Star-branched polyamide 6 was prepared via anionic ring-opening polymerization of ε-caprolactam in the presence of a simple benzene-centered trifunctional activator of N,N＇,N＂-trimesoyltricaprolactam. A high polyme...Star-branched polyamide 6 was prepared via anionic ring-opening polymerization of ε-caprolactam in the presence of a simple benzene-centered trifunctional activator of N,N＇,N＂-trimesoyltricaprolactam. A high polymer yields of above 95% were achieved at 160 ℃ for 15 min utilizing ε-caprolactam magnesium bromide as a catalyst. Compared with its linear counterpart, the resultant star-branched polyamide 6 showed smaller relative viscosity （1.51 ）, decreased melting temperature （218 ℃） and lower crystallinity （24.2%）. The specific properties demonstrated the existence of a star-branched structure and provided potential advantages in engineering applications.展开更多
The cyclo-N_(6)anion is a total nitrogen unit with higher nitrogen content than cyclo-N^(-)_(5).However,the low decomposition barrier of cyclo-N_(6)anions hinders its application as a high energy density material(HEDM...The cyclo-N_(6)anion is a total nitrogen unit with higher nitrogen content than cyclo-N^(-)_(5).However,the low decomposition barrier of cyclo-N_(6)anions hinders its application as a high energy density material(HEDM).Using first-principles calculations,we reveal that the covalent components that enhance the interaction between the cyclo-N_(6)anion and the cation can effectively improve the stability of cyclo-N_(6)anions.The actinide metals(Th,Pa,U)are selected as suitable cations.Further electronic structure analysis showed that the charge transfer from the actinide metal to cyclo-N_(6)anions resulted in a strong covalent bond,which promoted the stability of the cyclo-N_(6)anion in the Th(N_(6)),Pa(N_(6)),and U(N_(6))structure.This discovery is helpful for the rational design and synthesis of new HEDMs.展开更多
Two new supramolecular architectures {（HC2O4）2^2- [C6H（18）N2^2＋ C（36）H（36）N（24）O（12）]} 12H2O（1） and{（C6H5SO3）22 [C6H（18）N22＋ C（36）H（36）N（24）O（12）]} 12H2O（2） were synthesized and character...Two new supramolecular architectures {（HC2O4）2^2- [C6H（18）N2^2＋ C（36）H（36）N（24）O（12）]} 12H2O（1） and{（C6H5SO3）22 [C6H（18）N22＋ C（36）H（36）N（24）O（12）]} 12H2O（2） were synthesized and characterized by singlecrystal X-ray diffraction, thermogravimetric analysis and X-ray powder diffraction. Compound 1contains infinite two dimensional（2D） L18（8）14（8）8（4） type anion–water aggregates [（HC2O4）4（H2O）（22）]^4- and results in the construction of sandwich-like three dimensional（3D） networks. In compound 2, honeycomb-like three dimensional（3D） networks are fabricated by one dimensional（1D）＂W＂-like T5（0）A2 type anion–water clusters [（C6H5SO3）（H2O）6]^-. These results indicate that anionic groups play a crucial role in modulating the structures of water clusters with their spatial structure and binding sites. In these two structures, the majority of interactions are O...H and H...H interactions on the Hirshfeld surface, which means that hydrogen bonding and hydrophobic interactions are the dominate drive forces in forming these supramolecular systems.展开更多
Bilayer lipid membranes (BLM) formed from didodecyldimethylammonium bromide were made on the freshly exposed surface of a glassy carbon (GC) and were demonstrated by the ac impedance spectroscopy. The ion channels of ...Bilayer lipid membranes (BLM) formed from didodecyldimethylammonium bromide were made on the freshly exposed surface of a glassy carbon (GC) and were demonstrated by the ac impedance spectroscopy. The ion channels of membrane properties induced by PF -_6 were studied by the cyclic voltammetric methods. Experimental results indicated that the ion channel of BLM was open in the presence of the PF -_6 due to the interaction of PF -_6 with the BLM, while it was switched off in the absence of PF -_6. Because the ion channel behavior was affected by the concentration of PF -_6, a sensor for PF -_6 can be developed.展开更多
基金supported by a grant from the National High Technology Research and Development Program of China(No.2014AA021201)the National Basic Research Program of China(No.2012CB721104)+1 种基金China Postdoctoral Science Foundation(No.2014M551574)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Star-branched polyamide 6 was prepared via anionic ring-opening polymerization of ε-caprolactam in the presence of a simple benzene-centered trifunctional activator of N,N＇,N＂-trimesoyltricaprolactam. A high polymer yields of above 95% were achieved at 160 ℃ for 15 min utilizing ε-caprolactam magnesium bromide as a catalyst. Compared with its linear counterpart, the resultant star-branched polyamide 6 showed smaller relative viscosity （1.51 ）, decreased melting temperature （218 ℃） and lower crystallinity （24.2%）. The specific properties demonstrated the existence of a star-branched structure and provided potential advantages in engineering applications.
