The Experts below are selected from a list of 16074 Experts worldwide ranked by ideXlab platform
Jie Yin - One of the best experts on this subject based on the ideXlab platform.
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Dynamic crosslinked poly(styrene-block-butadiene-block-styrene) via Diels–Alder chemistry: an ideal method to improve Solvent Resistance and mechanical properties without losing its thermal plastic behavior
RSC Advances, 2015Co-Authors: Bai Jing, Zixing Shi, Ming Tian, Jie YinAbstract:Poly(styrene-block-butadiene-block-styrene) (SBS) is a typical example of thermal plastic elastomers (TPE). People usually encounter a well-known paradox for SBS, where improving its poor Solvent Resistance and low mechanical properties usually means it suffers from losing its thermal plastic remolding ability, one of most important characters for TPE. In this paper, we propose a novel solution for this problem. SBS was first modified with furan via a thiol–ene reaction and then reacted with bismaleimide to form thermally dynamic reversible crosslinking linkages for SBS via a Diels–Alder reaction. As a result, the dynamic crosslinked SBS could only swell in the toluene with improved Solvent Resistance at ambient temperature. The mechanical properties showed great improvement. As an example, the maximum tensile strength was obtained at 14.96 MPa, increased by almost 8 times in comparison with the pure SBS and the tensile strain was still kept above 800%. More importantly, the crosslinked SBS could still be thermal plastic remolded due to the de-crosslinking reaction via a retro-DA reaction at higher temperature and the mechanical properties still remained almost the same even after 3 generations of remolding. The merits of this modified SBS originate from its dynamic crosslinking network to improve its mechanical properties and Solvent Resistance without sacrificing its thermal plastic remolding ability.
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dynamic crosslinked poly styrene block butadiene block styrene via diels alder chemistry an ideal method to improve Solvent Resistance and mechanical properties without losing its thermal plastic behavior
RSC Advances, 2015Co-Authors: Jing Bai, Zixing Shi, Ming Tian, Jie YinAbstract:Poly(styrene-block-butadiene-block-styrene) (SBS) is a typical example of thermal plastic elastomers (TPE). People usually encounter a well-known paradox for SBS, where improving its poor Solvent Resistance and low mechanical properties usually means it suffers from losing its thermal plastic remolding ability, one of most important characters for TPE. In this paper, we propose a novel solution for this problem. SBS was first modified with furan via a thiol–ene reaction and then reacted with bismaleimide to form thermally dynamic reversible crosslinking linkages for SBS via a Diels–Alder reaction. As a result, the dynamic crosslinked SBS could only swell in the toluene with improved Solvent Resistance at ambient temperature. The mechanical properties showed great improvement. As an example, the maximum tensile strength was obtained at 14.96 MPa, increased by almost 8 times in comparison with the pure SBS and the tensile strain was still kept above 800%. More importantly, the crosslinked SBS could still be thermal plastic remolded due to the de-crosslinking reaction via a retro-DA reaction at higher temperature and the mechanical properties still remained almost the same even after 3 generations of remolding. The merits of this modified SBS originate from its dynamic crosslinking network to improve its mechanical properties and Solvent Resistance without sacrificing its thermal plastic remolding ability.
Pingya Luo - One of the best experts on this subject based on the ideXlab platform.
