The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
E Baer - One of the best experts on this subject based on the ideXlab platform.
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gradient multilayer films by forced assembly Coextrusion
Industrial & Engineering Chemistry Research, 2010Co-Authors: Michael Ponting, Anne Hiltner, James H Andrews, Tiffani M Burt, Lashanda T J Korley, E BaerAbstract:Forced assembly polymer Coextrusion utilizes layer multiplication to produce films with tens or thousands of micrometer to nanometer thick layers. The development of novel uneven split layer multiplying dies has produced gradient multilayer films with at least a 10 times difference between the thickest and thinnest layers. Coextrusion through a series of equal and uneven split multiplier dies allows for flexibility in the unique design of layer thickness distributions by: (1) altering the multiplier offset and (2) changing the sequence of a series of uneven split multiplying dies with different splitting ratios. This new technology has created highly reflective, multilayered photonic films with gradient layer thickness distributions exhibiting, as examples, a 600 nm wide reflection band and dual optical reflection bands within a single film. Also, gradient multilayers exhibit unique mechanical behavior. A layer thickness dependent craze to shear banding deformation mechanism was observed. In addition, gra...
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layered polymeric optical systems using continuous Coextrusion
Proceedings of SPIE, 2009Co-Authors: Hyunmin Song, Anne Hiltner, Kenneth D Singer, Yeheng Wu, Juefei Zhou, Joe Lott, James H Andrews, E Baer, Christoph WederAbstract:Polymers are receiving considerable attention as components in novel optical systems because of the tailored functionality, ease of manufacturing, and relatively low cost. The processing of layered polymeric systems by Coextrusion is a method to produce films comprising hundreds to thousands of alternating layers in a single, one-step roll-to-roll process. Several layered polymer optical systems have been fabricated by Coextrusion, including gradient refractive index lenses, tunable refractive index elastomers, photonic crystals, and mechanically tunable photonic crystals. Layered polymeric optical systems made by Coextrusion can also incorporate active components such as photoreactive additives for multilayered patterning and laser dyes for all-polymer laser systems. Coextrusion is a process which allows for the flexible design of polymeric optical systems using layers with thickness spanning the nanoscale to the microscale.
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microlayer Coextrusion as a route to innovative blend structures
Polymer Engineering and Science, 2001Co-Authors: D Jarus, Anne Hiltner, E BaerAbstract:Nanolayer and microlayer Coextrusion is a method for combining two or three polymers as hundreds or thousands of alternating layers with individual layers as thin as tens of nanometers. The possibility for utilizing microlayer Coextrusion as a tool for creating microplatelets of high aspect ration was explored. Polypropylene (PP) was combined with polyamide-66 (PA66) in microlayers. A high volume fraction of PA66 microplatelets dispersed in PP was achieved by injection molding the microlayered materials at a temperature intermediate between the melting points of the two constituents. The difference in melting temperatures provided a broad processing window of about 60°C in which the PP layers melted to form the matrix whereas the PA66 layers remained in the solid state as dispersed microplatelets of high aspect ration. The resulting material had significantly improved oxygen barrier properties. An enhancement of 4–5 times over the barrier of the conventional melt blend resulted from increased tortuosity of the diffusion pathway.
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novel structures by microlayer Coextrusion talc filled pp pc san and hdpe lldpe
Polymer Engineering and Science, 1997Co-Authors: C Mueller, Anne Hiltner, Sergei Nazarenko, T Ebeling, Thomas L Schuman, E BaerAbstract:Numerous examples in the literature illustrate how the Coextrusion of film with three or more polymeric layers is economically used to achieve a desirable mix of end-use characteristics. More recently, layer-multiplying devices permit two polymers of widely dissimilar solid-state properties to be combined into unique microlayer and nanolayer structures with hundreds or thousands of alternating layers. If the layers are thin enough, the key properties of the constituents can combine synergistically. The microlayer structure is also an effective research tool. Because the microlayer and nanolayer structures contain large specific interfacial areas, they are ideal for fundamental studies of phenomena such as interdiffusion and adhesion. Three examples of microlayered materials with up to 1024 layers illustrate the versatility of this Coextrusion process: talc-filled PP. PC/SAN, and HDPE/ LLDPE.
Cyrille Sollogoub - One of the best experts on this subject based on the ideXlab platform.
