In this study,Mg O was partially used as an alkali source in the peroxide bleaching process of bleached chemi-thermomechanical pulp(BCTMP).The effects of substitution percentage of Mg O for Na OH on the bulk,optical,a...In this study,Mg O was partially used as an alkali source in the peroxide bleaching process of bleached chemi-thermomechanical pulp(BCTMP).The effects of substitution percentage of Mg O for Na OH on the bulk,optical,and physical properties of bleached pulp,and the main effluent characteristics were analyzed.In addition,the influencing mechanism of Mgbased alkali on the strength properties of the BCTMP was further investigated.Strength properties of the BCTMPs were investigated as a function of charge characteristics,fiber morphology,surface lignin content,relative bonding area,and hydrogen bonds of the BCTMP.The results showed that cationic demand(CD) and chemical oxygen demand(COD_(Cr)) of the bleaching effluent decreased as the substitution percentage of Mg O for Na OH increased; meanwhile,the bulk and optical properties of the BCTMP increased.Nevertheless,the strength properties(tensile,tear,and burst indices) of the bleached pulp decreased as the substitution percentage of Mg O for Na OH increased.The decrease in the fiber charge density and increase in the surface lignin content affected the fiber swelling,resulting in a decline in pulp interfibers bonding strength and further loss of the tensile and burst indices.展开更多
Generally,hydrogen bonds are formed between cellulose nanocrystals(CNCs)during their water removal and drying,leading to the irreversible aggregation of CNCs,and thus a poor water-redispersibility.The present study de...Generally,hydrogen bonds are formed between cellulose nanocrystals(CNCs)during their water removal and drying,leading to the irreversible aggregation of CNCs,and thus a poor water-redispersibility.The present study demonstrated a novel approach that involved using hydrolyzed sugars generated from the corresponding CNC production as redispersing agents to enhance the redispersibility of CNCs.Experimental data indicated that hydrolyzed sugars can be adsorbed onto CNCs through ethanol precipitation.The oven-dried CNCs onto which hydrolyzed sugars were adsorbed via ethanol precipitation were homogeneously redispersed in water.The redispersed CNCs showed the particle size distribution,Zeta potential,and thermal decomposition properties similar to those of the CNCs without drying.This method may improve the use of hydrolyzed sugars obtained in the hydrolysate from the corresponding CNC production,as well as facilitate the transportation and storage of CNCs.展开更多
Lignin serves as a promising Ultraviolet(UV)absorber within sunscreen industry.However,the commercial development of lignin-containing sunscreens faces challenges due to their low sun protection factor(SPF)and dark co...Lignin serves as a promising Ultraviolet(UV)absorber within sunscreen industry.However,the commercial development of lignin-containing sunscreens faces challenges due to their low sun protection factor(SPF)and dark color in cosmetics industry.In this study,dual modifications on the chemical and physical structures of lignin were conducted to address these challenges.Initially,methylene bis-benzotriazolyl tetramethylbutylphenol(MBBT)was grafted onto alkali lignin(AL)through an atom transfer radical polymerization reaction,resulting in a polymer of AL-graft-MBBT_(3)(AL-g-MBBT_(3)).The sunscreen prepared with 10%AL-g-MBBT_(3) displays outstand-ing sun protection performance with a SPF of 42.93 and a light color with a color difference value(ΔE)of 45.6,in contrast to 10%AL with a SPF of 4.74 and aΔE value of 49.5.Subsequently,AL-g-MBBT_(3) was transformed into normal submicron spheres(AL-g-MBBT_(3) N)and TiO_(2)-loading submicron spheres(AL-g-MBBT_(3)/TiO_(2)).The sun protection performances of 10%AL-g-MBBT_(3) N@C and AL-g-MBBT_(3)/TiO_(2)@C sunscreens obviously surpass that of AL-g-MBBT_(3)@C sunscreen,achieving SPFs of 60.38 and 66.20,respectively.Additionally,there is a considerable improve-ment in the color of these sunscreens,withΔE values of 41.8 and 36.3,respectively.These results provide valuable insights into exploring lignin’s high-value applications in sunscreen.展开更多
