Chemical functionalization of chitosan biopolymer and chitosan-magnetite nanocomposite was performed with sulfonic acid functional groups to achieve new solid acid materials.The sulfonic acid functional groups were cr...Chemical functionalization of chitosan biopolymer and chitosan-magnetite nanocomposite was performed with sulfonic acid functional groups to achieve new solid acid materials.The sulfonic acid functional groups were created through the ring opening nucleophilic reaction of amine groups of chitosan with 1,4-butane sultone.Fourier transform infrared spectroscopy(FT-IR)and X-ray photoelectron spectroscopies(XPS)verified the successful sulfonic acid functionalization of chitosan.The obtained sulfonic acid functionalized chitosan-magnetite nanocomposite showed superparamagnetic properties according to the vibrating sample magnetometry analysis and exhibited magnetic separation feature from dispersed mixtures.Nitrogen adsorption-desorption analysis indicated the increase in surface area after formation of chitosan-magnetite nanocomposite and functionalization with sulfonic acid.Both of the prepared solid acids exhibited high catalytic activities in the acid-catalyzed acetic acid esterification with n-butanol and benzaldehyde acetalization with ethylene glycol as model reactions.Furthermore,they can be reused several times without considerable loss of their activities.展开更多
The ideal small-diameter vascular grafts should mimic the nanostructure and mechanical properties of nature blood vessel. In this study, electrospun chitosan( CS)/poly( L-lactic-co-ε-caprolactone)( PLCL) nanofibers w...The ideal small-diameter vascular grafts should mimic the nanostructure and mechanical properties of nature blood vessel. In this study, electrospun chitosan( CS)/poly( L-lactic-co-ε-caprolactone)( PLCL) nanofibers were developed for potential small-diameter blood vessel applications. CS is a positively charged polymer which is beneficial for cell attachment and growth,while PLCL provides favorable mechanical support due to its excellent elasticity. Typical nanofibrous structure was observed in both CS/PLCL and pure PLCL scaffolds. The optimal mechanical property could be achieved when the weight ratio of CS/PLCL was 1 ∶ 2.Compared with pure PLCL scaffolds, the CS/PLCL scaffolds showed higher hydrophilicity and markedly promoted the attachment,spreading and proliferation of human umbilical vein endothelial cells( HUVECs). Hence,CS/PLCL scaffolds can be used as potential vascular grafts.展开更多
Sucrose ester( SE) was fixed on surface of poly( ethylene terephthalate)( PET) fibers to improve surface activity. Chitosan( CS) was used to graft onto pretreated PET fibers by sol-gel method. The transformations of s...Sucrose ester( SE) was fixed on surface of poly( ethylene terephthalate)( PET) fibers to improve surface activity. Chitosan( CS) was used to graft onto pretreated PET fibers by sol-gel method. The transformations of surface chemical structure,microcosmic morphology and thermodynamic property were investigated by Fourier transform infrared spectroscopy( FTIR),X-ray photoelectron spectroscopy( XPS), scanning electron microscope( SEM), X-ray diffraction technique( XRD), and thermo gravimetric analysis( TGA),respectively. The wettability and antistatic property of PET fiber were significantly improved after modification by SE and CS.展开更多
Hydrogen with high energy density is an environmental alternative to fossil fuels which can respond to the demand for energy considering environmental conditions.It can be stored on porous materials employing physical...Hydrogen with high energy density is an environmental alternative to fossil fuels which can respond to the demand for energy considering environmental conditions.It can be stored on porous materials employing physical interaction(e.g.adsorption process).The H2storage capacity of materials can be evaluated through electrochemical methods.Therefore,a fast and straightforward approach was employed to fabricate magnesium oxide/chitosan/Au nanoparticles(Mg O/CS/Au)nanocomposites with porous structure for electrochemical hydrogen storage.Herein,laser ablation in water as a fast and green method was utilized to obtain Au nanoparticles(Au NPs).The obtained Au NPs were loaded on Mg O/CS nanocomposite through physical mixing.Structural and morphological investigation of nanocomposites display spherically shaped Au NPs with a diameter of 49–58 nm agglomerated on the Mg O/CS.Drop casting,the fast and cost-effective method was deployed to deposit the benign,and reusable Mg O/CS/Au-x(x is Au NPs weight percentage of 1,3 and 5 wt.%)nanocomposites on stainless steel mesh and their electrochemical hydrogen storage were measured by cyclic voltammetry(CV),indicating good stability and significant hydrogen storage capacity(28 C/g)after 300 CV scans for MgO/CS/Au-1 sample.展开更多
文摘Chemical functionalization of chitosan biopolymer and chitosan-magnetite nanocomposite was performed with sulfonic acid functional groups to achieve new solid acid materials.The sulfonic acid functional groups were created through the ring opening nucleophilic reaction of amine groups of chitosan with 1,4-butane sultone.Fourier transform infrared spectroscopy(FT-IR)and X-ray photoelectron spectroscopies(XPS)verified the successful sulfonic acid functionalization of chitosan.The obtained sulfonic acid functionalized chitosan-magnetite nanocomposite showed superparamagnetic properties according to the vibrating sample magnetometry analysis and exhibited magnetic separation feature from dispersed mixtures.Nitrogen adsorption-desorption analysis indicated the increase in surface area after formation of chitosan-magnetite nanocomposite and functionalization with sulfonic acid.Both of the prepared solid acids exhibited high catalytic activities in the acid-catalyzed acetic acid esterification with n-butanol and benzaldehyde acetalization with ethylene glycol as model reactions.Furthermore,they can be reused several times without considerable loss of their activities.