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existence of a critical layer thickness in ps pmma nanolayered films
Macromolecules, 2017Co-Authors: Adrien Bironeau, Guillaume Miquelardgarnier, Thomas Salez, Cyrille SollogoubAbstract:An experimental study was carried out to investigate the existence of a critical layer thickness in nanolayer Coextrusion, under which no continuous layer is observed. Polymer films containing thousands of layers of alternating polymers with individual layer thicknesses below 100 nm have been prepared by Coextrusion through a series of layer multiplying elements. Different films composed of alternating layers of poly(methyl methacrylate) (PMMA) and polystyrene (PS) were fabricated with the aim to reach individual layer thicknesses as small as possible, varying the number of layers, the mass composition of both components, and the final total thickness of the film. Films were characterized by atomic force microscopy (AFM), and a statistical analysis was used to determine the distribution in layer thicknesses and the continuity of layers. For the PS/PMMA nanolayered systems, results point out the existence of a critical layer thickness around 10 nm, below which the layers break up. This critical layer thick...
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dispersion of carbon nanotubes in polypropylene via multilayer Coextrusion influence on the mechanical properties
Polymer, 2013Co-Authors: Guillaume Miquelardgarnier, Cyrille Sollogoub, Alain Guinault, Didier Fromonteil, Stephane DelalandeAbstract:Multilayer Coextrusion was used to disperse Carbon Nanotubes (CNT) in polypropylene (PP). The dilution of commercially available masterbatches using a twin-screw extruder was first applied to produce several formulations, which were then mixed with PP using a multilayer Coextrusion device to obtain films or pellets with CNT concentrations between 0.1 and 1%wt. The influence of the specific mechanical energy (SME) during the dilution step, of the addition of a compatibilizer, and of the multilayer tool on the CNT dispersion within the matrix was highlighted. The effect of the dispersion on the thermomechanical properties of the resulting materials was studied. We showed notably that films containing 0.2%wt CNT, 1%wt of PPgAm, prepared at high SME presented a Young's modulus increase of 25e30% without significant decrease in the elongation at break. These results, using low amounts of CNT and industrially available devices, may show a new path for producing nanocomposites.
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Microlayer Coextrusion process as a way to improve thermomechanical properties of ABS/PC blends
2011Co-Authors: Cyrille Sollogoub, Anne Grandmontagne, Alain GuinaultAbstract:ABS/PC blends have always presented a great interest both in industrial and academic contexts, since they combine the most desirable properties of both ABS and PC. Melt blends are classically prepared using a twin screw extruder. In this study, ABS/PC blends of two compositions were prepared with two blending techniques: Coextrusion mixing method (CM) and microlayer Coextrusion method (MC), designed to better control the blend morphology, and then injection molded. SEM observations show that different blend morphologies have been obtained, depending on the blending technique. It was shown that microlayer Coextrusion process can lead to orientated morphology phase (fibrillar and lamellar structures), whereas Coextrusion mixing method leads only to nodular morphology. These morphologies have been correlated with thermomechanical properties (tensile tests and DMTA). Improved mechanical performances are achieved with the microlayer Coextrusion process.
Anne Hiltner - One of the best experts on this subject based on the ideXlab platform.
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gradient multilayer films by forced assembly Coextrusion
Industrial & Engineering Chemistry Research, 2010Co-Authors: Michael Ponting, Anne Hiltner, James H Andrews, Tiffani M Burt, Lashanda T J Korley, E BaerAbstract:Forced assembly polymer Coextrusion utilizes layer multiplication to produce films with tens or thousands of micrometer to nanometer thick layers. The development of novel uneven split layer multiplying dies has produced gradient multilayer films with at least a 10 times difference between the thickest and thinnest layers. Coextrusion through a series of equal and uneven split multiplier dies allows for flexibility in the unique design of layer thickness distributions by: (1) altering the multiplier offset and (2) changing the sequence of a series of uneven split multiplying dies with different splitting ratios. This new technology has created highly reflective, multilayered photonic films with gradient layer thickness distributions exhibiting, as examples, a 600 nm wide reflection band and dual optical reflection bands within a single film. Also, gradient multilayers exhibit unique mechanical behavior. A layer thickness dependent craze to shear banding deformation mechanism was observed. In addition, gra...
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Polymer nanostructures by forced assembly: Process, structure, and properties
Macromolecular Symposia, 2010Co-Authors: Michael Ponting, Anne Hiltner, Eric BaerAbstract:The process of micro- and nanolayer Coextrusion of polymeric systems with good layer uniformity is described. Coextrusion through a series of layer multiplying die elements has enabled the production of films containing tens to thousands of layers with individual layer thicknesses from the micro- to the nanoscale. Improvements in layer uniformity are discussed through optimization of layer multiplier die design, selection of viscosity matched polymer systems, and incorporation of surface layer capabilities. Design of ‘uneven’ split layer multiplication dies has enabled the Coextrusion of layered films with a wide variety of layer thickness distributions having up to a 10 difference in the individual film layer thicknesses. Coextrusion of layered polymer films with individual layer thicknesses down to the nanoscale has resulted in the production of novel systems with improved properties. Nanolayered polymer films were utilized to develop an all-plastic polymer laser, to fabricate gradient refractive index lenses, and to investigate gas barrier enhancement of crystalline polymer nanolayers confined to induce a high aspect ratio, in-plane, single-crystal-like lamellar structure.