Mineral fillers are important for conserving raw fiber materials and reducing production costs in the paper industry.However,the increase in filler content will inevitably result in strength reduction,which limits the...Mineral fillers are important for conserving raw fiber materials and reducing production costs in the paper industry.However,the increase in filler content will inevitably result in strength reduction,which limits the adding amount of filler in paper production.In this study,we designed a cellulose fiber/filler co-refining approach to improve the strength and optical properties of paper;moreover,the synergistic interaction between fibers and precipitated calcium carbonate(PCC)fillers in the co-refining process was investigated.Results of fiber separation and PCC particle size analysis showed that,compared with conventional refining,the content of fines increased,whereas the PCC particle size decreased.More importantly,composites were formed between the PCC and fines,which promoted strength improvement of paper.Physical tests show that the tensile index of paper with 15%PCC content increased by 22%compared with that of the paper filled by conventional method,whereas the brightness and opacity of paper improved by fiber/filler co-refining for a specified filler content.These findings provide a basis for the further development of co-refining filling technology.展开更多
Maintaining a constant chemical concentration(Iso-concentration,IC)has been found to be an effective method to improve peroxide bleaching efficiency for chemi-thermomechanical pulp(CTMP).In this study,the mechanism of...Maintaining a constant chemical concentration(Iso-concentration,IC)has been found to be an effective method to improve peroxide bleaching efficiency for chemi-thermomechanical pulp(CTMP).In this study,the mechanism of IC bleaching was investigated.The concentrations of H2O2 and total alkali in IC bleaching were monitored and compared with those in conventional bleaching processes.Control experiments without pulp were carried out to explore the effects of bleaching additives on H2O2 decomposition.The results showed that the concentrations of H2O2 and the total alkali at the early and later stages of IC bleaching were relatively low and high,respectively;thus,undesired decomposition of H2O2 was inhibited,and brightness was improved.Moreover,the stabilizer played an important role in inhibiting the undesired H2O2 decomposition.This may explain why high bleaching efficiency was achieved in IC bleaching.These findings would provide valuable insight for the production of high-brightness bleached chemi-thermomechanical pulp(BCTMP).展开更多
Depolymerization of lignin is an important step to obtain lignin monomer for the synthesis of functional bio-polymers.In this paper,catalytic degradation/depolymerization of an alkali lignin was investigated in a supe...Depolymerization of lignin is an important step to obtain lignin monomer for the synthesis of functional bio-polymers.In this paper,catalytic degradation/depolymerization of an alkali lignin was investigated in a supercritical ethanol system.The process conditions were optimized in terms of lignin monomer yield,and the liquid products and solid residue were characterized.Results show that the conversion rate of the alkali lignin was improved in both the Ni7Au3 catalyzed and Nickel-catalyzed systems with supercritical ethanol as the solvent.The maximum lignin conversion rate was 69.57%and 68%respectively for the Ni7Au3 and Nickel-based catalysis systems.Gas chromatography/mass spectroscopy(GC/MS)analysis indicated that the catalytic depolymerization products of alkali lignin were mainly monomeric phenolic compounds such as 2-methoxyphenol.The highest yield of 2-methoxyphenol(84.72%)was achieved with Ni7Au3 as the catalyst.展开更多
With the rapid development of“Internet of Things”and human-computer interaction techniques,it is essential and urgent to develop facile and scalable fabrication platforms for stretchable flexible sensor.Herein,we re...With the rapid development of“Internet of Things”and human-computer interaction techniques,it is essential and urgent to develop facile and scalable fabrication platforms for stretchable flexible sensor.Herein,we report a facile strategy of using the green choline chloride-acrylamide deep eutectic solvent(CC-AM DES)to guide the in-situ ring-opening polymerization ofα-lipoic acid(LA),leading to the successful development of a stretchable ionogel material.The as-prepared ionogel from CC-AM DES system exhibits multifunctional merits including the super stretchability(>9000%),100%UV-blocking ability,tunable adhesiveness(29-414 kPa),high ionic conductivity(4.45×10^(-4) S/cm),and ideal anti-freezing(-27℃).In addition,this outstanding ionogel can be readily coated on various material substrates with designable shapes and patterns.Owning to these promising properties and performances,a scalable flexible strain sensor is assembled from the ionogel and exhibits stable resistance variations(R/R_(0))towards multiple external mechanical stimulus.This study provides a green,cost effective,and scalable strategy to fabricate ionogel materials and multifunctional flexible strain sensors,showing a great potential in the fast-emerging highly stretchable wearable/flexible electronics.展开更多
