INTERNATIONAL POLYMER PROCESSING > Vol. XXII, N° 5 (11/2007) . - p. 480-488[article]Réservation
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Titre : Improvement of the mechanical properties of soy protein isolate based plastics through formulation and processing Type de document : texte imprimé Auteurs : M. Baboi, Auteur ; G. Srinivasan, Auteur ; J.-L. Jane, Auteur ; D. Grewell, Auteur Année de publication : 2007 Article en page(s) : p. 489-496 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : This paper reviews the characterization of the base strength and impact of water absorption on biodegradable, namely, soy protein-based plastics prepared by different methods. The initial approach included using different quantities of soy hydrolysate plasticized with glycerol, which is widely known for its plasticizing effect. With the second approach, the raw polymer was which plasticized with glycerol compounded with different additives such as polycaprolactone or zinc sterate, and was also heat-treated at various temperatures after injection molding. The results indicated the polycaprolactone and, respectively, a medium to high heat treatment significantly enhanced tensile strength and greatly decreased water absorption. The soy hydrolysate formulations that were studied enhanced tensile strength but didn not significantly improve elongation or water absorption. DOI : 10.3139/217.2074 En ligne : https://drive.google.com/file/d/1If47IM-BoSzBFvU2fchlYXNQJ41pTkQa/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2690
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Titre : Biocomposites based on bacterial cellulose and apple and radish pulp Type de document : texte imprimé Auteurs : S. Gea, Auteur ; F. G. Torres, Auteur ; O. P. Troncoso, Auteur ; C. T. Reynolds, Auteur ; F. Vilasecca, Auteur ; M. Iguchi, Auteur ; T. Peijs, Auteur Année de publication : 2007 Article en page(s) : p. 497-501 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Bacterial cellulose (BC) pellicles obtained from an Acetobacter xylinum culture were disintegrated using mechanical methods to be used as reinforcement to produce biocomposite sheets with Apple and Radish Pulp. The nanosize disintegrated BC pellicles were blended with microsize apple and radish pulp in the wet state and then hot pressed to produce paper-like sheets. Thermal analysis was carried out by Thermogravimetry Analysis (TGA). Mechanical properties were assessed by Quasistatic Tensile Tests and Dynamic Mechanical Analysis (DMA). High tensile moduli were obtained (up to 8 GPa) and a nearly linear dependence of Young's modulus on the BC volume fraction was observed. Morphological characterisation of biocomposite sheets and fracture surfaces performed by Scanning Electron Microscopy (SEM) revealed the structure of the disintegrated cellulose network and the failure mechanisms of the biocomposites. DOI : 10.3139/217.2059 En ligne : https://drive.google.com/file/d/1k2RpIhrbdBmiW3Hum0ENLhiGvzMbJwoV/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2691
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Titre : Preparation and properties of metallocene-catalyzed PE/starch nanocomposites : role of nanocompatibilizer Type de document : texte imprimé Auteurs : S.-M. Lai, Auteur ; K.-T. Ti, Auteur Année de publication : 2007 Article en page(s) : p. 502-511 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : The properties of metallocene catalyzed polyethylene (mPE)/starch blends and nanocomposites containing mPE-g-maleic anhydride (mPE-g-MA) compatibilizer, reinforced with 1 phr commercial organoclay (20A) at various amounts of pristine starch are discussed. The results from X-ray diffraction (XRD) and transmission electron microscope (TEM) experiments revealed that nanocomposites were achieved in all cases. No observable diffraction peaks in the low angle region were detected. Clay was preferentially located within the mPE and starch interface and the mPE matrix. The crystallization temperatures of nanocomposites increased with the addition of clay acting as a nucleating agent. However, the melting temperatures and the glass transition temperatures remained largely unchanged. Clay incorporation provided a heat barrier that profoundly increased the blend thermal stability. A maximum increase in tensile strength and Young's modulus was obtained, up to 60% and 105%, respectively, using nanoclay reinforced compatibilizer (termed nanocompatibilizer) in comparison with neat compatibilizer for pristine starch filled cases. Slightly lower water absorption capability was observed for nanocompatibilizer reinforced cases through the sheet-like structure of clay compared with neat compatibilizer cases. DOI : 10.3139/217.2051 En ligne : https://drive.google.com/file/d/1nDCsBKHa-0ydYI_a6ZkFz9FWx9xXybbK/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2692
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Titre : Evaluation of properties and biodeterioration potential of polyethylene and aliphatic polyester blends Type de document : texte imprimé Auteurs : A. V. Machado, Auteur ; I. Moura, Auteur ; Fernando M. Duarte, Auteur ; G. Botelho, Auteur ; R. Nogueira, Auteur ; A. G. Brito, Auteur Année de publication : 2007 Article en page(s) : p. 512-518 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Blends of high density polyethylene (HDPE) and biodegradable polymers - polylactic acid, PLA, poly(e-caprolactone), PCL and Mater-Bi|Superscript|®|/Superscript| (thermoplastic starch (TPS) with PLA or PCL) - were prepared in a co-rotating twin-screw extruder, together with polyethylene modified with maleic anhydride (PE-g-MA) used as compatibiliser. The mechanical and rheological properties, morphology and potential for biodeterioration of polymeric materials were evaluated. Blends with PLA showed a reduced elongation at break but an increased Young's modulus while the addition of PCL led to materials with a greater elongation at break and a lower Young modulus. The rheological results evidenced that HPDE and the blend with the highest TPS level exhibited the highest viscosity. The microbial growth test carried out to evaluate the potential for biodeterioration of the blends, using a pure culture of Pseudomonas fluorescens, indicated that HDPE/PCL had a lower resistance to bacterial attack than the blend of HDPE/PLA. This was verified by a higher cell number on its surface after 10 weeks of incubation. The addition of 30 % starch to the HDPE/PLA blend enhanced its biodeterioration potential, the same was not observed in the case of the HDPE/PCL blend containing just 18 % starch. DOI : 10.3139/217.2061 En ligne : https://drive.google.com/file/d/1myfOtTmtR596MF4nE8fO30WaD6g4zw73/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2693
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Titre : Fabrication of porous 3-D structure from poly(L-lactide)-based nanocomposite foam via enzymatic degradation Type de document : texte imprimé Auteurs : M. Bitou, Auteur ; M. Okamoto, Auteur Année de publication : 2007 Article en page(s) : p. 446-454 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : In order to prepare a porous three-dimensional (3-D) structure in biodegradable polyester materials we have conducted the enzymatic degradation of a poly(L-lactide) (PLLA)-based nano-composite foam, having a nanocellular structure, using proteinase-K as a degrading agent at 37°C. The surface and cross sectional morphologies of the foam recovered after enzymatic hydrolysis for different intervals were investigated by using a scanning electron microscope. The nanocellular material took up a large amount of water, which led to the swelling of the foam due to the large surface area inside the nanocelluar structure, and facilitated the enzymatic degradation of the PLLA matrix as compared with the bulk (pre-foamed) sample. Consequently, we have successfully prepared a porous 3-D structure as a remaining scaffold in the core part of the nano-composite foam, reflecting the spherulites of the crystallized PLLA. DOI : 10.3139/217.2073 En ligne : https://drive.google.com/file/d/1UTlOjc414hKXdKuOxLfIa7sYmMhpf65P/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2694
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| Code-barres | Cote | Support | Localisation | Section | Disponibilité |
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| 008361 | - | Périodique | Bibliothèque principale | Documentaires | Disponible |
