The Experts below are selected from a list of 51993 Experts worldwide ranked by ideXlab platform
Thomas Bechtold - One of the best experts on this subject based on the ideXlab platform.
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Swelling and dissolution mechanism of Lyocell Fiber in aqueous alkaline solution containing ferric tartaric acid complex
Cellulose, 2010Co-Authors: Hai Vu-manh, Hale Bahar Öztürk, Thomas BechtoldAbstract:Swelling properties of Lyocell Fibers in FeTNa (ferric tartaric acid complex) solutions were studied. Concentrations of Fe and free NaOH in FeTNa were varied, while the ratio between FeCl_3.6H_2O: tartaric acid was kept constant as 1:3.28. The concentration of Fe ion varied from 0.15 to 0.55 M. The free NaOH concentration in FeTNa solutions was chosen as 0.4; 0.8; 1.25; 2.5 and 5 M. Fiber diameter measurements following 2 min of swelling and swelling rate of Lyocell Fiber up to 60 min were studied. Depending on concentration of Fe and free NaOH in FeTNa solutions and Fiber swelling time; swelling, dissolution, disintegration or dramatic swelling were observed. 0.4 and 5 M free NaOH containing FeTNa solutions could only swell the Fiber but could not dissolve it. 2.5 M free NaOH containing FeTNa solutions dissolved the Fiber in a few minutes. FeTNa solutions containing free NaOH concentration from 0.8 to 1.25 M resulted in either dissolution or limited swelling depending on Fe concentration.
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Splitting tendency of cellulosic Fibers – Part 1. The effect of shear force on mechanical stability of swollen Lyocell Fibers
Cellulose, 2006Co-Authors: Hale Bahar Öztürk, Satoko Okubayashi, Thomas BechtoldAbstract:A procedure for splitting of a Lyocell Fiber into a multitude of finer fibrils was developed. Crockmeter, usually used for rub-fastness of colored textiles, was modified and used for obtaining required shear force on swollen Lyocell Fiber. The shear force applied on Fibers, and the concentration of NaOH, which affects swelling degree of Fiber, were shown to be the leading parameters determining split number of Lyocell Fiber. While number of shear cycles was found to be of minor relevance for Fiber splitting, the applied pressure directly influences the number of splitted fibrils. For example, at a pressure of 34.8 kPa, the average split number of Lyocell Fiber in 2.5 M NaOH solution was observed as 15, whereas it was observed as 30 for 47 kPa and 41 for 59.3 kPa. Splitting was not observed above 5 M of NaOH solution. Analyses of Fiber splitting permit new aspects to study inner structure of Lyocell.
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Splitting tendency of cellulosic Fibers. Part 2: Effects of Fiber swelling in alkali solutions
Cellulose, 2006Co-Authors: Hale Bahar Öztürk, Satoko Okubayashi, Thomas BechtoldAbstract:The splitting tendency of Lyocell Fiber in aqueous alkali solutions like KOH, NaOH, LiOH and TMAH was investigated. Up to 5 M concentration of alkali solutions, cation type is important on splitting of Lyocell. Above 5 M concentration, cation type is no more relevant to splitting of Lyocell. At 1 M of alkali solutions, alkali retention value (ARV) and split number increase in the order of KOH
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Fibrillation Tendency of Cellulosic Fibers. Part 2: Effects of Temperature
Cellulose, 2005Co-Authors: Wangsun Zhang, Satoko Okubayashi, Thomas BechtoldAbstract:The influences of temperature, concentration of swelling agents and Fiber materials on the fibrillation tendency in various cellulosic Fibers in aqueous solutions were investigated in terms of fibrillation stability and fibrillation sensitivities to alkali and heat. The fibrillation stability and the fibrillation sensitivity to swelling agents were evaluated with a critical point of fibrillation (CPF_conc.) that is the concentration of the swelling agents where fibrillation begins, and the ratio of initial increase in fibril number to increase in concentration of swelling agent ( I _ i ). The fibrillation sensitivity to heat was estimated with the increase in I _ i against temperature. The CPF_conc. of Lyocell Fiber was 16.7 mol/l water in ethanol/water mixture at 25 °C and decreased to 0 mol/l at 80 °C, indicating acceleration of the fibrillation at higher temperatures. The I _ i of Lyocell was enhanced from 3.50 to 7.57 count l/mol. The CPF_conc. increased in the order of viscose > cross-linked Lyocell > modal > Lyocell while the I _ i decreased in the order of viscose < modal < cross-linked Lyocell < Lyocell at 40 °C. The I _ i of Lyocell Fiber increased to the greatest extent with increase in temperature as compared with the other cellulosic Fibers. Lyocell Fiber has the lowest fibrillation stability and the highest fibrillation sensitivities to alkali and to heat resulting in the highest fibrillation tendency.