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Hierarchically Stabilized PAN/β-FeOOH Nanofibrous Membrane for Efficient Water Purification with Excellent Antifouling Performance and Robust Solvent Resistance
ACS Applied Materials & Interfaces, 2019Co-Authors: Liyun Zhang, Jingyu Chen, Yi Fan, Shihong Zhang, Heng Shi, Pingya LuoAbstract:Filtration membranes, with good antifouling performance and robust Solvent Resistance (e.g., organic Solvents or highly acidic/alkaline/saline Solvents), that can effectively purify complex polluted water systems are especially demanded in practice but present a challenge to be conquered. Herein, a simple method has been demonstrated to address the obstacles, applying the stabilized polyacrylonitrile (SPAN) nanofiber/β-FeOOH nanorod composite membrane as a model. In this work, simply stabilizing PAN nanofibers in air can achieve robust Solvent Resistance against organic Solvents and strong inorganic acidic/alkaline/saline solutions. Hydrophilic β-FeOOH nanorods were anchored onto SPAN nanofibers of our electrospun membrane and achieve superhydrophilicity (0°)/underwater superoleophobicity (>155°) for various oils. More importantly, the SPAN/β-FeOOH nanofibrous membrane exhibits robust mechanical strength (274 MPa of Young's modulus), excellent chemical stability, fast separation flux (2532-10146 L m-2 h-1), and satisfying removal ratio (>98.2%) against insoluble oils and soluble cationic dyes. In addition, good photocatalytic activity against organic pollutants provides our membranes with excellent flux restorability and a long-term use capacity. These outstanding performances endow our membrane with a great potential application in purifying polluted aquatic systems in worldly harsh conditions.
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hierarchically stabilized pan β feooh nanofibrous membrane for efficient water purification with excellent antifouling performance and robust Solvent Resistance
ACS Applied Materials & Interfaces, 2019Co-Authors: Liyun Zhang, Jingyu Chen, Yi Fan, Shihong Zhang, Heng Shi, Pingya LuoAbstract:Filtration membranes, with good antifouling performance and robust Solvent Resistance (e.g., organic Solvents or highly acidic/alkaline/saline Solvents), that can effectively purify complex polluted water systems are especially demanded in practice but present a challenge to be conquered. Herein, a simple method has been demonstrated to address the obstacles, applying the stabilized polyacrylonitrile (SPAN) nanofiber/β-FeOOH nanorod composite membrane as a model. In this work, simply stabilizing PAN nanofibers in air can achieve robust Solvent Resistance against organic Solvents and strong inorganic acidic/alkaline/saline solutions. Hydrophilic β-FeOOH nanorods were anchored onto SPAN nanofibers of our electrospun membrane and achieve superhydrophilicity (0°)/underwater superoleophobicity (>155°) for various oils. More importantly, the SPAN/β-FeOOH nanofibrous membrane exhibits robust mechanical strength (274 MPa of Young's modulus), excellent chemical stability, fast separation flux (2532-10146 L m-2 h-1), and satisfying removal ratio (>98.2%) against insoluble oils and soluble cationic dyes. In addition, good photocatalytic activity against organic pollutants provides our membranes with excellent flux restorability and a long-term use capacity. These outstanding performances endow our membrane with a great potential application in purifying polluted aquatic systems in worldly harsh conditions.
Juan L. Ramos - One of the best experts on this subject based on the ideXlab platform.
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Involvement of the cis/trans Isomerase Cti in Solvent Resistance of Pseudomonas putida DOT-T1E
Journal of Bacteriology, 1999Co-Authors: Frank Junker, Juan L. RamosAbstract:Organic Solvents such as toluene, xylene, or styrene are known to damage the bacterial cell membrane and thus to inhibit growth. They bind to and penetrate the lipid bilayer and impair vital membrane functions, leading to loss of ions and metabolites, to dissipation of the pH gradient and electrical potential, and to inhibition of membrane protein functions. The toxicity of the Solvent depends on the logarithm of its partition coefficient in a mixture of octanol and water (log Pow) (37). During the last decade, numerous bacteria belonging mainly to the genus Pseudomonas, with high Resistance to organic Solvents, have been isolated (6, 18, 30, 32, 40). To overcome the damage caused by these Solvents, several adaptive mechanisms which readjust membrane