Yuhan Li - Academia.edu (original) (raw)

Papers by Yuhan Li

Research paper thumbnail of Towards high-performance polypropylene and its random copolymer: Insight into toughening mechanism of supercritical carbon dioxide assisted annealing

The Journal of Supercritical Fluids, 2014

Research paper thumbnail of Preparation of expanded graphite/poly (phenylene sulfide) composites with high thermal and electrical conductivity by rotating solid-state premixing and melt processing

Journal of Materials Science, 2013

Research paper thumbnail of ChemInform Abstract: Selective Partial Hydrogenation of Dinitrobenzenes to Nitroanilines Catalyzed by Ru/C

Research paper thumbnail of Preparation and properties of ionic cross-linked sulfonated copolyimide membranes containing pyrimidine groups

Polymers for Advanced Technologies, 2012

Jin, R., Li, Y., Xing, W., Qiu, X., Ji, X. and Gao, L.(2012), Preparation and properties of ionic... more Jin, R., Li, Y., Xing, W., Qiu, X., Ji, X. and Gao, L.(2012), Preparation and properties of ionic cross-linked sulfonated copolyimide membranes containing pyrimidine groups. Polymers for Advanced Technologies, 23: 31–37. doi: 10.1002/pat. 1835

Research paper thumbnail of Processing temperature dependent mechanical response of a thermoplastic elastomer with low hard segment

Research paper thumbnail of Transcrystalline formation and properties of polypropylene on the surface of ramie fiber as induced by shear or dopamine modification

Research paper thumbnail of Novel sulfonated polyimide ionomers by incorporating pyridine functional group in the polymer backbone

Journal of Applied Polymer Science, 2009

A series of sulfonated polyimides (SPIs) containing pyridine ring in the polymer backbone were sy... more A series of sulfonated polyimides (SPIs) containing pyridine ring in the polymer backbone were synthesized by the polycondensation of 1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTDA), 5-(2,6-bis(4-aminophenyl)pyridin-4-yl)-2-methoxy benzene sulfonic acid (SDAM), and 4,4′-diaminodiphenyl ether (ODA). Flexible, transparent, and tough membranes were obtained. Property study revealed that all the membranes displayed high thermal stability with the desulfonation and decomposition temperature higher than 290 and 540°C, respectively, as well as good mechanical property with Young's modulus larger than 1.0 GPa, maximum strength (MS) on a scale of 60–80 MPa, and elongation at break (EB) ranged from 41.79 to 75.17%. More importantly, the new materials exhibited small water uptake and excellent dimensional stability with the highest sulfonated SPI-80 showing the maximum water uptake of 36.1%, and maximum swollen ratio of Δt = 0.038 and Δl = 0.026, respectively (Δt and Δl stands for the thickness and diameter change of the film, respectively). The high water stability exhibited by the SPI films is attributed to the formation of inner salts and/or ionic crosslinking between the sulfonic acid and pyridine functional groups, which suppresses the water uptake ability of sulfonic acid and strengthened the interpolymer chain interactions. Thus, the excellent water stability, good thermal and mechanical properties, and the technologically applicable conductivity of SPI-80 render this material attractive for proton exchange membrane (PEM) application. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Research paper thumbnail of Synthesis and characterization of novel sulfonated polyimides from 1,4-bis(4-aminophenoxy)-naphthyl-2,7-disulfonic acid

Polymer, 2007

A novel sulfonated diamine monomer, 1,4-bis(4-aminophenoxy)-naphthyl-2,7-disulfonic acid (BAPNDS)... more A novel sulfonated diamine monomer, 1,4-bis(4-aminophenoxy)-naphthyl-2,7-disulfonic acid (BAPNDS), was synthesized. A series of sulfonated polyimide copolymers were prepared from BAPNDS, 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA) and nonsulfonated diamine 4,4′-diaminodiphenyl ether (ODA). Flexible, transparent, and mechanically strong membranes were obtained. The membranes displayed slightly anisotropic membrane swelling. The dimensional change in thickness direction was larger than that in planar. The novel SPI membranes showed higher conductivity, which was comparable or even higher than Nafion 117. Membranes exhibited methanol permeability from 0.24 × 10−6 to 0.80 × 10−6 cm2/s at room temperature, which was much lower than that of Nafion (2 × 10−6 cm2/s). The copolymers were thermally stable up to 340 °C. These preliminary results have proved its potential availability as proton-exchange membrane for PEMFCs or DMFCs.

Research paper thumbnail of Synthesis and properties of novel sulfonated polyimides containing binaphthyl groups as proton-exchange membranes for fuel cells

Journal of Polymer Science Part A: Polymer Chemistry, 2007

Research paper thumbnail of Relative Surface Density and Stability of the Amines on the Biochip

Chinese Journal of Analytical Chemistry, 2006

Research paper thumbnail of Selective Partial Hydrogenation of Dinitrobenzenes to Nitroanilines Catalyzed by Ru/C

Chemistry Letters, 2008

Ru/C was found to be a highly effective catalyst for the selective partial hydrogenation of a ran... more Ru/C was found to be a highly effective catalyst for the selective partial hydrogenation of a range of dinitrobenzenes to their corresponding nitroanilines with excellent selectivity under mild conditions. Furthermore, the effect from other substitute groups of dinitrobenzenes on ...

