A novel fluorene-based conjugated copolymer containing cyclobutenedione unit was synthesized by Suzuki reaction. Its structure and properties were characterized by FTIR, 1HNMR, elemental analysis, PL spectroscopy, DSC...A novel fluorene-based conjugated copolymer containing cyclobutenedione unit was synthesized by Suzuki reaction. Its structure and properties were characterized by FTIR, 1HNMR, elemental analysis, PL spectroscopy, DSC, TGA and cyclic voltammetry. The resulting polymer shows strong yellow PL emission (561 nm) and good solubility in polar aprotic solvents, i.e. THF, DMF, DMAC, DMSO, etc. DSC and TGA studies reveal that the novel polymer possesses excellent thermal stability with high glass transition temperature of 127℃ and onset decomposition temperature of 411℃. Cyclic voltammetry measurement demonstrated that the polymer has both hole and electron-transporting property.展开更多
Efficacious regulation of the geometric and electronic structures of carbon nanomaterials via the introduction of defects and their synergy is essential to achieving good electrochemical performance.However,the guidel...Efficacious regulation of the geometric and electronic structures of carbon nanomaterials via the introduction of defects and their synergy is essential to achieving good electrochemical performance.However,the guidelines for designing hybrid materials with advantageous structures and the fundamental understanding of their electrocatalytic mechanisms remain unclear.Herein,superfine Pt and PtCu nanoparticles supported by novel S,N‐co‐doped multi‐walled CNT(MWCNTs)were prepared through the innovative pyrolysis of a poly(3,4‐ethylenedioxythiophene)/polyaniline copolymer as a source of S and N.The uniform wrapping of the copolymer around the MWCNTs provides a high density of evenly distributed defects on the surface after the pyrolysis treatment,facilitating the uniform distribution of ultrafine Pt and PtCu nanoparticles.Remarkably,the Pt_(1)Cu_(2)/SN‐MWCNTs show an obviously larger electroactive surface area and higher mass activity,stability,and CO poisoning resistance in methanol oxidation compared to Pt/SN‐MWCNTs,Pt/S‐MWCNTs,Pt/N‐MWCNTs,and commercial Pt/C.Density functional theory studies confirm that the co‐doping of S and N considerably deforms the CNTs and polarizes the adjacent C atoms.Consequently,both the adsorption of Pt1Cu2 onto the SN‐MWCNTs and the subsequent adsorption of methanol are enhanced;in addition,the catalytic activity of Pt_(1)Cu_(2)/SN‐MWCNTs for methanol oxidation is thermodynamically and kinetically more favorable than that of its CNT and N‐CNT counterparts.This work provides a novel method to fabricate high‐performance fuel cell electrocatalysts with highly dispersed and stable Pt‐based nanoparticles on a carbon substrate.展开更多
L-lactic acid (L-LA) based copolymer/hydroxylation vermiculites composites (PLLA-co-bis A/HVMTs) were prepared by in situ reaction among L-LA, adipic acid, and hydroxylation lamellar vermiculites (HVMTs) using bisphen...L-lactic acid (L-LA) based copolymer/hydroxylation vermiculites composites (PLLA-co-bis A/HVMTs) were prepared by in situ reaction among L-LA, adipic acid, and hydroxylation lamellar vermiculites (HVMTs) using bisphenol-A epoxy resin as chain extending agent. HVMTs were obtained by sulfuric acid-leaching of lamellar vermiculites (VMTs). The effects of sulfuric acid leaching on the VMTs structure were characterized by X-ray diffraction (XRD), 29Si magic-angle spinning nuclear magnetic resonance(29Si NMR), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), and thermogravimetric analysis (TGA). FTIR, FE-SEM, and TGA were used to characterize the reaction activity of HVMTs. The results indicated that VMTs with increased hydroxyl groups had been successfully obtained and could react with -COOH of the reaction system. The amount of L-LA based copolymer grafted on the surface of HVMTs was more than 22%. The onset decomposition temperature of L-LA based copolymer grafted on the surface of HVMTs was 30℃ higher than that of free L-LA based copolymer.展开更多
PVP, a synthetic polymer and chitosan, a natural polymer are biocompatible and have presented a great variety of interesting properties for cosmetic, biomedical, pharmaceutical and biotechnological applications, Many ...PVP, a synthetic polymer and chitosan, a natural polymer are biocompatible and have presented a great variety of interesting properties for cosmetic, biomedical, pharmaceutical and biotechnological applications, Many alternatives to improve the polymer propeties has been made as bleeding polymers, for example. In this work, two different techniques of hydrogel attainment were used: one from mixtures of acid aqueous cosolutions of chitosan and PVP, whose resultant films and solutions were irradiated, afterwards, by ultraviolet radiation (λ = 254 nm), another one from the reaction of poly (N-vinyl-2-pyrrolidone-co-acrolein)-a novel copolymer synthesized in our biomaterials laboratory-and chitosan. In the first one alternatives it was possible produce hydrogels directly from mixtures of aqueous acidic co-solutions of both polymers. In the second one, the attainment of hydrogels from Schiff base has proved to be an effective methodology for the production of hydrogels, showing good values of gel content and swelling.展开更多
