The 2,2,6,6-tetramethylpiperidine-1-oxyl(TEMPO)oxidized cellulose film(TOCF)has been attempted to be used as a substrate in electronic and optoelectronic devices,but the changes in the TOCF properties before and after...The 2,2,6,6-tetramethylpiperidine-1-oxyl(TEMPO)oxidized cellulose film(TOCF)has been attempted to be used as a substrate in electronic and optoelectronic devices,but the changes in the TOCF properties before and after annealing treatment have usually been neglected during device fabrication.In this study,TOCF was treated in different atmospheres(air,vacuum,and N2)and at different temperatures,and the properties were investigated.The results indicate that the optical properties are slightly affected by atmosphere and temperature;only slight transmittance loss and haze increase have been observed when TOCF is exposed to an air atmosphere at temperatures of above 120℃.In contrast to the slight effects on the optical properties,cellulose degradation and a loss of film strength have been observed regardless of the atmosphere used when placed at temperatures of above 100℃.Specifically,TOCF was exposed to air,followed by N2 and vacuum atmospheres.Additional Fourier transform infrared(FT-IR)and nuclear magnetic resonance(NMR)results showed that increasing the temperature had no significant effect on the structure of TOCF.Therefore,the annealing temperature should be controlled at a temperature of lower than 100℃and a vacuum atmosphere is preferred.展开更多
In this study,cellulose and xylan were in vitro fermented by pig fecal bacteria.Rapid fermentation(40 h) and extended fermentation(eight weeks)were performed.The properties and ultra-structure changes of post-fermente...In this study,cellulose and xylan were in vitro fermented by pig fecal bacteria.Rapid fermentation(40 h) and extended fermentation(eight weeks)were performed.The properties and ultra-structure changes of post-fermented solid residues were studied.In the end effluent,acetic acid,propionic acid,and butyric acid were observed to be the principal short-chain fatty acids(SCFAs) produced by anaerobic fermentation.Xylan was more accessible to bacteria than cellulose,leading to higher SCFA and lactic acid production.In addition,the crystalline structure of cellulose changed,leading to 16.3% and42.1% increases in crystallinity index for rapid and extended fermentation,respectively.Through this research,a systematic and advanced method to study the degradation chemistry of cellulose and xylan during fermentation was developed.展开更多
A significant amount of lignin and hemicellulose are dissolved in the hydrothermal treatment of biomass.The hemicellulose can be recovered and utilized for value-added products.The dissolved lignin can undergo depolym...A significant amount of lignin and hemicellulose are dissolved in the hydrothermal treatment of biomass.The hemicellulose can be recovered and utilized for value-added products.The dissolved lignin can undergo depolymerization and condensation reactions,and interferes with the separation and purification process for hemicellulose recovery.This paper investigated the behavior of the lignin extracted from the hydrothermal pretreatment of bamboo and its contributions to the physical characteristics of the hydrolysate.It was found that the turbidity of the hydrolysate was strongly associated with the lignin fragments and suspended long chain hemicelluloses.As the lignin depolymerization and condensation reactions occurred simultaneously,the dissolved lignin fractions in the hydrolysate increased first and then decreased.The molecular weight(MW)of the dissolved lignin fragments ranged from 3342~5611 g/mol,with mainly guaiacyl(G)and syringyl(S)unit in the structure.展开更多
基金National Natural Science Foundation of China(31770632)the Innovation Fund from Fujian Agriculture and Forestry University(CXZX2017296 and CXZX2017037).
文摘The 2,2,6,6-tetramethylpiperidine-1-oxyl(TEMPO)oxidized cellulose film(TOCF)has been attempted to be used as a substrate in electronic and optoelectronic devices,but the changes in the TOCF properties before and after annealing treatment have usually been neglected during device fabrication.In this study,TOCF was treated in different atmospheres(air,vacuum,and N2)and at different temperatures,and the properties were investigated.The results indicate that the optical properties are slightly affected by atmosphere and temperature;only slight transmittance loss and haze increase have been observed when TOCF is exposed to an air atmosphere at temperatures of above 120℃.In contrast to the slight effects on the optical properties,cellulose degradation and a loss of film strength have been observed regardless of the atmosphere used when placed at temperatures of above 100℃.Specifically,TOCF was exposed to air,followed by N2 and vacuum atmospheres.Additional Fourier transform infrared(FT-IR)and nuclear magnetic resonance(NMR)results showed that increasing the temperature had no significant effect on the structure of TOCF.Therefore,the annealing temperature should be controlled at a temperature of lower than 100℃and a vacuum atmosphere is preferred.
基金financial support provided by the National Natural Science Foundation of China(No.31270638)
文摘In this study,cellulose and xylan were in vitro fermented by pig fecal bacteria.Rapid fermentation(40 h) and extended fermentation(eight weeks)were performed.The properties and ultra-structure changes of post-fermented solid residues were studied.In the end effluent,acetic acid,propionic acid,and butyric acid were observed to be the principal short-chain fatty acids(SCFAs) produced by anaerobic fermentation.Xylan was more accessible to bacteria than cellulose,leading to higher SCFA and lactic acid production.In addition,the crystalline structure of cellulose changed,leading to 16.3% and42.1% increases in crystallinity index for rapid and extended fermentation,respectively.Through this research,a systematic and advanced method to study the degradation chemistry of cellulose and xylan during fermentation was developed.
基金support from National Natural Science Foundation of China (Grant No.31500488 and 31270638)Natural Science Foundation of Fujian Province (Grant No.2016H6004 and 2016J01089).
文摘A significant amount of lignin and hemicellulose are dissolved in the hydrothermal treatment of biomass.The hemicellulose can be recovered and utilized for value-added products.The dissolved lignin can undergo depolymerization and condensation reactions,and interferes with the separation and purification process for hemicellulose recovery.This paper investigated the behavior of the lignin extracted from the hydrothermal pretreatment of bamboo and its contributions to the physical characteristics of the hydrolysate.It was found that the turbidity of the hydrolysate was strongly associated with the lignin fragments and suspended long chain hemicelluloses.As the lignin depolymerization and condensation reactions occurred simultaneously,the dissolved lignin fractions in the hydrolysate increased first and then decreased.The molecular weight(MW)of the dissolved lignin fragments ranged from 3342~5611 g/mol,with mainly guaiacyl(G)and syringyl(S)unit in the structure.
