The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Philippe Dubois - One of the best experts on this subject based on the ideXlab platform.
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modification of poly ethylene 2 5 furandicarboxylate with biobased 1 5 pentanediol significantly toughened copolyesters retaining high tensile strength and o2 Barrier property
Biomacromolecules, 2019Co-Authors: Hongzhou Xie, Philippe DuboisAbstract:Poly(ethylene 2,5-furandicarboxylate) (PEF) is a biobased polyester characterized by high gas Barrier properties as well as high tensile modulus and strength, but poor toughness. Toughening PEF without sacrificing its modulus, strength and gas Barrier Performance is a great challenge for PEF modification. In this study, high molecular weight random poly(ethylene- co-1,5-pentylene 2,5-furandicarboxylate)s (PEPeFs) were synthesized via melt copolycondensation of 2,5-furandicarboxylic acid (FDCA), ethylene glycol (EG) and 1,5-pentanediol (PeDO), a cheap, biobased and commercially available odd-carbon comonomer. The synthesized PEPeFs were characterized and assessed with intrinsic viscosity, ATR-FTIR, 1H NMR, DSC, TGA and tensile, impact and O2 permeation test. Mayo-Lewis equation with "reactivity ratio" of 3.78 for PeDO and 0.75 for EG could be used as an empirical equation to correlate the copolyester composition (ϕPeF) with monomer composition. PEPeFs proved nearly amorphous copolyesters having excellent thermal stability. Brittle-ductile transition was achieved at ϕPeF as low as 9 mol %. Increasing ϕPeF led to increase in elongation at break and notch impact strength and decrease in Tg, O2 Barrier Performance and tensile modulus and strength. However, in comparison with PEF, PEF-rich PEPeFs (ϕPeF 9-47%) not only showed greatly improved elongation at break (29-265% vs 4%) and enhanced impact strength (2.2-3.9 kJ/m2) but also retained very high Young's modulus (2.8-3.3 vs 3.3 GPa) and yielding strength (72-83 vs 82 MPa). Particularly, when compared with bottle-grade PET, PE82Pe18F possesses equal Tg (ca. 75 °C) and comparable elongation at break (ca. 115%), but greatly improved yielding strength (83 MPa) and O2 gas Barrier property (4.8 times). As modified PEF materials possessing superior thermo-mechanical and O2 gas Barrier properties, these integrally biobased copolyesters may find practical applications in eco-packaging and other fields.
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Modification of Poly(ethylene 2,5-furandicarboxylate) with Biobased 1,5-Pentanediol: Significantly Toughened Copolyesters Retaining High Tensile Strength and O2 Barrier Property
2018Co-Authors: Hongzhou Xie, Philippe DuboisAbstract:Poly(ethylene 2,5-furandicarboxylate) (PEF) is a biobased polyester characterized by high gas Barrier properties as well as high tensile modulus and strength, but poor toughness. Toughening PEF without sacrificing its modulus, strength and gas Barrier Performance is a great challenge for PEF modification. In this study, high molecular weight random poly(ethylene-co-1,5-pentylene 2,5-furandicarboxylate)s (PEPeFs) were synthesized via melt copolycondensation of 2,5-furandicarboxylic acid (FDCA), ethylene glycol (EG) and 1,5-pentanediol (PeDO), a cheap, biobased and commercially available odd-carbon comonomer. The synthesized PEPeFs were characterized and assessed with intrinsic viscosity, ATR-FTIR, 1H NMR, DSC, TGA and tensile, impact and O2 permeation test. Mayo–Lewis equation with “reactivity ratio” of 3.78 for PeDO and 0.75 for EG could be used as an empirical equation to correlate the copolyester composition (ϕPeF) with monomer composition. PEPeFs proved nearly amorphous copolyesters having excellent thermal stability. Brittle–ductile transition was achieved at ϕPeF as low as 9 mol %. Increasing ϕPeF led to increase in elongation at break and notch impact strength and decrease in Tg, O2 Barrier Performance and tensile modulus and strength. However, in comparison with PEF, PEF-rich PEPeFs (ϕPeF 9–47%) not only showed greatly improved elongation at break (29–265% vs 4%) and enhanced impact strength (2.2–3.9 kJ/m2) but also retained very high Young’s modulus (2.8–3.3 vs 3.3 GPa) and yielding strength (72–83 vs 82 MPa). Particularly, when compared with bottle-grade PET, PE82Pe18F possesses equal Tg (ca. 75 °C) and comparable elongation at break (ca. 115%), but greatly improved yielding strength (83 MPa) and O2 gas Barrier property (4.8 times). As modified PEF materials possessing superior thermo-mechanical and O2 gas Barrier properties, these integrally biobased copolyesters may find practical applications in eco-packaging and other fields
Hongzhou Xie - One of the best experts on this subject based on the ideXlab platform.