fluidity have been suggested. Among these mechanisms are Solvent efflux pumps (22, 31) and changes in lipopolysaccharide and phospholipid composition (8, 30, 33, 40). The alteration in phospholipid composition includes modifications in the phospholipid headgroup as well as changes in esterified fatty acid composition. There are two major mechanisms involving esterified fatty acids: a shift in the unsaturated/saturated fatty acid ratio, and cis-trans isomerization. The cis-trans modification is considered a short-term response (21) which takes place within 1 min after Solvent exposure, whereas changes in the degree of saturation and phospholipid headgroups are long-term responses which are detected after 15 to 20 min. Additionally, an increase in the total amount of phospholipids was found in response to Solvent exposure (30). cis fatty acids are present in most bacteria, whereas the trans isomers are less widespread. Further details about trans fatty acids in bacteria are given in the review by Keweloh and Heipieper (21). The cis-trans isomerization triggered by Solvent exposure, which occurs without shifts in the position of the double bond of the C16:1,9 and C18:1,11 fatty acids, was shown to be a postsynthetic enzyme modification in Pseudomonas putida P8 (8). The cis-trans isomerase (Cti) in P. putida P8 has recently been cloned and sequenced (accession no. {"type":"entrez-nucleotide","attrs":{"text":"AJ000978","term_id":"2612819","term_text":"AJ000978"}}AJ000978 [15]). We studied the influence of cis-trans isomerization on toluene Resistance in Pseudomonas putida DOT-T1E (31–33), a strain which can grow in the presence of 90% (vol/vol) toluene and use toluene as the sole source of carbon and energy. Toluene causes an increase in membrane fluidity which is counteracted by an elevated level of trans fatty acids and an increase in the content of cardiolipin as the phospholipid headgroup (33). Both changes decrease membrane fluidity. The cis/trans ratio decreases from 7.5 to 1 when cells are grown in the presence of 1% (vol/vol) toluene in Luria-Bertani (LB) medium. In a time course experiment, the level of trans fatty acids increased immediately after exposure to toluene, at the expense of the cis fatty acids. The relative level of cardiolipin was twofold higher in cells growing in the presence of toluene than in cells growing in its absence (33). Toluene efflux pumps were recently identified as playing a major role in toluene Resistance (31), whereas the absence or presence of the metabolic route for toluene degradation had no influence on Solvent Resistance in strain DOT-T1E (26). We now report the cloning, sequencing, and expression of the cis/trans isomerase, Cti, in P. putida DOT-T1E. To evaluate the role of this isomerase in Solvent tolerance, a Cti-null mutant of strain DOT-T1E was generated and physiologically characterized. We found that the mutant was more sensitive than the parent strain to sudden Solvent shock and exhibited delayed growth when exposed to nonlethal concentrations of toluene or high temperatures. We also found that the cti gene was expressed constitutively.
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involvement of the cis trans isomerase cti in Solvent Resistance of pseudomonas putida dot t1e
Journal of Bacteriology, 1999Co-Authors: Frank Junker, Juan L. RamosAbstract:Organic Solvents such as toluene, xylene, or styrene are known to damage the bacterial cell membrane and thus to inhibit growth. They bind to and penetrate the lipid bilayer and impair vital membrane functions, leading to loss of ions and metabolites, to dissipation of the pH gradient and electrical potential, and to inhibition of membrane protein functions. The toxicity of the Solvent depends on the logarithm of its partition coefficient in a mixture of octanol and water (log Pow) (37). During the last decade, numerous bacteria belonging mainly to the genus Pseudomonas, with high Resistance to organic Solvents, have been isolated (6, 18, 30, 32, 40). To overcome the damage caused by these Solvents, several adaptive mechanisms which readjust membrane fluidity have been suggested. Among these mechanisms are Solvent efflux pumps (22, 31) and changes in lipopolysaccharide and phospholipid composition (8, 30, 33, 40). The alteration in phospholipid composition includes modifications in the phospholipid headgroup as well as changes in esterified fatty acid composition. There are two major mechanisms involving esterified fatty acids: a shift in the unsaturated/saturated fatty acid ratio, and cis-trans isomerization. The