基金National Natural Science Foundations of China(Nos.31771048,31570984,31271028)International Cooperation Fund of the Science and Technology Commission of Shanghai Municipality,China(No.15540723400)Biomedical Textile Materials Science and Technology(111 Project),China(No.B07024)
文摘The ideal small-diameter vascular grafts should mimic the nanostructure and mechanical properties of nature blood vessel. In this study, electrospun chitosan( CS)/poly( L-lactic-co-ε-caprolactone)( PLCL) nanofibers were developed for potential small-diameter blood vessel applications. CS is a positively charged polymer which is beneficial for cell attachment and growth,while PLCL provides favorable mechanical support due to its excellent elasticity. Typical nanofibrous structure was observed in both CS/PLCL and pure PLCL scaffolds. The optimal mechanical property could be achieved when the weight ratio of CS/PLCL was 1 ∶ 2.Compared with pure PLCL scaffolds, the CS/PLCL scaffolds showed higher hydrophilicity and markedly promoted the attachment,spreading and proliferation of human umbilical vein endothelial cells( HUVECs). Hence,CS/PLCL scaffolds can be used as potential vascular grafts.
文摘Sucrose ester( SE) was fixed on surface of poly( ethylene terephthalate)( PET) fibers to improve surface activity. Chitosan( CS) was used to graft onto pretreated PET fibers by sol-gel method. The transformations of surface chemical structure,microcosmic morphology and thermodynamic property were investigated by Fourier transform infrared spectroscopy( FTIR),X-ray photoelectron spectroscopy( XPS), scanning electron microscope( SEM), X-ray diffraction technique( XRD), and thermo gravimetric analysis( TGA),respectively. The wettability and antistatic property of PET fiber were significantly improved after modification by SE and CS.
文摘Hydrogen with high energy density is an environmental alternative to fossil fuels which can respond to the demand for energy considering environmental conditions.It can be stored on porous materials employing physical interaction(e.g.adsorption process).The H2storage capacity of materials can be evaluated through electrochemical methods.Therefore,a fast and straightforward approach was employed to fabricate magnesium oxide/chitosan/Au nanoparticles(Mg O/CS/Au)nanocomposites with porous structure for electrochemical hydrogen storage.Herein,laser ablation in water as a fast and green method was utilized to obtain Au nanoparticles(Au NPs).The obtained Au NPs were loaded on Mg O/CS nanocomposite through physical mixing.Structural and morphological investigation of nanocomposites display spherically shaped Au NPs with a diameter of 49–58 nm agglomerated on the Mg O/CS.Drop casting,the fast and cost-effective method was deployed to deposit the benign,and reusable Mg O/CS/Au-x(x is Au NPs weight percentage of 1,3 and 5 wt.%)nanocomposites on stainless steel mesh and their electrochemical hydrogen storage were measured by cyclic voltammetry(CV),indicating good stability and significant hydrogen storage capacity(28 C/g)after 300 CV scans for MgO/CS/Au-1 sample.
基金Science&Technology Commission of Shanghai Municipality (No. 20DZ2254900)Municipal Public Welfare Research Project from Jiaxing,Zhejiang Province (No. 2022AY10001)Open Project Program of Jiaxing Key Laboratory of Virus-Related Infectious Diseases.