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modification of poly ethylene 2 5 furandicarboxylate with biobased 1 5 pentanediol significantly toughened copolyesters retaining high tensile strength and o2 Barrier property
Biomacromolecules, 2019Co-Authors: Hongzhou Xie, Philippe DuboisAbstract:Poly(ethylene 2,5-furandicarboxylate) (PEF) is a biobased polyester characterized by high gas Barrier properties as well as high tensile modulus and strength, but poor toughness. Toughening PEF without sacrificing its modulus, strength and gas Barrier Performance is a great challenge for PEF modification. In this study, high molecular weight random poly(ethylene- co-1,5-pentylene 2,5-furandicarboxylate)s (PEPeFs) were synthesized via melt copolycondensation of 2,5-furandicarboxylic acid (FDCA), ethylene glycol (EG) and 1,5-pentanediol (PeDO), a cheap, biobased and commercially available odd-carbon comonomer. The synthesized PEPeFs were characterized and assessed with intrinsic viscosity, ATR-FTIR, 1H NMR, DSC, TGA and tensile, impact and O2 permeation test. Mayo-Lewis equation with "reactivity ratio" of 3.78 for PeDO and 0.75 for EG could be used as an empirical equation to correlate the copolyester composition (ϕPeF) with monomer composition. PEPeFs proved nearly amorphous copolyesters having excellent thermal stability. Brittle-ductile transition was achieved at ϕPeF as low as 9 mol %. Increasing ϕPeF led to increase in elongation at break and notch impact strength and decrease in Tg, O2 Barrier Performance and tensile modulus and strength. However, in comparison with PEF, PEF-rich PEPeFs (ϕPeF 9-47%) not only showed greatly improved elongation at break (29-265% vs 4%) and enhanced impact strength (2.2-3.9 kJ/m2) but also retained very high Young's modulus (2.8-3.3 vs 3.3 GPa) and yielding strength (72-83 vs 82 MPa). Particularly, when compared with bottle-grade PET, PE82Pe18F possesses equal Tg (ca. 75 °C) and comparable elongation at break (ca. 115%), but greatly improved yielding strength (83 MPa) and O2 gas Barrier property (4.8 times). As modified PEF materials possessing superior thermo-mechanical and O2 gas Barrier properties, these integrally biobased copolyesters may find practical applications in eco-packaging and other fields.
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Modification of Poly(ethylene 2,5-furandicarboxylate) with Biobased 1,5-Pentanediol: Significantly Toughened Copolyesters Retaining High Tensile Strength and O2 Barrier Property
2018Co-Authors: Hongzhou Xie, Philippe DuboisAbstract:Poly(ethylene 2,5-furandicarboxylate) (PEF) is a biobased polyester characterized by high gas Barrier properties as well as high tensile modulus and strength, but poor toughness. Toughening PEF without sacrificing its modulus, strength and gas Barrier Performance is a great challenge for PEF modification. In this study, high molecular weight random poly(ethylene-co-1,5-pentylene 2,5-furandicarboxylate)s (PEPeFs) were synthesized via melt copolycondensation of 2,5-furandicarboxylic acid (FDCA), ethylene glycol (EG) and 1,5-pentanediol (PeDO), a cheap, biobased and commercially available odd-carbon comonomer. The synthesized PEPeFs were characterized and assessed with intrinsic viscosity, ATR-FTIR, 1H NMR, DSC, TGA and tensile, impact and O2 permeation test. Mayo–Lewis equation with “reactivity ratio” of 3.78 for PeDO and 0.75 for EG could be used as an empirical equation to correlate the copolyester composition (ϕPeF) with monomer composition. PEPeFs proved nearly amorphous copolyesters having excellent thermal stability. Brittle–ductile transition was achieved at ϕPeF as low as 9 mol %. Increasing ϕPeF led to increase in elongation at break and notch impact strength and decrease in Tg, O2 Barrier Performance and tensile modulus and strength. However, in comparison with PEF, PEF-rich PEPeFs (ϕPeF 9–47%) not only showed greatly improved elongation at break (29–265% vs 4%) and enhanced impact strength (2.2–3.9 kJ/m2) but also retained very high Young’s modulus (2.8–3.3 vs 3.3 GPa) and yielding strength (72–83 vs 82 MPa). Particularly, when compared with bottle-grade PET, PE82Pe18F possesses equal Tg (ca. 75 °C) and comparable elongation at break (ca. 115%), but greatly improved yielding strength (83 MPa) and O2 gas Barrier property (4.8 times). As modified PEF materials possessing superior thermo-mechanical and O2 gas Barrier properties, these integrally biobased copolyesters may find practical applications in eco-packaging and other fields
Hannes Klumbies - One of the best experts on this subject based on the ideXlab platform.