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layered polymeric optical systems using continuous Coextrusion
Proceedings of SPIE, 2009Co-Authors: Hyunmin Song, Anne Hiltner, Kenneth D Singer, Yeheng Wu, Juefei Zhou, Joe Lott, James H Andrews, E Baer, Christoph WederAbstract:Polymers are receiving considerable attention as components in novel optical systems because of the tailored functionality, ease of manufacturing, and relatively low cost. The processing of layered polymeric systems by Coextrusion is a method to produce films comprising hundreds to thousands of alternating layers in a single, one-step roll-to-roll process. Several layered polymer optical systems have been fabricated by Coextrusion, including gradient refractive index lenses, tunable refractive index elastomers, photonic crystals, and mechanically tunable photonic crystals. Layered polymeric optical systems made by Coextrusion can also incorporate active components such as photoreactive additives for multilayered patterning and laser dyes for all-polymer laser systems. Coextrusion is a process which allows for the flexible design of polymeric optical systems using layers with thickness spanning the nanoscale to the microscale.
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microlayer Coextrusion as a route to innovative blend structures
Polymer Engineering and Science, 2001Co-Authors: D Jarus, Anne Hiltner, E BaerAbstract:Nanolayer and microlayer Coextrusion is a method for combining two or three polymers as hundreds or thousands of alternating layers with individual layers as thin as tens of nanometers. The possibility for utilizing microlayer Coextrusion as a tool for creating microplatelets of high aspect ration was explored. Polypropylene (PP) was combined with polyamide-66 (PA66) in microlayers. A high volume fraction of PA66 microplatelets dispersed in PP was achieved by injection molding the microlayered materials at a temperature intermediate between the melting points of the two constituents. The difference in melting temperatures provided a broad processing window of about 60°C in which the PP layers melted to form the matrix whereas the PA66 layers remained in the solid state as dispersed microplatelets of high aspect ration. The resulting material had significantly improved oxygen barrier properties. An enhancement of 4–5 times over the barrier of the conventional melt blend resulted from increased tortuosity of the diffusion pathway.
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novel structures by microlayer Coextrusion talc filled pp pc san and hdpe lldpe
Polymer Engineering and Science, 1997Co-Authors: C Mueller, Anne Hiltner, Sergei Nazarenko, T Ebeling, Thomas L Schuman, E BaerAbstract:Numerous examples in the literature illustrate how the Coextrusion of film with three or more polymeric layers is economically used to achieve a desirable mix of end-use characteristics. More recently, layer-multiplying devices permit two polymers of widely dissimilar solid-state properties to be combined into unique microlayer and nanolayer structures with hundreds or thousands of alternating layers. If the layers are thin enough, the key properties of the constituents can combine synergistically. The microlayer structure is also an effective research tool. Because the microlayer and nanolayer structures contain large specific interfacial areas, they are ideal for fundamental studies of phenomena such as interdiffusion and adhesion. Three examples of microlayered materials with up to 1024 layers illustrate the versatility of this Coextrusion process: talc-filled PP. PC/SAN, and HDPE/ LLDPE.
Daisuke Sawai - One of the best experts on this subject based on the ideXlab platform.
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Superdrawing of polytetrafluoroethylene nascent powder by solid‐state Coextrusion
Journal of Polymer Science Part B, 2006Co-Authors: Daisuke Sawai, Daisuke Watanabe, Naoyuki Morooka, Haruka Kuroki, Tetsuo KanamotoAbstract:A film of nascent powder of polytetrafluoroethylene (PTFE), compacted below the ambient melting temperature (T m , 335 °C), was drawn by two-stage draw techniques consisting of a first-stage solid-state Coextrusion followed by a second-stage solid-state Coextrusion or tensile draw. Although the ductility of extrudates was lost for the second-stage tensile draw at temperatures above 150 °C due to the rapid decrease in strength, as previously reported, the ductility of extrudates increased with temperature even above 150 °C when the second-stage draw was made by solid-state Coextrusion, reflecting the different deformation flow fields in a free space for the former and in an extrusion die for the latter. Thus, a powder film initially coextruded to a low extrusion draw ratio (EDR) of 6-20 at 325 "C was further drawn by Coextrusion to EDRs up to ∼400 at 325-340 C, near the T m . Extremely high chain orientation (f c = 0.998 ± 0.001), crystallinity (96.5 ± 0.5)%, and tensile modulus (115 ± 5 GPa at 24 °C, corresponding to 73% of the X-ray crystal modulus) were achieved at high EDRs. Despite such a morphological perfection and a high modulus, the tensile strength of a superdrawn tape, 0.48 ± 0.03 GPa, was significantly low when compared with those (1.4-2.3 GPa) previously reported by tensile drawing above the T m . Such a low strength of a superdrawn, high-modulus PTFE tape was ascribed to the low intermolecular interaction of PTFE and the lack of intercrystalline links along the fiber axis, reflecting the initial chain-extended morphology of the nascent powder combined with the fairly high chain mobility associated with the crystal/crystal transitions at around room temperature.