Lignocellulosic biomass such as plants and agricultural waste are ideal to tackle the current energy crisis and energy-related environmental issues.Carbon-rich lignin is abundant in lignocellulosic biomass,whose high-...Lignocellulosic biomass such as plants and agricultural waste are ideal to tackle the current energy crisis and energy-related environmental issues.Carbon-rich lignin is abundant in lignocellulosic biomass,whose high-value transformation and utilization has been the most urgent problem to be solved.Herein,we propose a method for the preparation of porous carbon from lignin employing an H_(3)PO_(4)-assisted hydrothermal method.We characterize the as-prepared lignin-derived porous carbon and investigate its potential for energy storage.After assisted hydrothermal treatment followed by carbonization at 800℃,the lignin-derived porous carbon displays a high specific capacitance(223.6 F·g^(–1) at 0.1 A·g^(–1))and excellent cycling ability with good capacitance retention.In this present study,the resultant lignin-derived porous carbon was used as the electrode of a supercapacitor,illustrating yet another potential high-value use for lignin,namely as a candidate for the sustainable fabrication of main supercapacitor components.展开更多
基金financially supported by the Natural Science Foundation of China (31070528)Project of China “Twelfth Five-Year” National Science and Technology Supporting Plan (2011BAC11B04)the Foundation of State Key Laboratory of Pulp and Paper Engineering
文摘In this study,Mg O was partially used as an alkali source in the peroxide bleaching process of bleached chemi-thermomechanical pulp(BCTMP).The effects of substitution percentage of Mg O for Na OH on the bulk,optical,and physical properties of bleached pulp,and the main effluent characteristics were analyzed.In addition,the influencing mechanism of Mgbased alkali on the strength properties of the BCTMP was further investigated.Strength properties of the BCTMPs were investigated as a function of charge characteristics,fiber morphology,surface lignin content,relative bonding area,and hydrogen bonds of the BCTMP.The results showed that cationic demand(CD) and chemical oxygen demand(COD_(Cr)) of the bleaching effluent decreased as the substitution percentage of Mg O for Na OH increased; meanwhile,the bulk and optical properties of the BCTMP increased.Nevertheless,the strength properties(tensile,tear,and burst indices) of the bleached pulp decreased as the substitution percentage of Mg O for Na OH increased.The decrease in the fiber charge density and increase in the surface lignin content affected the fiber swelling,resulting in a decline in pulp interfibers bonding strength and further loss of the tensile and burst indices.
基金This work was supported by the Foundation(No.202105)of Tianjin Key Laboratory of Pulp&Paper(Tianjin University of Science&Technology)the Shaanxi University of Science and Technology Academic Leader Training Program(2013XSD25).
文摘Generally,hydrogen bonds are formed between cellulose nanocrystals(CNCs)during their water removal and drying,leading to the irreversible aggregation of CNCs,and thus a poor water-redispersibility.The present study demonstrated a novel approach that involved using hydrolyzed sugars generated from the corresponding CNC production as redispersing agents to enhance the redispersibility of CNCs.Experimental data indicated that hydrolyzed sugars can be adsorbed onto CNCs through ethanol precipitation.The oven-dried CNCs onto which hydrolyzed sugars were adsorbed via ethanol precipitation were homogeneously redispersed in water.The redispersed CNCs showed the particle size distribution,Zeta potential,and thermal decomposition properties similar to those of the CNCs without drying.This method may improve the use of hydrolyzed sugars obtained in the hydrolysate from the corresponding CNC production,as well as facilitate the transportation and storage of CNCs.