cis-trans modification is considered a short-term response (21) which takes place within 1 min after Solvent exposure, whereas changes in the degree of saturation and phospholipid headgroups are long-term responses which are detected after 15 to 20 min. Additionally, an increase in the total amount of phospholipids was found in response to Solvent exposure (30). cis fatty acids are present in most bacteria, whereas the trans isomers are less widespread. Further details about trans fatty acids in bacteria are given in the review by Keweloh and Heipieper (21). The cis-trans isomerization triggered by Solvent exposure, which occurs without shifts in the position of the double bond of the C16:1,9 and C18:1,11 fatty acids, was shown to be a postsynthetic enzyme modification in Pseudomonas putida P8 (8). The cis-trans isomerase (Cti) in P. putida P8 has recently been cloned and sequenced (accession no. {"type":"entrez-nucleotide","attrs":{"text":"AJ000978","term_id":"2612819","term_text":"AJ000978"}}AJ000978 [15]). We studied the influence of cis-trans isomerization on toluene Resistance in Pseudomonas putida DOT-T1E (31–33), a strain which can grow in the presence of 90% (vol/vol) toluene and use toluene as the sole source of carbon and energy. Toluene causes an increase in membrane fluidity which is counteracted by an elevated level of trans fatty acids and an increase in the content of cardiolipin as the phospholipid headgroup (33). Both changes decrease membrane fluidity. The cis/trans ratio decreases from 7.5 to 1 when cells are grown in the presence of 1% (vol/vol) toluene in Luria-Bertani (LB) medium. In a time course experiment, the level of trans fatty acids increased immediately after exposure to toluene, at the expense of the cis fatty acids. The relative level of cardiolipin was twofold higher in cells growing in the presence of toluene than in cells growing in its absence (33). Toluene efflux pumps were recently identified as playing a major role in toluene Resistance (31), whereas the absence or presence of the metabolic route for toluene degradation had no influence on Solvent Resistance in strain DOT-T1E (26). We now report the cloning, sequencing, and expression of the cis/trans isomerase, Cti, in P. putida DOT-T1E. To evaluate the role of this isomerase in Solvent tolerance, a Cti-null mutant of strain DOT-T1E was generated and physiologically characterized. We found that the mutant was more sensitive than the parent strain to sudden Solvent shock and exhibited delayed growth when exposed to nonlethal concentrations of toluene or high temperatures. We also found that the cti gene was expressed constitutively.
Jing Bai - One of the best experts on this subject based on the ideXlab platform.
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dynamic crosslinked poly styrene block butadiene block styrene via diels alder chemistry an ideal method to improve Solvent Resistance and mechanical properties without losing its thermal plastic behavior
RSC Advances, 2015Co-Authors: Jing Bai, Zixing Shi, Ming Tian, Jie YinAbstract:Poly(styrene-block-butadiene-block-styrene) (SBS) is a typical example of thermal plastic elastomers (TPE). People usually encounter a well-known paradox for SBS, where improving its poor Solvent Resistance and low mechanical properties usually means it suffers from losing its thermal plastic remolding ability, one of most important characters for TPE. In this paper, we propose a novel solution for this problem. SBS was first modified with furan via a thiol–ene reaction and then reacted with bismaleimide to form thermally dynamic reversible crosslinking linkages for SBS via a Diels–Alder reaction. As a result, the dynamic crosslinked SBS could only swell in the toluene with improved Solvent Resistance at ambient temperature. The mechanical properties showed great improvement. As an example, the maximum tensile strength was obtained at 14.96 MPa, increased by almost 8 times in comparison with the pure SBS and the tensile strain was still kept above 800%. More importantly, the crosslinked SBS could still be thermal plastic remolded due to the de-crosslinking reaction via a retro-DA reaction at higher temperature and the mechanical properties still remained almost the same even after 3 generations of remolding. The merits of this modified SBS originate from its dynamic crosslinking network to improve its mechanical properties and Solvent Resistance without sacrificing its thermal plastic remolding ability.
Biao Yin - One of the best experts on this subject based on the ideXlab platform.