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Fibrillation Tendency of Cellulosic Fibers. Part 1: Effects of Swelling
Cellulose, 2005Co-Authors: Wangsun Zhang, Satoko Okubayashi, Thomas BechtoldAbstract:The fibrillation tendencies of various cellulosic Fibers in aqueous solution containing alkali metal hydroxide and ethanol were evaluated with two specific parameters: the critical point of fibrillation (CPF_conc.), that is a concentration of swelling agent where the fibrillation begins, and the ratio of initial increase in fibril number to increase in concentration of swelling agent ( I _ i ). The CPF_conc. and the I _ i are defined as fibrillation stability and fibrillation sensitivity to swelling agent, respectively. Lyocell Fiber (CLY1) has the smallest CPF_conc. and the largest I _ i , representing the lowest fibrillation stability and the highest fibrillation sensitivity, leading to the highest fibrillation tendency in CLY1 among the Fibers tested. Although crosslinking improved fibrillation stability in Lyocell as compared to modal, the fibrillation stability remained higher owing to the high water capacity and the high affinity for alkali. In alkali solution at the same concentration CLY1 fibrillation increased in the order of LiOH > NaOH > KOH. However, the plot of fibril number against solvent retention value of CLY1 in different alkaline solutions gives a slope of 110 count · g/cm^3 regardless of alkali type, the critical degree of swelling for CLY1 with no fibrillation was 0.62 cm^3/g in alkali solutions and 0.45 cm^3/g in ethanol/water mixture.
Satoko Okubayashi - One of the best experts on this subject based on the ideXlab platform.
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Splitting tendency of cellulosic Fibers. Part 2: Effects of Fiber swelling in alkali solutions
Cellulose, 2006Co-Authors: Hale Bahar Öztürk, Satoko Okubayashi, Thomas BechtoldAbstract:The splitting tendency of Lyocell Fiber in aqueous alkali solutions like KOH, NaOH, LiOH and TMAH was investigated. Up to 5 M concentration of alkali solutions, cation type is important on splitting of Lyocell. Above 5 M concentration, cation type is no more relevant to splitting of Lyocell. At 1 M of alkali solutions, alkali retention value (ARV) and split number increase in the order of KOH
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Splitting tendency of cellulosic Fibers – Part 1. The effect of shear force on mechanical stability of swollen Lyocell Fibers
Cellulose, 2006Co-Authors: Hale Bahar Öztürk, Satoko Okubayashi, Thomas BechtoldAbstract:A procedure for splitting of a Lyocell Fiber into a multitude of finer fibrils was developed. Crockmeter, usually used for rub-fastness of colored textiles, was modified and used for obtaining required shear force on swollen Lyocell Fiber. The shear force applied on Fibers, and the concentration of NaOH, which affects swelling degree of Fiber, were shown to be the leading parameters determining split number of Lyocell Fiber. While number of shear cycles was found to be of minor relevance for Fiber splitting, the applied pressure directly influences the number of splitted fibrils. For example, at a pressure of 34.8 kPa, the average split number of Lyocell Fiber in 2.5 M NaOH solution was observed as 15, whereas it was observed as 30 for 47 kPa and 41 for 59.3 kPa. Splitting was not observed above 5 M of NaOH solution. Analyses of Fiber splitting permit new aspects to study inner structure of Lyocell.
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splitting tendency of cellulosic Fibers part 1 the effect of shear force on mechanical stability of swollen Lyocell Fibers
Cellulose, 2006Co-Authors: Hale Baha Ozturk, Satoko Okubayashi, Thomas EchtoldAbstract:A procedure for splitting of a Lyocell Fiber into a multitude of finer fibrils was developed. Crockmeter, usually used for rub-fastness of colored textiles, was modified and used for obtaining required shear force on swollen Lyocell Fiber. The shear force applied on Fibers, and the concentration of NaOH, which affects swelling degree of Fiber, were shown to be the leading parameters determining split number of Lyocell Fiber. While number of shear cycles was found to be of minor relevance for Fiber splitting, the applied pressure directly influences the number of splitted fibrils. For example, at a pressure of 34.8 kPa, the average split number of Lyocell Fiber in 2.5 M NaOH solution was observed as 15, whereas it was observed as 30 for 47 kPa and 41 for 59.3 kPa. Splitting was not observed above 5 M of NaOH solution. Analyses of Fiber splitting permit new aspects to study inner structure of Lyocell.