Research paper thumbnail of Towards high-performance polypropylene and its random copolymer: Insight into toughening mechanism of supercritical carbon dioxide assisted annealing

The Journal of Supercritical Fluids, 2014

Research paper thumbnail of Preparation of expanded graphite/poly (phenylene sulfide) composites with high thermal and electrical conductivity by rotating solid-state premixing and melt processing

Journal of Materials Science, 2013

Research paper thumbnail of ChemInform Abstract: Selective Partial Hydrogenation of Dinitrobenzenes to Nitroanilines Catalyzed by Ru/C

Research paper thumbnail of Preparation and properties of ionic cross-linked sulfonated copolyimide membranes containing pyrimidine groups

Polymers for Advanced Technologies, 2012

Jin, R., Li, Y., Xing, W., Qiu, X., Ji, X. and Gao, L.(2012), Preparation and properties of ionic... more Jin, R., Li, Y., Xing, W., Qiu, X., Ji, X. and Gao, L.(2012), Preparation and properties of ionic cross-linked sulfonated copolyimide membranes containing pyrimidine groups. Polymers for Advanced Technologies, 23: 31–37. doi: 10.1002/pat. 1835

Research paper thumbnail of Processing temperature dependent mechanical response of a thermoplastic elastomer with low hard segment

Research paper thumbnail of Transcrystalline formation and properties of polypropylene on the surface of ramie fiber as induced by shear or dopamine modification

Research paper thumbnail of Novel sulfonated polyimide ionomers by incorporating pyridine functional group in the polymer backbone

Journal of Applied Polymer Science, 2009

A series of sulfonated polyimides (SPIs) containing pyridine ring in the polymer backbone were sy... more A series of sulfonated polyimides (SPIs) containing pyridine ring in the polymer backbone were synthesized by the polycondensation of 1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTDA), 5-(2,6-bis(4-aminophenyl)pyridin-4-yl)-2-methoxy benzene sulfonic acid (SDAM), and 4,4′-diaminodiphenyl ether (ODA). Flexible, transparent, and tough membranes were obtained. Property study revealed that all the membranes displayed high thermal stability with the desulfonation and decomposition temperature higher than 290 and 540°C, respectively, as well as good mechanical property with Young's modulus larger than 1.0 GPa, maximum strength (MS) on a scale of 60–80 MPa, and elongation at break (EB) ranged from 41.79 to 75.17%. More importantly, the new materials exhibited small water uptake and excellent dimensional stability with the highest sulfonated SPI-80 showing the maximum water uptake of 36.1%, and maximum swollen ratio of Δt = 0.038 and Δl = 0.026, respectively (Δt and Δl stands for the thickness and diameter change of the film, respectively). The high water stability exhibited by the SPI films is attributed to the formation of inner salts and/or ionic crosslinking between the sulfonic acid and pyridine functional groups, which suppresses the water uptake ability of sulfonic acid and strengthened the interpolymer chain interactions. Thus, the excellent water stability, good thermal and mechanical properties, and the technologically applicable conductivity of SPI-80 render this material attractive for proton exchange membrane (PEM) application. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Research paper thumbnail of Synthesis and characterization of novel sulfonated polyimides from 1,4-bis(4-aminophenoxy)-naphthyl-2,7-disulfonic acid

Polymer, 2007

A novel sulfonated diamine monomer, 1,4-bis(4-aminophenoxy)-naphthyl-2,7-disulfonic acid (BAPNDS)... more A novel sulfonated diamine monomer, 1,4-bis(4-aminophenoxy)-naphthyl-2,7-disulfonic acid (BAPNDS), was synthesized. A series of sulfonated polyimide copolymers were prepared from BAPNDS, 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA) and nonsulfonated diamine 4,4′-diaminodiphenyl ether (ODA). Flexible, transparent, and mechanically strong membranes were obtained. The membranes displayed slightly anisotropic membrane swelling. The dimensional change in thickness direction was larger than that in planar. The novel SPI membranes showed higher conductivity, which was comparable or even higher than Nafion 117. Membranes exhibited methanol permeability from 0.24 × 10−6 to 0.80 × 10−6 cm2/s at room temperature, which was much lower than that of Nafion (2 × 10−6 cm2/s). The copolymers were thermally stable up to 340 °C. These preliminary results have proved its potential availability as proton-exchange membrane for PEMFCs or DMFCs.

Research paper thumbnail of Synthesis and properties of novel sulfonated polyimides containing binaphthyl groups as proton-exchange membranes for fuel cells

Journal of Polymer Science Part A: Polymer Chemistry, 2007

Research paper thumbnail of Relative Surface Density and Stability of the Amines on the Biochip

Chinese Journal of Analytical Chemistry, 2006

Research paper thumbnail of Selective Partial Hydrogenation of Dinitrobenzenes to Nitroanilines Catalyzed by Ru/C

Chemistry Letters, 2008

Ru/C was found to be a highly effective catalyst for the selective partial hydrogenation of a ran... more Ru/C was found to be a highly effective catalyst for the selective partial hydrogenation of a range of dinitrobenzenes to their corresponding nitroanilines with excellent selectivity under mild conditions. Furthermore, the effect from other substitute groups of dinitrobenzenes on ...