Catalyst-free copolymerization of ethyl diazoacetate（EDA） with carbethoxycarbene（CEC） has been achieved through two approaches：microwave irradiation and enzyme-assisted（Novozyme-435）system.The structure of the ...Catalyst-free copolymerization of ethyl diazoacetate（EDA） with carbethoxycarbene（CEC） has been achieved through two approaches：microwave irradiation and enzyme-assisted（Novozyme-435）system.The structure of the copolymer was characterized by MALDI-TOF MS（m/z from 2000 to 2450）,which suggested that the main chain of the copolymer consisted of-CH（COOEt）- and-N=NCH（COOEt）- frameworks.Fourier transform infrared（FT1R） spectrometry,elemental analysis,and Raman spectrometry proved the incorporation of azo group in the copolymer.The results indicated that the CEC radicals were generated under microwave irradiation（with or without Novozyme-435） from EDA.The mechanism study described that the generation speed of CEC radical was faster than its polymerization,and the excess CEC radicals improved the activity of the N2C1 group,thus inducing some EDA molecules as radicals.The two kinds of radicals co-coupled to result in poIy（CEC-co-EDA） through the C1/N2C1 copolymerization,but the homopolymerization of CEC radical occurred quicker than its cocoupling with activated EDA.展开更多
The present work reports the irradiation induced grafting polymerization onto nano-sized CaCO3 particles, mainly focusing on the effects of pretreatment with silane coupling agent. It is proved that poly(butyl acrylat...The present work reports the irradiation induced grafting polymerization onto nano-sized CaCO3 particles, mainly focusing on the effects of pretreatment with silane coupling agent. It is proved that poly(butyl acrylate) can be grafted onto the nanoparticles using the technical route suggested by the authors, and the silane treatment of the nanoparticles promotes the grafting polymerization.展开更多
Multi-bond network（MBN） which contains a single network with hierarchical cross-links is a suggested way to fabricate robust hydrogels. In order to reveal the roles of different cross-links with hierarchical bond en...Multi-bond network（MBN） which contains a single network with hierarchical cross-links is a suggested way to fabricate robust hydrogels. In order to reveal the roles of different cross-links with hierarchical bond energy in the MBN, here we fabricate poly（acrylic acid） physical hydrogels with dual bond network composed of ionic cross-links between carboxylFe3＋ interactions and hydrogen bonds, and compare these dually cross-linked hydrogels with singly and ternarily cross-linked hydrogels. Simple models are employed to predict the tensile property, and the results confirm that the multi-bond network with hierarchical distribution in the bond energy of cross-links endows hydrogel with effective energy-dissipating mechanism. Moreover, the dually cross-linked MBN gels exhibit excellent mechanical properties（tensile strength up to 500 k Pa, elongation at break ~ 2400%） and complete self-healing after being kept at 50 °C for 48 h. The factors on promoting self-healing are deeply explored and the dynamic multi-bonds are regarded to trigger the self-healing along with the mutual diffusion of long polymer chains and ferric ions.展开更多
The microstructure modifications of sodium silicate glass induced by 1.2-MeV electron irradiation are studied by x-ray photoelectron spectroscopy and Raman spectroscopy. Depth profile analyses are also performed on th...The microstructure modifications of sodium silicate glass induced by 1.2-MeV electron irradiation are studied by x-ray photoelectron spectroscopy and Raman spectroscopy. Depth profile analyses are also performed on the irradiated glass at 109 Gy. A sodium-depleted layer with a thickness of a few tens of nanometers and the corresponding increase of network polymerization on the top surface are observed after electron bombardment, while the polymerization in the subsurface region has a negligible variation with the irradiation dose. Moreover, the formation of molecular oxygen after electron irradiation is evidenced, which is mainly aggregated in the first two-micron-thick irradiated glass surface. These modifications are correlated to the network relaxation process as a consequence of the diffusion and desorption of sodium species during electron irradiation.展开更多
α-Eleostearic acid and β-eleostearic acid formed vesicles in aqueous medium when an ethanol solution of eleostearic acid was injected rapidly into a vigorously vortexed aqueous phase. Formation of the vesicles was d...α-Eleostearic acid and β-eleostearic acid formed vesicles in aqueous medium when an ethanol solution of eleostearic acid was injected rapidly into a vigorously vortexed aqueous phase. Formation of the vesicles was demonstrated by electron microscopic observation and bromothymol blue encapsulation experiments. Polymerizations of the eleostearic acids in the formed vesicles carried out by UV irradiation produced poly-α-eleostearic acid and poly-β-eleostearic acid vesicles.展开更多
基金supported by the National Natural Science Foundation of China(Nos.21074097 and 21274112)
文摘Catalyst-free copolymerization of ethyl diazoacetate（EDA） with carbethoxycarbene（CEC） has been achieved through two approaches：microwave irradiation and enzyme-assisted（Novozyme-435）system.The structure of the copolymer was characterized by MALDI-TOF MS（m/z from 2000 to 2450）,which suggested that the main chain of the copolymer consisted of-CH（COOEt）- and-N=NCH（COOEt）- frameworks.Fourier transform infrared（FT1R） spectrometry,elemental analysis,and Raman spectrometry proved the incorporation of azo group in the copolymer.The results indicated that the CEC radicals were generated under microwave irradiation（with or without Novozyme-435） from EDA.The mechanism study described that the generation speed of CEC radical was faster than its polymerization,and the excess CEC radicals improved the activity of the N2C1 group,thus inducing some EDA molecules as radicals.The two kinds of radicals co-coupled to result in poIy（CEC-co-EDA） through the C1/N2C1 copolymerization,but the homopolymerization of CEC radical occurred quicker than its cocoupling with activated EDA.