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Fibrillation Tendency of Cellulosic Fibers. Part 2: Effects of Temperature
Cellulose, 2005Co-Authors: Wangsun Zhang, Satoko Okubayashi, Thomas BechtoldAbstract:The influences of temperature, concentration of swelling agents and Fiber materials on the fibrillation tendency in various cellulosic Fibers in aqueous solutions were investigated in terms of fibrillation stability and fibrillation sensitivities to alkali and heat. The fibrillation stability and the fibrillation sensitivity to swelling agents were evaluated with a critical point of fibrillation (CPF_conc.) that is the concentration of the swelling agents where fibrillation begins, and the ratio of initial increase in fibril number to increase in concentration of swelling agent ( I _ i ). The fibrillation sensitivity to heat was estimated with the increase in I _ i against temperature. The CPF_conc. of Lyocell Fiber was 16.7 mol/l water in ethanol/water mixture at 25 °C and decreased to 0 mol/l at 80 °C, indicating acceleration of the fibrillation at higher temperatures. The I _ i of Lyocell was enhanced from 3.50 to 7.57 count l/mol. The CPF_conc. increased in the order of viscose > cross-linked Lyocell > modal > Lyocell while the I _ i decreased in the order of viscose < modal < cross-linked Lyocell < Lyocell at 40 °C. The I _ i of Lyocell Fiber increased to the greatest extent with increase in temperature as compared with the other cellulosic Fibers. Lyocell Fiber has the lowest fibrillation stability and the highest fibrillation sensitivities to alkali and to heat resulting in the highest fibrillation tendency.
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Fibrillation Tendency of Cellulosic Fibers. Part 1: Effects of Swelling
Cellulose, 2005Co-Authors: Wangsun Zhang, Satoko Okubayashi, Thomas BechtoldAbstract:The fibrillation tendencies of various cellulosic Fibers in aqueous solution containing alkali metal hydroxide and ethanol were evaluated with two specific parameters: the critical point of fibrillation (CPF_conc.), that is a concentration of swelling agent where the fibrillation begins, and the ratio of initial increase in fibril number to increase in concentration of swelling agent ( I _ i ). The CPF_conc. and the I _ i are defined as fibrillation stability and fibrillation sensitivity to swelling agent, respectively. Lyocell Fiber (CLY1) has the smallest CPF_conc. and the largest I _ i , representing the lowest fibrillation stability and the highest fibrillation sensitivity, leading to the highest fibrillation tendency in CLY1 among the Fibers tested. Although crosslinking improved fibrillation stability in Lyocell as compared to modal, the fibrillation stability remained higher owing to the high water capacity and the high affinity for alkali. In alkali solution at the same concentration CLY1 fibrillation increased in the order of LiOH > NaOH > KOH. However, the plot of fibril number against solvent retention value of CLY1 in different alkaline solutions gives a slope of 110 count · g/cm^3 regardless of alkali type, the critical degree of swelling for CLY1 with no fibrillation was 0.62 cm^3/g in alkali solutions and 0.45 cm^3/g in ethanol/water mixture.
Thomas Echtold - One of the best experts on this subject based on the ideXlab platform.
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splitting tendency of cellulosic Fibers part 1 the effect of shear force on mechanical stability of swollen Lyocell Fibers
Cellulose, 2006Co-Authors: Hale Baha Ozturk, Satoko Okubayashi, Thomas EchtoldAbstract:A procedure for splitting of a Lyocell Fiber into a multitude of finer fibrils was developed. Crockmeter, usually used for rub-fastness of colored textiles, was modified and used for obtaining required shear force on swollen Lyocell Fiber. The shear force applied on Fibers, and the concentration of NaOH, which affects swelling degree of Fiber, were shown to be the leading parameters determining split number of Lyocell Fiber. While number of shear cycles was found to be of minor relevance for Fiber splitting, the applied pressure directly influences the number of splitted fibrils. For example, at a pressure of 34.8 kPa, the average split number of Lyocell Fiber in 2.5 M NaOH solution was observed as 15, whereas it was observed as 30 for 47 kPa and 41 for 59.3 kPa. Splitting was not observed above 5 M of NaOH solution. Analyses of Fiber splitting permit new aspects to study inner structure of Lyocell.