基金support for this work by Natural Science Foundation of Guangxi Province,China(No.2021GXNSFDA196006)National Natural Science Foundation of China(No.22268007+1 种基金No.21766002)Guangxi Innovation Driven Development Special Fund Project,China(No.AA17204092).
文摘Lignin serves as a promising Ultraviolet(UV)absorber within sunscreen industry.However,the commercial development of lignin-containing sunscreens faces challenges due to their low sun protection factor(SPF)and dark color in cosmetics industry.In this study,dual modifications on the chemical and physical structures of lignin were conducted to address these challenges.Initially,methylene bis-benzotriazolyl tetramethylbutylphenol(MBBT)was grafted onto alkali lignin(AL)through an atom transfer radical polymerization reaction,resulting in a polymer of AL-graft-MBBT_(3)(AL-g-MBBT_(3)).The sunscreen prepared with 10%AL-g-MBBT_(3) displays outstand-ing sun protection performance with a SPF of 42.93 and a light color with a color difference value(ΔE)of 45.6,in contrast to 10%AL with a SPF of 4.74 and aΔE value of 49.5.Subsequently,AL-g-MBBT_(3) was transformed into normal submicron spheres(AL-g-MBBT_(3) N)and TiO_(2)-loading submicron spheres(AL-g-MBBT_(3)/TiO_(2)).The sun protection performances of 10%AL-g-MBBT_(3) N@C and AL-g-MBBT_(3)/TiO_(2)@C sunscreens obviously surpass that of AL-g-MBBT_(3)@C sunscreen,achieving SPFs of 60.38 and 66.20,respectively.Additionally,there is a considerable improve-ment in the color of these sunscreens,withΔE values of 41.8 and 36.3,respectively.These results provide valuable insights into exploring lignin’s high-value applications in sunscreen.
基金This work was financially supported by Innovation Capability Support Program of Shaanxi(2020KJXX082)the Foundation(202005)of Tianjin Key Laboratory of Pulp&Paper(Tianjin University of Science&Technology).
文摘Mineral fillers are important for conserving raw fiber materials and reducing production costs in the paper industry.However,the increase in filler content will inevitably result in strength reduction,which limits the adding amount of filler in paper production.In this study,we designed a cellulose fiber/filler co-refining approach to improve the strength and optical properties of paper;moreover,the synergistic interaction between fibers and precipitated calcium carbonate(PCC)fillers in the co-refining process was investigated.Results of fiber separation and PCC particle size analysis showed that,compared with conventional refining,the content of fines increased,whereas the PCC particle size decreased.More importantly,composites were formed between the PCC and fines,which promoted strength improvement of paper.Physical tests show that the tensile index of paper with 15%PCC content increased by 22%compared with that of the paper filled by conventional method,whereas the brightness and opacity of paper improved by fiber/filler co-refining for a specified filler content.These findings provide a basis for the further development of co-refining filling technology.
文摘Maintaining a constant chemical concentration(Iso-concentration,IC)has been found to be an effective method to improve peroxide bleaching efficiency for chemi-thermomechanical pulp(CTMP).In this study,the mechanism of IC bleaching was investigated.The concentrations of H2O2 and total alkali in IC bleaching were monitored and compared with those in conventional bleaching processes.Control experiments without pulp were carried out to explore the effects of bleaching additives on H2O2 decomposition.The results showed that the concentrations of H2O2 and the total alkali at the early and later stages of IC bleaching were relatively low and high,respectively;thus,undesired decomposition of H2O2 was inhibited,and brightness was improved.Moreover,the stabilizer played an important role in inhibiting the undesired H2O2 decomposition.This may explain why high bleaching efficiency was achieved in IC bleaching.These findings would provide valuable insight for the production of high-brightness bleached chemi-thermomechanical pulp(BCTMP).