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high mechanical properties thermal conductivity and Solvent Resistance in graphene oxide styrene butadiene rubber nanocomposites by engineering carboxylated acrylonitrile butadiene rubber
Composites Part B-engineering, 2017Co-Authors: Pengzhang Liu, Xumin Zhang, Jingyi Wang, Hongbing Jia, Qing Yin, Biao YinAbstract:Abstract In this paper, graphene oxide (GO) was modified with carboxylated acrylonitrile-butadiene rubber (xNBR) to synthesize the xNBR modified GO (xNBR-GO), which was adopted to reinforce styrene-butadiene rubber (SBR) nanocomposites through latex compounding method. The interaction between GO and xNBR was verified by Fourier transform infrared spectroscopy (FTIR) and Raman spectra. The dispersion of filler and morphology of xNBR-GO/SBR nanocomposites were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The mechanical properties, dynamic mechanical properties, thermal stability, thermal conductivity as well as Solvent Resistance of the xNBR-GO/SBR nanocomposites were also thoroughly studied. It was confirmed that xNBR could interact with GO through hydrogen bonding. The modification would improve the dispersion and reinforcement of filler. With the incorporation of 5 phr (parts per hundred rubber) filler, the tensile strength, tear strength and thermal conductivity of xNBR-GO/SBR nanocomposite were increased by 545%, 351% and 31.7%, respectively. In addition, the equilibrium Solvent uptake was decreased by 31.8%, and the thermal stability was enhanced.
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High mechanical properties, thermal conductivity and Solvent Resistance in graphene oxide/styrene-butadiene rubber nanocomposites by engineering carboxylated acrylonitrile-butadiene rubber
Composites Part B-engineering, 2017Co-Authors: Liu Pengzhang, Xumin Zhang, Jingyi Wang, Hongbing Jia, Qing Yin, Biao YinAbstract:Abstract In this paper, graphene oxide (GO) was modified with carboxylated acrylonitrile-butadiene rubber (xNBR) to synthesize the xNBR modified GO (xNBR-GO), which was adopted to reinforce styrene-butadiene rubber (SBR) nanocomposites through latex compounding method. The interaction between GO and xNBR was verified by Fourier transform infrared spectroscopy (FTIR) and Raman spectra. The dispersion of filler and morphology of xNBR-GO/SBR nanocomposites were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The mechanical properties, dynamic mechanical properties, thermal stability, thermal conductivity as well as Solvent Resistance of the xNBR-GO/SBR nanocomposites were also thoroughly studied. It was confirmed that xNBR could interact with GO through hydrogen bonding. The modification would improve the dispersion and reinforcement of filler. With the incorporation of 5 phr (parts per hundred rubber) filler, the tensile strength, tear strength and thermal conductivity of xNBR-GO/SBR nanocomposite were increased by 545%, 351% and 31.7%, respectively. In addition, the equilibrium Solvent uptake was decreased by 31.8%, and the thermal stability was enhanced.
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Polyvinyl pyrrolidone modified graphene oxide for improving the mechanical, thermal conductivity and Solvent Resistance properties of natural rubber
RSC Advances, 2016Co-Authors: Xumin Zhang, Jingyi Wang, Hongbing Jia, Biao Yin, Lifeng DingAbstract:Polyvinyl pyrrolidone (PVP) was applied to modify graphene oxide (GO) to obtain PVP modified GO (PGO). The PGO/natural rubber (NR) nanocomposites were fabricated by mixing a PGO aqueous dispersion with NR latex, followed by coagulation and vulcanization. The structure of PGO was characterized using atomic force microscopy, solid state 13C NMR, Fourier transform infrared spectroscopy, Raman spectra and X-ray photoelectron spectroscopy. The interaction between GO and PVP molecules as well as the effects of PGO on the mechanical properties, thermal conductivity and Solvent Resistance properties of the NR matrix were thoroughly studied. The results revealed that PVP molecules might interact with GO via hydrogen bonds. With the addition of PGO, the tensile strength, tear strength and thermal conductivity as well as Solvent Resistance of the PGO/NR nanocomposites increased. The PGO/NR nanocomposite with 5 phr (parts per hundred rubber) PGO had an 81%, 159%, 30% increase in tensile strength, tear strength, thermal conductivity and a 46% decrease in Solvent uptake, respectively, compared with pristine NR.