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fibrillation tendency of cellulosic Fibers part 3 effects of alkali pretreatment of Lyocell Fiber
Carbohydrate Polymers, 2005Co-Authors: Wangsu Zhang, Satoko Okubayashi, Thomas EchtoldAbstract:Abstract The influences of pretreatments with different alkalis on the fibrillation tendency of Lyocell Fiber were investigated. The fibril number (FN pre ) decreased after pretreatment in aqueous sodium hydroxide (NaOH) and potassium hydroxide (KOH) solutions at concentrations between 3.0 and 7.0 mol/l, and minimized at 5.0 mol/l. The water retention value of the Fiber after the pretreatment (WRV pre ) in NaOH and KOH at the concentration where the FN pre was minimized was 0.66 cm 3 /g. Contrarily, the FN pre with trimethylammonium hydroxide (TMAH) increases with increasing the concentration and weight loss. Analysis using scanning electron microscope suggested the uniform reorganization of the macrofibrils of the Lyocell Fiber treated with 5.0 mol/l of NaOH solution while the pretreatment in TMAH and LiOH led to the uneven reorganization, resulting in the acceleration of fibrillation. The results indicate that the fibrillation of Lyocell Fiber is retarded when the Fiber structure is uniformly reorganized without the high loss of cellulose component.
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a kinetic study of moisture sorption and desorption on Lyocell Fibers
Carbohydrate Polymers, 2004Co-Authors: Satoko Okubayashi, Ulrich J Griesse, Thomas EchtoldAbstract:Abstract Dynamic water vapor sorption on Lyocell and cotton Fibers was gravimetrically investigated at 20 °C. Lyocell Fiber showed a higher equilibrium moisture regain of 9.23% w/w at 60% relative humidity compared to 5.54% w/w for the cotton. The hysteresis between the sorption and desorption isotherms for Lyocell was 46.9% and higher than 24.7% for cotton. The hysteresis decreased with increasing relative humidity of the atmosphere. A good fit of the experimental data with the parallel exponential kinetics model suggests that moisture exchange on Lyocell and on cotton is based on two different mechanisms. The kinetic parameters for the identified components of slow and fast sorption were estimated from the simulations and moreover the BET surface volume was calculated. The mechanism of water vapor sorption on cellulosic Fibers are discussed considering the effects of the relative humidity on the kinetic parameters, water retention capacity, BET surface volume and the hysteresis effect.
Hale Bahar Öztürk - One of the best experts on this subject based on the ideXlab platform.
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Swelling and dissolution mechanism of Lyocell Fiber in aqueous alkaline solution containing ferric tartaric acid complex
Cellulose, 2010Co-Authors: Hai Vu-manh, Hale Bahar Öztürk, Thomas BechtoldAbstract:Swelling properties of Lyocell Fibers in FeTNa (ferric tartaric acid complex) solutions were studied. Concentrations of Fe and free NaOH in FeTNa were varied, while the ratio between FeCl_3.6H_2O: tartaric acid was kept constant as 1:3.28. The concentration of Fe ion varied from 0.15 to 0.55 M. The free NaOH concentration in FeTNa solutions was chosen as 0.4; 0.8; 1.25; 2.5 and 5 M. Fiber diameter measurements following 2 min of swelling and swelling rate of Lyocell Fiber up to 60 min were studied. Depending on concentration of Fe and free NaOH in FeTNa solutions and Fiber swelling time; swelling, dissolution, disintegration or dramatic swelling were observed. 0.4 and 5 M free NaOH containing FeTNa solutions could only swell the Fiber but could not dissolve it. 2.5 M free NaOH containing FeTNa solutions dissolved the Fiber in a few minutes. FeTNa solutions containing free NaOH concentration from 0.8 to 1.25 M resulted in either dissolution or limited swelling depending on Fe concentration.
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Splitting tendency of cellulosic Fibers – Part 1. The effect of shear force on mechanical stability of swollen Lyocell Fibers
Cellulose, 2006Co-Authors: Hale Bahar Öztürk, Satoko Okubayashi, Thomas BechtoldAbstract:A procedure for splitting of a Lyocell Fiber into a multitude of finer fibrils was developed. Crockmeter, usually used for rub-fastness of colored textiles, was modified and used for obtaining required shear force on swollen Lyocell Fiber. The shear force applied on Fibers, and the concentration of NaOH, which affects swelling degree of Fiber, were shown to be the leading parameters determining split number of Lyocell Fiber. While number of shear cycles was found to be of minor relevance for Fiber splitting, the applied pressure directly influences the number of splitted fibrils. For example, at a pressure of 34.8 kPa, the average split number of Lyocell Fiber in 2.5 M NaOH solution was observed as 15, whereas it was observed as 30 for 47 kPa and 41 for 59.3 kPa. Splitting was not observed above 5 M of NaOH solution. Analyses of Fiber splitting permit new aspects to study inner structure of Lyocell.