基金The financial supports by the National Natural Science Foundation of China(Grant:50133020.50273047)the Team Project of the Natural Science Foundation of Guangdong.China(Grant:20003038)the Key Program of the Science and Technology Department of Guangdong,China(Grant:2001A1070201)are acknowledged.
文摘The present work reports the irradiation induced grafting polymerization onto nano-sized CaCO3 particles, mainly focusing on the effects of pretreatment with silane coupling agent. It is proved that poly(butyl acrylate) can be grafted onto the nanoparticles using the technical route suggested by the authors, and the silane treatment of the nanoparticles promotes the grafting polymerization.
基金financially supported by the National Natural Science Foundation of China(Nos.51633003 and 21474058)State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Donghua University(No.LK1404)+1 种基金Tsinghua University Scientific Research Project(No.2014Z22069)State Key Laboratory of Organic-Inorganic Composites,Beijing University of Chemical Technology(No.OIC-201601006)
文摘Multi-bond network（MBN） which contains a single network with hierarchical cross-links is a suggested way to fabricate robust hydrogels. In order to reveal the roles of different cross-links with hierarchical bond energy in the MBN, here we fabricate poly（acrylic acid） physical hydrogels with dual bond network composed of ionic cross-links between carboxylFe3＋ interactions and hydrogen bonds, and compare these dually cross-linked hydrogels with singly and ternarily cross-linked hydrogels. Simple models are employed to predict the tensile property, and the results confirm that the multi-bond network with hierarchical distribution in the bond energy of cross-links endows hydrogel with effective energy-dissipating mechanism. Moreover, the dually cross-linked MBN gels exhibit excellent mechanical properties（tensile strength up to 500 k Pa, elongation at break ~ 2400%） and complete self-healing after being kept at 50 °C for 48 h. The factors on promoting self-healing are deeply explored and the dynamic multi-bonds are regarded to trigger the self-healing along with the mutual diffusion of long polymer chains and ferric ions.
文摘The microstructure modifications of sodium silicate glass induced by 1.2-MeV electron irradiation are studied by x-ray photoelectron spectroscopy and Raman spectroscopy. Depth profile analyses are also performed on the irradiated glass at 109 Gy. A sodium-depleted layer with a thickness of a few tens of nanometers and the corresponding increase of network polymerization on the top surface are observed after electron bombardment, while the polymerization in the subsurface region has a negligible variation with the irradiation dose. Moreover, the formation of molecular oxygen after electron irradiation is evidenced, which is mainly aggregated in the first two-micron-thick irradiated glass surface. These modifications are correlated to the network relaxation process as a consequence of the diffusion and desorption of sodium species during electron irradiation.
基金Project supported by the National Natural Science Foundation of China and Zhong GuanCun Analytical Center.
文摘α-Eleostearic acid and β-eleostearic acid formed vesicles in aqueous medium when an ethanol solution of eleostearic acid was injected rapidly into a vigorously vortexed aqueous phase. Formation of the vesicles was demonstrated by electron microscopic observation and bromothymol blue encapsulation experiments. Polymerizations of the eleostearic acids in the formed vesicles carried out by UV irradiation produced poly-α-eleostearic acid and poly-β-eleostearic acid vesicles.