A smart polycarbonate（PCA） copolymer-based nanoparticle（NanoPCA） with pH-responsive, long-term stability, and tumor targeting ability was successfully developed by synthesizing and assembling a series of functiona...A smart polycarbonate（PCA） copolymer-based nanoparticle（NanoPCA） with pH-responsive, long-term stability, and tumor targeting ability was successfully developed by synthesizing and assembling a series of functional PCA-based copolymers including poly（2-amino-l,3-propanediol carbonate-co-L-lactide）[P（CA-co-LA）], poly（2- amino-1,3-propanediol carbonate-co-L-lactide）-g-methoxy-poly（ethylene glycol）[P（CA-co-LA）-g-MPEG], and poly（2-amino-1,3-propanediol carbonate-co-L-lactide）-g-poly（ethylene glycol）-cyclic（Arg-Gly-Asp-D-Phe-Lys） [P（CA-co-LA）-g-PEG-cRGD] for targeted anticancer drug delivery, pH-Responsive studies demonstrated that the loading doxorubicin（DOX） released faster from NanoPCA at acidic conditions due to protonation effects of P（CA-co-LA） copolymers. Furthermore, the in vitro and in vivo investigations demonstrate that the DOX-loaded NanoPCA exhibited significant tumor targeting ability, outstanding antitumor effect and excellent biological safety in the treatment of oral squamous cell carcinoma（OSCC）. Therefore, this work provides a promising drug delivery plat-form for cancer therapy and other applications.展开更多
The model waste water of cationic youhaocry1 yellow X-8GL dye was treated with the copolymer of lignosulfonate calcium and acrylamide.The optimization tests were conducted regarding the four effect factors,e.g.,the ra...The model waste water of cationic youhaocry1 yellow X-8GL dye was treated with the copolymer of lignosulfonate calcium and acrylamide.The optimization tests were conducted regarding the four effect factors,e.g.,the rate between lignosulfonate calcium and acrylamide,the amount of flocculating agent,PHvalue and the initial concentration of the dye.It was concluded that the enhancement of rate between lignosulfonate calcium and acrylamide can not only reduce the cost but also improve the decolourization rate. As a decolouring agent,the copolymer was more suitable for higher initial concentration and neutral condition.85%of decolourization rate could be obtained under suitable dosage.展开更多
文摘A novel fluorene-based conjugated copolymer containing cyclobutenedione unit was synthesized by Suzuki reaction. Its structure and properties were characterized by FTIR, 1HNMR, elemental analysis, PL spectroscopy, DSC, TGA and cyclic voltammetry. The resulting polymer shows strong yellow PL emission (561 nm) and good solubility in polar aprotic solvents, i.e. THF, DMF, DMAC, DMSO, etc. DSC and TGA studies reveal that the novel polymer possesses excellent thermal stability with high glass transition temperature of 127℃ and onset decomposition temperature of 411℃. Cyclic voltammetry measurement demonstrated that the polymer has both hole and electron-transporting property.
文摘Efficacious regulation of the geometric and electronic structures of carbon nanomaterials via the introduction of defects and their synergy is essential to achieving good electrochemical performance.However,the guidelines for designing hybrid materials with advantageous structures and the fundamental understanding of their electrocatalytic mechanisms remain unclear.Herein,superfine Pt and PtCu nanoparticles supported by novel S,N‐co‐doped multi‐walled CNT(MWCNTs)were prepared through the innovative pyrolysis of a poly(3,4‐ethylenedioxythiophene)/polyaniline copolymer as a source of S and N.The uniform wrapping of the copolymer around the MWCNTs provides a high density of evenly distributed defects on the surface after the pyrolysis treatment,facilitating the uniform distribution of ultrafine Pt and PtCu nanoparticles.Remarkably,the Pt_(1)Cu_(2)/SN‐MWCNTs show an obviously larger electroactive surface area and higher mass activity,stability,and CO poisoning resistance in methanol oxidation compared to Pt/SN‐MWCNTs,Pt/S‐MWCNTs,Pt/N‐MWCNTs,and commercial Pt/C.Density functional theory studies confirm that the co‐doping of S and N considerably deforms the CNTs and polarizes the adjacent C atoms.Consequently,both the adsorption of Pt1Cu2 onto the SN‐MWCNTs and the subsequent adsorption of methanol are enhanced;in addition,the catalytic activity of Pt_(1)Cu_(2)/SN‐MWCNTs for methanol oxidation is thermodynamically and kinetically more favorable than that of its CNT and N‐CNT counterparts.This work provides a novel method to fabricate high‐performance fuel cell electrocatalysts with highly dispersed and stable Pt‐based nanoparticles on a carbon substrate.