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Splitting tendency of cellulosic Fibers. Part 2: Effects of Fiber swelling in alkali solutions
Cellulose, 2006Co-Authors: Hale Bahar Öztürk, Satoko Okubayashi, Thomas BechtoldAbstract:The splitting tendency of Lyocell Fiber in aqueous alkali solutions like KOH, NaOH, LiOH and TMAH was investigated. Up to 5 M concentration of alkali solutions, cation type is important on splitting of Lyocell. Above 5 M concentration, cation type is no more relevant to splitting of Lyocell. At 1 M of alkali solutions, alkali retention value (ARV) and split number increase in the order of KOH
Mikael Skrifvars - One of the best experts on this subject based on the ideXlab platform.
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Processing of Lyocell Fiber Mat: An Alternative Renewable Reinforcement in Composite Manufacturing
Green and Sustainable Chemistry, 2015Co-Authors: Kayode Adekunle, Mikael SkrifvarsAbstract:The carding of the Lyocell cellulose Fiber was done with a cylindrical cross lap machine supplied by Cormatex Prato, Italy. Several mats were made by carding and needle punching in order to have a compact and well entangled mat suitable for reinforcement. The speed of the cross lap machine, the frequency of needle punching, the number of times the mat goes through needle punching, the feeding rate of the carded Fiber and the depth of needle penetration determined the level of entanglement of the Lyocell Fiber which ultimately increased the mechanical properties of the Fiber. The good mechanical properties of the carded Lyocell Fiber made it a renewable and environmentally friendly alternative as reinforcement in composite manufacturing. Compared with other jute Fiber reinforced composites, the mechanical properties of the resulting Lyocell composites were found to be better. Regenerated cellulose Fiber (Lyocell) composites were environmentally friendly and the mechanical properties were comparable to those of natural Fibers.
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Mechanical properties of renewable soyean oil thermoset reinforced with jute fabricsand Lyocell Fiber
2015Co-Authors: Kayode Adekunle, Christian Patzelt, Adib Kalantar, Mikael SkrifvarsAbstract:Mechanical properties of renewable soyean oil thermoset reinforced with jute fabricsand Lyocell Fiber
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Impact and flexural properties of flax fabrics and Lyocell Fiber reinforced bio-based thermoset for automotive and structural applications
2015Co-Authors: Kayode Adekunle, Sungwoo Cho, Christian Patzelt, Thomas O. J. Blomfeldt, Mikael SkrifvarsAbstract:A bio-based thermoset resin was reinforced with flax fabrics and Lyocell Fiber. The effect of different weave architecture was studied with four flax fabrics with different architecture: plain, twill (two different types) and dobby. The effect of the outer ply thickness was studied and characterized with flexural and impact testing. Composites manufactured with plain weave reinforcement had the best mechanical properties. The tensile strength, tensile modulus, flexural strength, flexural modulus and impact strength was 280 MPa, 32 GPa, 250 MPa, 25 GPa and 75 kJ/m2 respectively.
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mechanical and viscoelastic properties of soybean oil thermoset reinforced with jute fabrics and carded Lyocell Fiber
Journal of Applied Polymer Science, 2011Co-Authors: Kayode Adekunle, Christia Patzel, Adib Kalanta, Mikael SkrifvarsAbstract:Composites and hybrid composites were manufactured from renewable materials based on jute Fibers, regenerated cellulose Fibers (Lyocell), and thermosetting polymer from soybean oil. Three different ...
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impact and flexural properties of flax fabrics and Lyocell Fiber reinforced bio based thermoset
Journal of Reinforced Plastics and Composites, 2011Co-Authors: Kayode Adekunle, Christia Patzel, Sungwoo Cho, Thomas O J Lomfeld, Mikael SkrifvarsAbstract:A bio-based thermoset resin was reinforced with flax fabrics and Lyocell Fiber. The effect of different weave architectures was studied with four flax fabrics with different architectures: plain, t ...