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thickness dependent Barrier Performance of permeation Barriers made from atomic layer deposited alumina for organic devices
Organic Electronics, 2015Co-Authors: Hannes Klumbies, P Schmidt, Markus Hahnel, Aarti Singh, Uwe Schroeder, Claudia Richter, Thomas Mikolajick, Christoph Hosbach, M Albert, J W BarthaAbstract:Organic devices like organic light emitting diodes (OLEDs) or organic solar cells degrade fast when exposed to ambient air. Hence, thin-films acting as permeation Barriers are needed for their protection. Atomic layer deposition (ALD) is known to be one of the best technologies to reach Barriers with a low defect density at gentle process conditions. As well, ALD is reported to be one of the thinnest Barrier layers, with a critical thickness – defining a continuous Barrier film – as low as 5–10 nm for ALD processed Al2O3. In this work, we investigate the Barrier Performance of Al2O3 films processed by ALD at 80 C with trimethylaluminum and ozone as precursors. The coverage of defects in such films is investigated on a 5 nm thick Al2O3 film, i.e. below the critical thickness, on calcium using atomic force microscopy (AFM). We find for this sub-critical thickness regime that all spots giving raise to water ingress on the 20 � 20 lm 2
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Barrier Performance optimization of atomic layer deposited diffusion Barriers for organic light emitting diodes using x ray reflectivity investigations
Applied Physics Letters, 2013Co-Authors: Aarti Singh, Hannes Klumbies, Christoph Hosbach, M Albert, Lars Mullermeskamp, Karl Leo, Uwe Schroder, Marion Geidel, Martin Knaut, Thomas MikolajickAbstract:The importance of O3 pulse duration for encapsulation of organic light emitting diodes (OLEDs) with ultra thin inorganic atomic layer deposited Al2O3 layers is demonstrated for deposition temperatures of 50 °C. X-ray reflectivity (XRR) measurements show that O3 pulse durations longer than 15 s produce dense and thin Al2O3 layers. Correspondingly, black spot growth is not observed in OLEDs encapsulated with such layers during 91 days of aging under ambient conditions. This implies that XRR can be used as a tool for process optimization of OLED encapsulation layers leading to devices with long lifetimes.
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the effect of Barrier Performance on the lifetime of small molecule organic solar cells
Solar Energy Materials and Solar Cells, 2012Co-Authors: Martin Hermenau, Hannes Klumbies, Sylvio Schubert, John Fahlteich, Lars Mullermeskamp, Karl Leo, Moritz RiedeAbstract:Abstract In this work, we use different encapsulations to protect vacuum-evaporated small molecule organic solar cells with a simple p-i-i-stack for lifetime studies. Our devices use ZnPc and C60 as active materials. Lifetimes (T50) in a range from 300 h for un-encapsulated devices to 4000 h for glass-encapsulated have been observed. We use a model to distinguish between the water vapor transmission rate (WVTR) of the Barrier and an additional WVTR of the aluminum top electrode. For all observed devices a loss of 50% of initial efficiency is observed when 10 mg m −2 water entered the device. The losses are related to a reduction of short circuit current density only, whereas open circuit voltage and fill factor remains unaffected. We relate this to an interaction of the water molecules with C60.
Roland Hauert - One of the best experts on this subject based on the ideXlab platform.