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preparation of oriented β form poly l lactic acid by solid state Coextrusion effect of extrusion variables
Macromolecules, 2003Co-Authors: Daisuke Sawai, Kazuyo Takahashi, And Aki Sasashige, Tetsuo Kanamoto, Suonghyu HyonAbstract:A film of melt-crystallized poly(l-lactic acid) (PLLA) consisting of α-form crystals was uniaxially drawn by solid-state Coextrusion at 110−170 °C using split billets of different polymers. The effects of extrusion variables, including the extrusion draw ratio (EDR), temperature (Text), and pressure (Pext), on the crystal transformation from the initial α-form to the oriented β-form crystals were studied. The crystal transformation proceeded rapidly with EDR. It was found that when Coextrusion was made at a constant Pext and EDR but at different Text's, there was a Text (130 °C) where the crystal transformation proceeded most efficiently. Furtheremore, when Coextrusion was made at a constant Text and EDR but at different Pext's, the transformation proceeded more efficiently at a higher Pext. These results show that crystal transformation proceeds with the EDR most efficiently for the Coextrusion at a Text of 130 °C and a higher Pext. As a result of the specific effect for each of the extrusion variables o...
Tetsuo Kanamoto - One of the best experts on this subject based on the ideXlab platform.
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Superdrawing of polytetrafluoroethylene nascent powder by solid‐state Coextrusion
Journal of Polymer Science Part B, 2006Co-Authors: Daisuke Sawai, Daisuke Watanabe, Naoyuki Morooka, Haruka Kuroki, Tetsuo KanamotoAbstract:A film of nascent powder of polytetrafluoroethylene (PTFE), compacted below the ambient melting temperature (T m , 335 °C), was drawn by two-stage draw techniques consisting of a first-stage solid-state Coextrusion followed by a second-stage solid-state Coextrusion or tensile draw. Although the ductility of extrudates was lost for the second-stage tensile draw at temperatures above 150 °C due to the rapid decrease in strength, as previously reported, the ductility of extrudates increased with temperature even above 150 °C when the second-stage draw was made by solid-state Coextrusion, reflecting the different deformation flow fields in a free space for the former and in an extrusion die for the latter. Thus, a powder film initially coextruded to a low extrusion draw ratio (EDR) of 6-20 at 325 "C was further drawn by Coextrusion to EDRs up to ∼400 at 325-340 C, near the T m . Extremely high chain orientation (f c = 0.998 ± 0.001), crystallinity (96.5 ± 0.5)%, and tensile modulus (115 ± 5 GPa at 24 °C, corresponding to 73% of the X-ray crystal modulus) were achieved at high EDRs. Despite such a morphological perfection and a high modulus, the tensile strength of a superdrawn tape, 0.48 ± 0.03 GPa, was significantly low when compared with those (1.4-2.3 GPa) previously reported by tensile drawing above the T m . Such a low strength of a superdrawn, high-modulus PTFE tape was ascribed to the low intermolecular interaction of PTFE and the lack of intercrystalline links along the fiber axis, reflecting the initial chain-extended morphology of the nascent powder combined with the fairly high chain mobility associated with the crystal/crystal transitions at around room temperature.
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preparation of oriented β form poly l lactic acid by solid state Coextrusion effect of extrusion variables
Macromolecules, 2003Co-Authors: Daisuke Sawai, Kazuyo Takahashi, And Aki Sasashige, Tetsuo Kanamoto, Suonghyu HyonAbstract:A film of melt-crystallized poly(l-lactic acid) (PLLA) consisting of α-form crystals was uniaxially drawn by solid-state Coextrusion at 110−170 °C using split billets of different polymers. The effects of extrusion variables, including the extrusion draw ratio (EDR), temperature (Text), and pressure (Pext), on the crystal transformation from the initial α-form to the oriented β-form crystals were studied. The crystal transformation proceeded rapidly with EDR. It was found that when Coextrusion was made at a constant Pext and EDR but at different Text's, there was a Text (130 °C) where the crystal transformation proceeded most efficiently. Furtheremore, when Coextrusion was made at a constant Text and EDR but at different Pext's, the transformation proceeded more efficiently at a higher Pext. These results show that crystal transformation proceeds with the EDR most efficiently for the Coextrusion at a Text of 130 °C and a higher Pext. As a result of the specific effect for each of the extrusion variables o...