基金National High-Tech Research and Development Program of China ( 863 Program ) ( No. 2007AA03Z336) Program for New Century Excellent Talents in University,China ( No. NCET-07-0174) +1 种基金National Natural Science Foundations of China ( No. 21074021,No.50673018) The Fundamental Research Funds for the Central Universities ( No. 2011D10543)
文摘L-lactic acid (L-LA) based copolymer/hydroxylation vermiculites composites (PLLA-co-bis A/HVMTs) were prepared by in situ reaction among L-LA, adipic acid, and hydroxylation lamellar vermiculites (HVMTs) using bisphenol-A epoxy resin as chain extending agent. HVMTs were obtained by sulfuric acid-leaching of lamellar vermiculites (VMTs). The effects of sulfuric acid leaching on the VMTs structure were characterized by X-ray diffraction (XRD), 29Si magic-angle spinning nuclear magnetic resonance(29Si NMR), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), and thermogravimetric analysis (TGA). FTIR, FE-SEM, and TGA were used to characterize the reaction activity of HVMTs. The results indicated that VMTs with increased hydroxyl groups had been successfully obtained and could react with -COOH of the reaction system. The amount of L-LA based copolymer grafted on the surface of HVMTs was more than 22%. The onset decomposition temperature of L-LA based copolymer grafted on the surface of HVMTs was 30℃ higher than that of free L-LA based copolymer.
基金the Fundacao de Amparo a Pesquisa do Estado de Sao Paulo e FAPESP and the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico e CNPq,for financial support
文摘PVP, a synthetic polymer and chitosan, a natural polymer are biocompatible and have presented a great variety of interesting properties for cosmetic, biomedical, pharmaceutical and biotechnological applications, Many alternatives to improve the polymer propeties has been made as bleeding polymers, for example. In this work, two different techniques of hydrogel attainment were used: one from mixtures of acid aqueous cosolutions of chitosan and PVP, whose resultant films and solutions were irradiated, afterwards, by ultraviolet radiation (λ = 254 nm), another one from the reaction of poly (N-vinyl-2-pyrrolidone-co-acrolein)-a novel copolymer synthesized in our biomaterials laboratory-and chitosan. In the first one alternatives it was possible produce hydrogels directly from mixtures of aqueous acidic co-solutions of both polymers. In the second one, the attainment of hydrogels from Schiff base has proved to be an effective methodology for the production of hydrogels, showing good values of gel content and swelling.
基金Supported by the National High Technolgy Researeh and Development Program of China（No.2013AA032201）, the National Natural Science Foundation of China（Nos.81703003, 51303009, 21476018, 21622601） and the National Key R＆D Program of China（No.2015CB932101 ）.
文摘A smart polycarbonate（PCA） copolymer-based nanoparticle（NanoPCA） with pH-responsive, long-term stability, and tumor targeting ability was successfully developed by synthesizing and assembling a series of functional PCA-based copolymers including poly（2-amino-l,3-propanediol carbonate-co-L-lactide）[P（CA-co-LA）], poly（2- amino-1,3-propanediol carbonate-co-L-lactide）-g-methoxy-poly（ethylene glycol）[P（CA-co-LA）-g-MPEG], and poly（2-amino-1,3-propanediol carbonate-co-L-lactide）-g-poly（ethylene glycol）-cyclic（Arg-Gly-Asp-D-Phe-Lys） [P（CA-co-LA）-g-PEG-cRGD] for targeted anticancer drug delivery, pH-Responsive studies demonstrated that the loading doxorubicin（DOX） released faster from NanoPCA at acidic conditions due to protonation effects of P（CA-co-LA） copolymers. Furthermore, the in vitro and in vivo investigations demonstrate that the DOX-loaded NanoPCA exhibited significant tumor targeting ability, outstanding antitumor effect and excellent biological safety in the treatment of oral squamous cell carcinoma（OSCC）. Therefore, this work provides a promising drug delivery plat-form for cancer therapy and other applications.
文摘The model waste water of cationic youhaocry1 yellow X-8GL dye was treated with the copolymer of lignosulfonate calcium and acrylamide.The optimization tests were conducted regarding the four effect factors,e.g.,the rate between lignosulfonate calcium and acrylamide,the amount of flocculating agent,PHvalue and the initial concentration of the dye.It was concluded that the enhancement of rate between lignosulfonate calcium and acrylamide can not only reduce the cost but also improve the decolourization rate. As a decolouring agent,the copolymer was more suitable for higher initial concentration and neutral condition.85%of decolourization rate could be obtained under suitable dosage.
