Hydrogen-bonded polymer complex fiber of poly(ethylene oxide)(PEO)and poly(acrylic acid)(PAA)shows rubber elasticity in ambient environment,but the fiber has relatively low strength and weak stability.We apply the cat...Hydrogen-bonded polymer complex fiber of poly(ethylene oxide)(PEO)and poly(acrylic acid)(PAA)shows rubber elasticity in ambient environment,but the fiber has relatively low strength and weak stability.We apply the catechol chemistry and metal coordination to stabilize and strengthen the PEO/PAA fiber.PAA is grafted with dopamine(Dopa),and then combines with PEO to prepare fiber.PAA-Dopa in the fiber is crosslinked through oxidation induced dismutation and the metal ions are introduced through coordination.The cross-linking and coordination greatly improve the stability of the fiber against the erosion of alkaline water.Among four different metal coordination fibers,PEO/PAA-Dopa/Cu fiber keeps the excellent extensibility(~1000%)and presents much higher initial modulus(~7 MPa),ultimate strength(~20 MPa),and toughness(~60 MJ/m^(3))than its precursor PEO/PAA fiber.In addition,PEO/PAA-Dopa/Cu fiber shows quick recovery and large energy dissipation ratio compared with the PEO/PAA fiber.The distinct mechanical properties enhancement of the hydrogen-bonded complex fiber is attributed to the synergy of hydrogen bonds,coordination and covalent bond cross-linking.展开更多
A selective electrochemical oxidation was developed under mild condition.Various mono-carbonyl and multi-carbonyl compounds can be prepared from different aromatic hydrocarbons with moderate to excellent yield and sel...A selective electrochemical oxidation was developed under mild condition.Various mono-carbonyl and multi-carbonyl compounds can be prepared from different aromatic hydrocarbons with moderate to excellent yield and selectivity by virtue of this electrochemical oxidation.The produced carbonyl compounds can be further transformed intoα-ketoamides,homoallylic alcohols and oximes in a one-pot reaction.In particular,a series ofα-ketoamides were prepared in a one-pot continuous electrolysis.Mechanistic studies showed that 2,2,2-trifluoroethan-1-ol(TFE)can interact with catalyst species and generate the corresponding hydrogen-bonding complex to enhance the electrochemical oxidation performance.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51973029 and 52273020)Ministry of Education(No.8091B022141).
文摘Hydrogen-bonded polymer complex fiber of poly(ethylene oxide)(PEO)and poly(acrylic acid)(PAA)shows rubber elasticity in ambient environment,but the fiber has relatively low strength and weak stability.We apply the catechol chemistry and metal coordination to stabilize and strengthen the PEO/PAA fiber.PAA is grafted with dopamine(Dopa),and then combines with PEO to prepare fiber.PAA-Dopa in the fiber is crosslinked through oxidation induced dismutation and the metal ions are introduced through coordination.The cross-linking and coordination greatly improve the stability of the fiber against the erosion of alkaline water.Among four different metal coordination fibers,PEO/PAA-Dopa/Cu fiber keeps the excellent extensibility(~1000%)and presents much higher initial modulus(~7 MPa),ultimate strength(~20 MPa),and toughness(~60 MJ/m^(3))than its precursor PEO/PAA fiber.In addition,PEO/PAA-Dopa/Cu fiber shows quick recovery and large energy dissipation ratio compared with the PEO/PAA fiber.The distinct mechanical properties enhancement of the hydrogen-bonded complex fiber is attributed to the synergy of hydrogen bonds,coordination and covalent bond cross-linking.
基金supported by the National Natural Science Foundation of China(21672200,21772185)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB20000000)。
文摘A selective electrochemical oxidation was developed under mild condition.Various mono-carbonyl and multi-carbonyl compounds can be prepared from different aromatic hydrocarbons with moderate to excellent yield and selectivity by virtue of this electrochemical oxidation.The produced carbonyl compounds can be further transformed intoα-ketoamides,homoallylic alcohols and oximes in a one-pot reaction.In particular,a series ofα-ketoamides were prepared in a one-pot continuous electrolysis.Mechanistic studies showed that 2,2,2-trifluoroethan-1-ol(TFE)can interact with catalyst species and generate the corresponding hydrogen-bonding complex to enhance the electrochemical oxidation performance.