基金National Natural Science Foundation of China(No.11805157)Sichuan Provincial Department of Science and Technology Application Fundamental Research,China(No.2017JY0146)+1 种基金China West Normal University Scientific Research Innovation Team Project(No.CXTD2016-2)China West Normal University Talent Research Fund Project(No.CXTD2017-10)。
文摘The cyclo-N_(6)anion is a total nitrogen unit with higher nitrogen content than cyclo-N^(-)_(5).However,the low decomposition barrier of cyclo-N_(6)anions hinders its application as a high energy density material(HEDM).Using first-principles calculations,we reveal that the covalent components that enhance the interaction between the cyclo-N_(6)anion and the cation can effectively improve the stability of cyclo-N_(6)anions.The actinide metals(Th,Pa,U)are selected as suitable cations.Further electronic structure analysis showed that the charge transfer from the actinide metal to cyclo-N_(6)anions resulted in a strong covalent bond,which promoted the stability of the cyclo-N_(6)anion in the Th(N_(6)),Pa(N_(6)),and U(N_(6))structure.This discovery is helpful for the rational design and synthesis of new HEDMs.
基金the financial support by the National Natural Science Foundation of China(Nos.21202037and 21401044)Doctor Fund of Henan University of Technology(No.2013BS066)
文摘Two new supramolecular architectures {（HC2O4）2^2- [C6H（18）N2^2＋ C（36）H（36）N（24）O（12）]} 12H2O（1） and{（C6H5SO3）22 [C6H（18）N22＋ C（36）H（36）N（24）O（12）]} 12H2O（2） were synthesized and characterized by singlecrystal X-ray diffraction, thermogravimetric analysis and X-ray powder diffraction. Compound 1contains infinite two dimensional（2D） L18（8）14（8）8（4） type anion–water aggregates [（HC2O4）4（H2O）（22）]^4- and results in the construction of sandwich-like three dimensional（3D） networks. In compound 2, honeycomb-like three dimensional（3D） networks are fabricated by one dimensional（1D）＂W＂-like T5（0）A2 type anion–water clusters [（C6H5SO3）（H2O）6]^-. These results indicate that anionic groups play a crucial role in modulating the structures of water clusters with their spatial structure and binding sites. In these two structures, the majority of interactions are O...H and H...H interactions on the Hirshfeld surface, which means that hydrogen bonding and hydrophobic interactions are the dominate drive forces in forming these supramolecular systems.
基金ProjectsupportedbytheNationalNaturalScienceFoundationofChina (No .2 9835 12 0 )
文摘Bilayer lipid membranes (BLM) formed from didodecyldimethylammonium bromide were made on the freshly exposed surface of a glassy carbon (GC) and were demonstrated by the ac impedance spectroscopy. The ion channels of membrane properties induced by PF -_6 were studied by the cyclic voltammetric methods. Experimental results indicated that the ion channel of BLM was open in the presence of the PF -_6 due to the interaction of PF -_6 with the BLM, while it was switched off in the absence of PF -_6. Because the ion channel behavior was affected by the concentration of PF -_6, a sensor for PF -_6 can be developed.
