Monooctadecyl maleate, as a polymerizable surfactant, was synthesized by the mono-esterification of maleic anhydride and octadecanol, and was utilized to surface-modify nano-Fe3O4 particles. A polymerizable magnetic f...Monooctadecyl maleate, as a polymerizable surfactant, was synthesized by the mono-esterification of maleic anhydride and octadecanol, and was utilized to surface-modify nano-Fe3O4 particles. A polymerizable magnetic fluid was obtained by directly dispersing modified nano-Fe3O4 particles into styrene monomer, and the polystyrene/nano-Fe3O4 composite was prepared through free radical polymerization of polymerizable magnetic fluid. The structure and dispersion status in different dispersion phases of modified nano-Fe3O4 particles were studied by Fourier transform infrared （FTIR） spectrometry, X-ray diffraction （XRD） and transmission electron microscopy （TEM）, respectively. The experimental results show that the nano-Fe3O4 particles modified by monooctadecyl maleate with the size of about 7-10 nm can be uniformly dispersed into styrene and fixed in the composite during the procedure of polymerization. Thermogravimetric analysis （TGA） and vibrating sample magnetometry （VSM） indicate that the thermal stability of polystyrene/nano-Fe3O4 composite is improved compared to that of pure polystyrene, and the composite is a sort of superparamagnetic materials.展开更多
Cross-linkedβ-cyclodextrin polymer/Fe3O4 composite nanoparticles with core-shell structures were prepared via cross linking reaction on the surface of carboxymethylβ-cyclodextrin（CM-β-CD） modified Fe3O4 nanoparti...Cross-linkedβ-cyclodextrin polymer/Fe3O4 composite nanoparticles with core-shell structures were prepared via cross linking reaction on the surface of carboxymethylβ-cyclodextrin（CM-β-CD） modified Fe3O4 nanoparticles inβ-cyclodextrin alkaline solution by using epichlorohydrin as crosslinking agent.The morphology,structure and magnetic properties of the prepared composite nanoparticles were investigated by transmission electron microscopy（TEM）,Fourier transform infrared（FTIR） spectrometry,X-ray diffraction（XRD） measurement,thermogravimetric analysis（TGA） and Vibrating sample magnetometry （VSM）,respectively.展开更多
Macromolecules are efficient as mechanical transducers for mechanically induced chemical bond cleavage reactions.Although various classes of polymers have been studied as effective mechanical-force transducers for mec...Macromolecules are efficient as mechanical transducers for mechanically induced chemical bond cleavage reactions.Although various classes of polymers have been studied as effective mechanical-force transducers for mechanophores,alternatives to polymer chains,that is,small molecules,have rarely been studied.In this paper,the role of hydrogen bonding as small-molecule mechanical-force transducers for the activation of mechano-responsive molecular units(mechanophores)in the bulk is investigated.The introduction of diarylurea linkage motifs,which are known as strong hydrogen bonding groups,enhances the mechanochemical activation of the fluorescent mechanophore tetraarylsuccinonitrile(TASN)as effectively as the attachment of a typical macromolecular transducer.Electron paramagnetic resonance measurements of mechanically activated TASN with diphenyl urea motifs demonstrate its higher carbon–carbon bond dissociation ratio compared to that of TASN without diphenyl urea motifs.This efficient supramolecular-forcetransducing system represents a new concept in the field of mechanochemistry,namely,the enhancement of mechanochemical bond scission by simply changing the substituents of a mechanophore,even in small molecules.展开更多
基金Funded by the Natural Science Foundation of Guangdong Province (No. 020891)
文摘Monooctadecyl maleate, as a polymerizable surfactant, was synthesized by the mono-esterification of maleic anhydride and octadecanol, and was utilized to surface-modify nano-Fe3O4 particles. A polymerizable magnetic fluid was obtained by directly dispersing modified nano-Fe3O4 particles into styrene monomer, and the polystyrene/nano-Fe3O4 composite was prepared through free radical polymerization of polymerizable magnetic fluid. The structure and dispersion status in different dispersion phases of modified nano-Fe3O4 particles were studied by Fourier transform infrared （FTIR） spectrometry, X-ray diffraction （XRD） and transmission electron microscopy （TEM）, respectively. The experimental results show that the nano-Fe3O4 particles modified by monooctadecyl maleate with the size of about 7-10 nm can be uniformly dispersed into styrene and fixed in the composite during the procedure of polymerization. Thermogravimetric analysis （TGA） and vibrating sample magnetometry （VSM） indicate that the thermal stability of polystyrene/nano-Fe3O4 composite is improved compared to that of pure polystyrene, and the composite is a sort of superparamagnetic materials.
基金financially supported by the Guangdong Natural Science Foundation(No.020891)
文摘Cross-linkedβ-cyclodextrin polymer/Fe3O4 composite nanoparticles with core-shell structures were prepared via cross linking reaction on the surface of carboxymethylβ-cyclodextrin（CM-β-CD） modified Fe3O4 nanoparticles inβ-cyclodextrin alkaline solution by using epichlorohydrin as crosslinking agent.The morphology,structure and magnetic properties of the prepared composite nanoparticles were investigated by transmission electron microscopy（TEM）,Fourier transform infrared（FTIR） spectrometry,X-ray diffraction（XRD） measurement,thermogravimetric analysis（TGA） and Vibrating sample magnetometry （VSM）,respectively.
基金supported by KAKENHI grant 17H01205 (Hideyuki Otsuka)from the Japan Society for the Promotion of Science (JSPS)by JST CREST grant JPMJCR1991 (Japan)support from a JSPS Research Fellowship for Young Scientists (201914764).
文摘Macromolecules are efficient as mechanical transducers for mechanically induced chemical bond cleavage reactions.Although various classes of polymers have been studied as effective mechanical-force transducers for mechanophores,alternatives to polymer chains,that is,small molecules,have rarely been studied.In this paper,the role of hydrogen bonding as small-molecule mechanical-force transducers for the activation of mechano-responsive molecular units(mechanophores)in the bulk is investigated.The introduction of diarylurea linkage motifs,which are known as strong hydrogen bonding groups,enhances the mechanochemical activation of the fluorescent mechanophore tetraarylsuccinonitrile(TASN)as effectively as the attachment of a typical macromolecular transducer.Electron paramagnetic resonance measurements of mechanically activated TASN with diphenyl urea motifs demonstrate its higher carbon–carbon bond dissociation ratio compared to that of TASN without diphenyl urea motifs.This efficient supramolecular-forcetransducing system represents a new concept in the field of mechanochemistry,namely,the enhancement of mechanochemical bond scission by simply changing the substituents of a mechanophore,even in small molecules.
