A kind of nanokaolin powder with a thickness of 20-50nm and an average diameter of 300nm is produced through combined procedure of purification, delamination, surface modification and pulverization. The application ex...A kind of nanokaolin powder with a thickness of 20-50nm and an average diameter of 300nm is produced through combined procedure of purification, delamination, surface modification and pulverization. The application experiments in butadiene rubber (BR), ethylene-propylene diene methylene (EPDM), and natural rubber (NR) indicates that this nano-kaolin powder material is much better than precipitated silica in reinforcement, while in styrene-butadiene rubber (SBR) it is close to precipitated silica. Nanokaolin is of superiority in elasticity, elongation at break, anti-flexure property.展开更多
A new coordination polymer,Zn(bpy)L(BUC‐21),(H2L=cis‐1,3‐dibenzyl‐2‐imidazolidone‐4,5‐dicarboxylic acid,bpy=4,4′‐bipyridine),has been synthesized under hydrothermal conditions,and characterized by single‐cry...A new coordination polymer,Zn(bpy)L(BUC‐21),(H2L=cis‐1,3‐dibenzyl‐2‐imidazolidone‐4,5‐dicarboxylic acid,bpy=4,4′‐bipyridine),has been synthesized under hydrothermal conditions,and characterized by single‐crystal X‐ray analysis,Fourier transform infrared spectroscopy,thermogravimetric analyses,CNH elemental analysis and UV‐Vis diffuse reflectance spectroscopy.BUC‐21exhibited an excellent performance for photocatalytic Cr(VI)reduction with a conversion efficiency of96%,better than that of commercial P25(39%),under UV light irradiation for30min.BUC‐21could also be used to conduct photocatalytic degradation of organic dyes including methylene blue,rhodamine B,methyl orange and reactive red X‐3B.Also,the photocatalytic activity of BUC‐21remained high across a wide pH range from2.0to12.0.It is interesting to note,however,that BUC‐21was unable to achieve simultaneous reduction of Cr(VI)and degradation of an organic pollutant in a mixed matrix,which can be attributed to the competition between Cr(VI)and the organic dyes for access to the photo‐excited electrons.展开更多
Acrylonitrile-methyl methacrylate （AN-MMA） copolymer/silica nanocomposites were synthesized by in-situ emulsion polymerization initiated by 2,2＇-azobis（2-amidinopropane） dihydrochloride absorbed onto colloidal si...Acrylonitrile-methyl methacrylate （AN-MMA） copolymer/silica nanocomposites were synthesized by in-situ emulsion polymerization initiated by 2,2＇-azobis（2-amidinopropane） dihydrochloride absorbed onto colloidal silica particles, and the mesoporous carbon materials were prepared through carbonization of the obtained AN-MMA copolymer/silica nanocomposites, followed by HF etching. Thermogravimetric analysis of AN-MMAcopolymer/silica nanocomposltes snoweO mat me caroon ylelCl or copolymer was slgnuy oecreaseo as Silica parucle incorporated. N2 adsorption-desorption, scan electron microscopy （SEM） and transmission electron microscopy （TEM） were used to characterize the structure and morphology of the mesoporous carbon materials. Both SEM and展开更多
We report a facile coagglomeration method for preparing graphene (G)/MgCl2‐supported Ti‐based Ziegler‐Natta catalysts. The effects of graphene feed ratio on catalyst morphology and ethylene polymerization behavior ...We report a facile coagglomeration method for preparing graphene (G)/MgCl2‐supported Ti‐based Ziegler‐Natta catalysts. The effects of graphene feed ratio on catalyst morphology and ethylene polymerization behavior were examined. The synthesized catalyst exhibited very high activity for ethylene polymerization. The resultant polyethylene (PE)/G nanocomposites showed a layered morphology, and the graphene fillers were well dispersed in the PE matrix. In addition, the thermal stability and mechanical properties of PE were significantly enhanced with the introduction of a very small amount of G fillers (0.05 wt%). This work provides a facile approach to the production o fhigh‐performance PE.展开更多