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influence of film structure and composition on diffusion Barrier Performance of siox thin films deposited by pecvd
Surface & Coatings Technology, 2006Co-Authors: A Gruniger, A Bieder, Axel Sonnenfeld, Ph Rudolf Von Rohr, U Muller, Roland HauertAbstract:This study focuses on the oxygen permeability of SiOx thin films on polyethyleneterephtalate (PET) produced by plasma-enhanced chemical vapor deposition (PECVD) from oxygen-diluted hexamethyldisiloxane (HMDSO). The versatile PECVD set-up, equipped with two plasma sources (remote microwave and direct radio frequency), allows the deposition of films with variable morphologies and compositions. The deposits were analyzed by XPS, ellipsometry, and atomic force microscopy (AFM). Curve fitting of the Si 2p peak in X-ray photoelectron spectra (XPS) provided information about the chemical binding states of the silicon atoms. The results clearly show that the oxygen transmission rate (OTR) depends highly on the film structure, whereas the chemical composition has only little effect. In order to achieve the desired dense and smooth film structure, it is necessary to have a high substrate bias, which promotes ion bombardment of the film surface during growth. OTR values down to 0.2 cm 3 (STP) m � 2 day � 1 , corresponding to a Barrier improvement factor of 500, have been achieved. D 2005 Elsevier B.V. All rights reserved.
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influence of film structure and composition on diffusion Barrier Performance of siox thin films deposited by pecvd
Surface & Coatings Technology, 2006Co-Authors: A Gruniger, A Bieder, Axel Sonnenfeld, Ph Rudolf Von Rohr, U Muller, Roland HauertAbstract:Abstract This study focuses on the oxygen permeability of SiOx thin films on polyethyleneterephtalate (PET) produced by plasma-enhanced chemical vapor deposition (PECVD) from oxygen-diluted hexamethyldisiloxane (HMDSO). The versatile PECVD set-up, equipped with two plasma sources (remote microwave and direct radio frequency), allows the deposition of films with variable morphologies and compositions. The deposits were analyzed by XPS, ellipsometry, and atomic force microscopy (AFM). Curve fitting of the Si 2p peak in X-ray photoelectron spectra (XPS) provided information about the chemical binding states of the silicon atoms. The results clearly show that the oxygen transmission rate (OTR) depends highly on the film structure, whereas the chemical composition has only little effect. In order to achieve the desired dense and smooth film structure, it is necessary to have a high substrate bias, which promotes ion bombardment of the film surface during growth. OTR values down to 0.2 cm3 (STP) m− 2 day− 1, corresponding to a Barrier improvement factor of 500, have been achieved.
Thomas Mikolajick - One of the best experts on this subject based on the ideXlab platform.
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thickness dependent Barrier Performance of permeation Barriers made from atomic layer deposited alumina for organic devices
Organic Electronics, 2015Co-Authors: Hannes Klumbies, P Schmidt, Markus Hahnel, Aarti Singh, Uwe Schroeder, Claudia Richter, Thomas Mikolajick, Christoph Hosbach, M Albert, J W BarthaAbstract:Organic devices like organic light emitting diodes (OLEDs) or organic solar cells degrade fast when exposed to ambient air. Hence, thin-films acting as permeation Barriers are needed for their protection. Atomic layer deposition (ALD) is known to be one of the best technologies to reach Barriers with a low defect density at gentle process conditions. As well, ALD is reported to be one of the thinnest Barrier layers, with a critical thickness – defining a continuous Barrier film – as low as 5–10 nm for ALD processed Al2O3. In this work, we investigate the Barrier Performance of Al2O3 films processed by ALD at 80 C with trimethylaluminum and ozone as precursors. The coverage of defects in such films is investigated on a 5 nm thick Al2O3 film, i.e. below the critical thickness, on calcium using atomic force microscopy (AFM). We find for this sub-critical thickness regime that all spots giving raise to water ingress on the 20 � 20 lm 2
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Barrier Performance optimization of atomic layer deposited diffusion Barriers for organic light emitting diodes using x ray reflectivity investigations
Applied Physics Letters, 2013Co-Authors: Aarti Singh, Hannes Klumbies, Christoph Hosbach, M Albert, Lars Mullermeskamp, Karl Leo, Uwe Schroder, Marion Geidel, Martin Knaut, Thomas MikolajickAbstract:The importance of O3 pulse duration for encapsulation of organic light emitting diodes (OLEDs) with ultra thin inorganic atomic layer deposited Al2O3 layers is demonstrated for deposition temperatures of 50 °C. X-ray reflectivity (XRR) measurements show that O3 pulse durations longer than 15 s produce dense and thin Al2O3 layers. Correspondingly, black spot growth is not observed in OLEDs encapsulated with such layers during 91 days of aging under ambient conditions. This implies that XRR can be used as a tool for process optimization of OLED encapsulation layers leading to devices with long lifetimes.
