This paper describes the synthesis and free radical ring-opening polymerization of 2-methyl-and 2-methyl-9-n-butyl (-7-methylene-1, 4, 6-trioxaspiro (4, 4) nonane). The structures of the two polymers were verified by ...This paper describes the synthesis and free radical ring-opening polymerization of 2-methyl-and 2-methyl-9-n-butyl (-7-methylene-1, 4, 6-trioxaspiro (4, 4) nonane). The structures of the two polymers were verified by IR, 'H and ^(13)C NMR spectra. The substituent on 9-position of 7-methylene-trioxaspiro (4, 4) nonane affects the structure of polymer and polymerization activity. The polymerization mechanism is discussed.展开更多
The 2,2-dinitropropyl methacrylate（DNPMA） was synthesized by esterification of α-methacrylic acid with 2,2-dinitropropanol.The free-radical bulk polymerization of DNPMA in the presence of 2,2-azobisisobutyronitrile...The 2,2-dinitropropyl methacrylate（DNPMA） was synthesized by esterification of α-methacrylic acid with 2,2-dinitropropanol.The free-radical bulk polymerization of DNPMA in the presence of 2,2-azobisisobutyronitrile（AIBN） was investigated by differential scanning calorimetry（DSC） in the nonisothermal mode.Kissinger,Ozawa and Barrett methods were applied to determine the activation energy（Ea） and the reaction order of the free-radical polymerization.The results showed that the temperature of exothermic polymerization peaks increased with increasing heating rate.With increasing the molar ratio of monomer/initiator and the heating rate,the reaction order of nonisothermal polymerization was approximately equal to 1.The average Ea value from Kissinger and Ozawa methods（77.74±1.07 kJ/mol） was smaller than the value from the Barrett method（Ea=102.36 kJ/mol）.展开更多
Efficiently and thoroughly degrading organic dyes in wastewater is of great importance and challenge.Herein,vertically oriented mesoporous a-Fe_(2)O_(3)nanorods array(a-Fe_(2)O_(3)-NA)is directly grown on fluorine-dop...Efficiently and thoroughly degrading organic dyes in wastewater is of great importance and challenge.Herein,vertically oriented mesoporous a-Fe_(2)O_(3)nanorods array(a-Fe_(2)O_(3)-NA)is directly grown on fluorine-doped tin oxide(FTO)glass and employed as the photoanode for photoelectrocatalytic degradation of methylene blue simulated dye wastewater.The Ovsites on the a-Fe_(2)O_(3)-NA surface are the active sites for methylene blue(MB)adsorption.Electrons transfer from the adsorbed MB to Fe-O is detected.Compared with electrocatalytic and photocatalytic degradation processes,the photoelectrocatalytic(PEC)process exhibited the best degrading performance and the largest kinetic constant.Hydroxyl,superoxide free radicals,and photo-generated holes play a jointly leading role in the PEC degradation.A possible degrading pathway is suggested by liquid chromatography-mass spectroscopy analysis.This work demonstrates that photoelectrocatalysis by a-Fe_(2)O_(3)-NA has a remarkable superiority over photocatalysis and electrocatalysis in MB degradation.The in-depth investigation of photoelectrocatalytic degradation mechanism in this study is meaningful for organic wastewater treatment.展开更多
基金Supported by National Natural Science Foundation of China
文摘This paper describes the synthesis and free radical ring-opening polymerization of 2-methyl-and 2-methyl-9-n-butyl (-7-methylene-1, 4, 6-trioxaspiro (4, 4) nonane). The structures of the two polymers were verified by IR, 'H and ^(13)C NMR spectra. The substituent on 9-position of 7-methylene-trioxaspiro (4, 4) nonane affects the structure of polymer and polymerization activity. The polymerization mechanism is discussed.
基金Sponsored by the National Science Foundation of China and CAEP(10676003)
文摘The 2,2-dinitropropyl methacrylate（DNPMA） was synthesized by esterification of α-methacrylic acid with 2,2-dinitropropanol.The free-radical bulk polymerization of DNPMA in the presence of 2,2-azobisisobutyronitrile（AIBN） was investigated by differential scanning calorimetry（DSC） in the nonisothermal mode.Kissinger,Ozawa and Barrett methods were applied to determine the activation energy（Ea） and the reaction order of the free-radical polymerization.The results showed that the temperature of exothermic polymerization peaks increased with increasing heating rate.With increasing the molar ratio of monomer/initiator and the heating rate,the reaction order of nonisothermal polymerization was approximately equal to 1.The average Ea value from Kissinger and Ozawa methods（77.74±1.07 kJ/mol） was smaller than the value from the Barrett method（Ea=102.36 kJ/mol）.
基金financially supported by the National Natural Science Foundation of China (22005097)the State Key Laboratory of Physical Chemistry of Solid Surfaces,Xiamen University,Xiamen 361005,P.R.China (201815)。
文摘Efficiently and thoroughly degrading organic dyes in wastewater is of great importance and challenge.Herein,vertically oriented mesoporous a-Fe_(2)O_(3)nanorods array(a-Fe_(2)O_(3)-NA)is directly grown on fluorine-doped tin oxide(FTO)glass and employed as the photoanode for photoelectrocatalytic degradation of methylene blue simulated dye wastewater.The Ovsites on the a-Fe_(2)O_(3)-NA surface are the active sites for methylene blue(MB)adsorption.Electrons transfer from the adsorbed MB to Fe-O is detected.Compared with electrocatalytic and photocatalytic degradation processes,the photoelectrocatalytic(PEC)process exhibited the best degrading performance and the largest kinetic constant.Hydroxyl,superoxide free radicals,and photo-generated holes play a jointly leading role in the PEC degradation.A possible degrading pathway is suggested by liquid chromatography-mass spectroscopy analysis.This work demonstrates that photoelectrocatalysis by a-Fe_(2)O_(3)-NA has a remarkable superiority over photocatalysis and electrocatalysis in MB degradation.The in-depth investigation of photoelectrocatalytic degradation mechanism in this study is meaningful for organic wastewater treatment.