基金supported by the National Key Research and Development Program of China(Grant 2016YFE0125800)the National Natural Science Foundation of China(Grant 31500492)+4 种基金China Postdoctoral Science Foundation(Grant 2017M612035)Zhejiang Provincial Natural Science Foundation of China(Grant LY16C160005)the Foundation(Grant 201601)of Tianjin Key Laboratory of Pulp&Paper(Tianjin University of Science&Technology)the open fund of State Key Laboratory of Pulp and Paper Engineering(Grant No.201605)the Science Foundation of Zhejiang Sci-Tech University(Grant No.14012079-Y).
文摘Depolymerization of lignin is an important step to obtain lignin monomer for the synthesis of functional bio-polymers.In this paper,catalytic degradation/depolymerization of an alkali lignin was investigated in a supercritical ethanol system.The process conditions were optimized in terms of lignin monomer yield,and the liquid products and solid residue were characterized.Results show that the conversion rate of the alkali lignin was improved in both the Ni7Au3 catalyzed and Nickel-catalyzed systems with supercritical ethanol as the solvent.The maximum lignin conversion rate was 69.57%and 68%respectively for the Ni7Au3 and Nickel-based catalysis systems.Gas chromatography/mass spectroscopy(GC/MS)analysis indicated that the catalytic depolymerization products of alkali lignin were mainly monomeric phenolic compounds such as 2-methoxyphenol.The highest yield of 2-methoxyphenol(84.72%)was achieved with Ni7Au3 as the catalyst.
基金supported by the National Natural Science Foundation of China(32071715)Canada Research Chairs program of the Government of Canada,and National Science Foundation for Post-doctoral Scientists of China(2019M651050).
文摘With the rapid development of“Internet of Things”and human-computer interaction techniques,it is essential and urgent to develop facile and scalable fabrication platforms for stretchable flexible sensor.Herein,we report a facile strategy of using the green choline chloride-acrylamide deep eutectic solvent(CC-AM DES)to guide the in-situ ring-opening polymerization ofα-lipoic acid(LA),leading to the successful development of a stretchable ionogel material.The as-prepared ionogel from CC-AM DES system exhibits multifunctional merits including the super stretchability(>9000%),100%UV-blocking ability,tunable adhesiveness(29-414 kPa),high ionic conductivity(4.45×10^(-4) S/cm),and ideal anti-freezing(-27℃).In addition,this outstanding ionogel can be readily coated on various material substrates with designable shapes and patterns.Owning to these promising properties and performances,a scalable flexible strain sensor is assembled from the ionogel and exhibits stable resistance variations(R/R_(0))towards multiple external mechanical stimulus.This study provides a green,cost effective,and scalable strategy to fabricate ionogel materials and multifunctional flexible strain sensors,showing a great potential in the fast-emerging highly stretchable wearable/flexible electronics.
基金The authors wish to express their gratitude for the financial support from the National Science Foundation for Post-doctoral Scientists of China(Grant No.2019M651050)Guangxi Key Laboratory of Clean Pulp&Papermaking and Pollution Control,College of Light Industry and Food Engineering,Guangxi University(Grant No.2019KF32).
文摘Lignocellulosic biomass such as plants and agricultural waste are ideal to tackle the current energy crisis and energy-related environmental issues.Carbon-rich lignin is abundant in lignocellulosic biomass,whose high-value transformation and utilization has been the most urgent problem to be solved.Herein,we propose a method for the preparation of porous carbon from lignin employing an H_(3)PO_(4)-assisted hydrothermal method.We characterize the as-prepared lignin-derived porous carbon and investigate its potential for energy storage.After assisted hydrothermal treatment followed by carbonization at 800℃,the lignin-derived porous carbon displays a high specific capacitance(223.6 F·g^(–1) at 0.1 A·g^(–1))and excellent cycling ability with good capacitance retention.In this present study,the resultant lignin-derived porous carbon was used as the electrode of a supercapacitor,illustrating yet another potential high-value use for lignin,namely as a candidate for the sustainable fabrication of main supercapacitor components.
