Organomontmorillonites （organo-MMT） were synthesized by means of montmorillonites （MMT） modified with a series of 2-methacryloyloxy ethyl alkyl dimethyl ammonium bromide （MAAB） having different alkyl chain lengt...Organomontmorillonites （organo-MMT） were synthesized by means of montmorillonites （MMT） modified with a series of 2-methacryloyloxy ethyl alkyl dimethyl ammonium bromide （MAAB） having different alkyl chain lengths as cationic surfactants through a cationic exchanging reaction, and were characterized by FTIR, TG, elemental analysis, and XRD. The microenvironment of the organic interlayer such as the orientation and arrangement of the alkyl chains of MAAB, as well as the properties of nanocomposite hydrogels, were also investigated. The amount of organic components absorbed on interlayer and the basal spacing of organo-MMT both increase with the increasing of alkyl length of MAAB. When carbon number of alkyl chain is in the region of 8 to 14, the alkyl chains between layers would adopt a disordered gauche conformation; while the carbon number is 16, an ordered all-trans conformation with a vertical orientation would be found together with the disordered gauche conformation according to the results of XRD and FTIR. Due to the difference of microenvironment of organic interlayer, the Young＇s moduli of the nanocomposite hydrogels increased as the alkyl chains of MAAB became longer.展开更多
The synthesis, characterization and thermal decomposition mechanism of cetyltrimethyl ammonium tetrathiotungstate （CTriMATT） were studied herein. The as-synthesized CTriMATT was characterized by Elemental analysis, ...The synthesis, characterization and thermal decomposition mechanism of cetyltrimethyl ammonium tetrathiotungstate （CTriMATT） were studied herein. The as-synthesized CTriMATT was characterized by Elemental analysis, X-ray diffraction （XRD）, Fourier transform infrared （FT-IR）, Ultraviolet visible （UV-Vis） spectra. The results showed that the as-synthesized CTriMATT had high purity and good crystallinity. The introduction of alkyl groups induced a shift of the stretching vibration band of W-S bond to lower wavenumber, while it had no influence on the position of WS4^2-. Thermogravimetric analysis （TG）, differential thermal analysis （DTA） and in situ XRD characterizations revealed that CTriMATT began to decompose at 423 K in nitrogen and was converted to WS2 eventually. In addition, the decomposition product of CTriMATT at 673 K in nitrogen was characterized by N2 adsorption （BET） and scanning electron microscopy （SEM）. The results demonstrated that WS2 with higher specific surface area, and pore volume could be obtained from the thermal decomposition of CTriMATT in nitrogen.展开更多
先用甲醛-甲酸法(eschweiler-clarke反应)合成N,N-二甲基壳聚糖(DMC),再与溴代烷进行Hoffman烷基化反应制备了N-十二烷基-N,N-二甲基壳聚糖季铵盐(DODMC)和N-十六烷基-N,N-二甲基壳聚糖季铵盐(HDMC),用FT-IR、1 H NMR、EA、TG等对产物...先用甲醛-甲酸法(eschweiler-clarke反应)合成N,N-二甲基壳聚糖(DMC),再与溴代烷进行Hoffman烷基化反应制备了N-十二烷基-N,N-二甲基壳聚糖季铵盐(DODMC)和N-十六烷基-N,N-二甲基壳聚糖季铵盐(HDMC),用FT-IR、1 H NMR、EA、TG等对产物进行表征。抗菌实验结果表明所合成产物具有较好的抗菌活性,对革兰氏阳性菌S.aureus的抗菌活性优于革兰氏阴性菌E.coli,抗菌活性随着烷基链长度的增加而增强;产物在pH值=5.5比在pH值=7.2条件下表现出更好的抗菌活性;在碱性及中性条件下,HDMC的抗菌活性随着季铵化度的提高而提高,而在酸性条件下抗菌活性则随着季铵化度提高而降低。展开更多
文摘Organomontmorillonites （organo-MMT） were synthesized by means of montmorillonites （MMT） modified with a series of 2-methacryloyloxy ethyl alkyl dimethyl ammonium bromide （MAAB） having different alkyl chain lengths as cationic surfactants through a cationic exchanging reaction, and were characterized by FTIR, TG, elemental analysis, and XRD. The microenvironment of the organic interlayer such as the orientation and arrangement of the alkyl chains of MAAB, as well as the properties of nanocomposite hydrogels, were also investigated. The amount of organic components absorbed on interlayer and the basal spacing of organo-MMT both increase with the increasing of alkyl length of MAAB. When carbon number of alkyl chain is in the region of 8 to 14, the alkyl chains between layers would adopt a disordered gauche conformation; while the carbon number is 16, an ordered all-trans conformation with a vertical orientation would be found together with the disordered gauche conformation according to the results of XRD and FTIR. Due to the difference of microenvironment of organic interlayer, the Young＇s moduli of the nanocomposite hydrogels increased as the alkyl chains of MAAB became longer.
基金This work is sponsored by National Key Fundamental Research Development Plan ("973" Plan, No.2004CB217807)the China National Petroleum Corporation (No. B04A50502)
文摘The synthesis, characterization and thermal decomposition mechanism of cetyltrimethyl ammonium tetrathiotungstate （CTriMATT） were studied herein. The as-synthesized CTriMATT was characterized by Elemental analysis, X-ray diffraction （XRD）, Fourier transform infrared （FT-IR）, Ultraviolet visible （UV-Vis） spectra. The results showed that the as-synthesized CTriMATT had high purity and good crystallinity. The introduction of alkyl groups induced a shift of the stretching vibration band of W-S bond to lower wavenumber, while it had no influence on the position of WS4^2-. Thermogravimetric analysis （TG）, differential thermal analysis （DTA） and in situ XRD characterizations revealed that CTriMATT began to decompose at 423 K in nitrogen and was converted to WS2 eventually. In addition, the decomposition product of CTriMATT at 673 K in nitrogen was characterized by N2 adsorption （BET） and scanning electron microscopy （SEM）. The results demonstrated that WS2 with higher specific surface area, and pore volume could be obtained from the thermal decomposition of CTriMATT in nitrogen.
文摘先用甲醛-甲酸法(eschweiler-clarke反应)合成N,N-二甲基壳聚糖(DMC),再与溴代烷进行Hoffman烷基化反应制备了N-十二烷基-N,N-二甲基壳聚糖季铵盐(DODMC)和N-十六烷基-N,N-二甲基壳聚糖季铵盐(HDMC),用FT-IR、1 H NMR、EA、TG等对产物进行表征。抗菌实验结果表明所合成产物具有较好的抗菌活性,对革兰氏阳性菌S.aureus的抗菌活性优于革兰氏阴性菌E.coli,抗菌活性随着烷基链长度的增加而增强;产物在pH值=5.5比在pH值=7.2条件下表现出更好的抗菌活性;在碱性及中性条件下,HDMC的抗菌活性随着季铵化度的提高而提高,而在酸性条件下抗菌活性则随着季铵化度提高而降低。