Most of traditional linear poly(ethylene terephthalate)(PET)resins of relatively low molecular mass and narrow molecular mass distribution have low melt strength at foaming temperatures,which are not enough to support...Most of traditional linear poly(ethylene terephthalate)(PET)resins of relatively low molecular mass and narrow molecular mass distribution have low melt strength at foaming temperatures,which are not enough to support and keep cells.An in-situ polymerization-modification process with esterification and polycondensation stages was performed in a 2 L batch stirred reactor using pyromellitic dianhydride(PMDA)or pentaerythritol(PENTA)as modifying monomers to obtain PETs with high melt strength.The influence of amounts of modifying monomers on the properties of modified PET was investigated.It was found that the selected modifying monomers could effectively introduce branched structures into the modified PETs and improve their melt strength.With increasing the amount of the modifying monomer,the melt strength of the modified PET increased.But when the amount of PENTA reached 0.35%or PMDA reached 0.9%,crosslinking phenomenon was observed in the modified PET.Supercritical carbon dioxide(ScCO2)was employed as physical foaming agent to evaluate the foaming ability of modified PETs.The modified PETs had good foaming properties at 14 MPa of CO2pressure with foaming temperature ranging from 265°C to 280°C.SEM micrographs demonstrated that both modified PET foams had homogeneous cellular structures,with cell diameter ranging from 35μm to 49μm for PENTA modified PETs and38μm to 57μm for PMDA modified ones.Correspondingly,the cell density had a range of 3.5×107cells·cm 3to 7×106cells·cm 3for the former and 2.8×107cells·cm 3to 5.8×106cells·cm 3for the latter.展开更多
The conjugated polymer-based solar cell is one of the most promising devices in search of sustainable, renewable energy sources in last decade. It is the youngest field in organic solar cell research and also is certa...The conjugated polymer-based solar cell is one of the most promising devices in search of sustainable, renewable energy sources in last decade. It is the youngest field in organic solar cell research and also is certainly the fastest growing one at the moment. In addition, the key factor for polymer-based solar cells with high-efficiency is to invent new materials. Organic solar cell has attracted significant researches and commercial interest due to its low cost in fabrication and flexibility in applications. However, they suffer from relatively low conversion efficiency. The summarization of the significance and concept of high efficiency polymer solar cell technologies are presented.展开更多
The oxygen reduction reaction(ORR)on the cathode of a polymer electrolyte fuel cell requires the use of a catalyst based on Pt,one of the most expensive metals on the earth.A number of strategies,including optimizatio...The oxygen reduction reaction(ORR)on the cathode of a polymer electrolyte fuel cell requires the use of a catalyst based on Pt,one of the most expensive metals on the earth.A number of strategies,including optimization of a different metal into the core,have been investigated to enhance the activity of a Pt-based catalyst and thus reduce the loading of Pt.By dedicating to compounding high catalytic activity Pt_(2.7)Pd_(0.3)Ni concave cubic with high index crystal face,the paper shows that concave structures can offer more active site and high level of catalytic activity and if mixed with other metal,decrease the proportion of Pt and improve its mass activity.The paper also makes an exploration into the theory and conditions behind the formation of Pt_(2.7)Pd_(0.3)Ni concave cubic structure,and investigates the difference it demonstrates by modifying the reactive conditions.The results of the oxygen reduction performance of the electrochemical test are as follows:the concave cube-shaped Pt-Pd-Ni catalyst has a mass activity of 1.28 A mg_(Pt)^(–1) at 0.9 V,its highest mass activity is 8.20 times that of commercial Pt/C,and its specific activity is 8.68 times of that commercial Pt/C.And the Pt-Pd-Ni ternary nanocage has excellent structural invariance.After the stability test,there is no obvious structural change and performance degradation in the nanostructure.展开更多
The liquid bulk technology can be divided into four parts： raw material refining, polymerization, flashed to live, granulation and packaging. There is an intrinsic link between them. This passage mainly makes some ex...The liquid bulk technology can be divided into four parts： raw material refining, polymerization, flashed to live, granulation and packaging. There is an intrinsic link between them. This passage mainly makes some experimental results to show that the process of raw material refining and polymerization.展开更多
A PANI/WO3@cotton thread-based flexible sensor that is capable of detecting NH3 at room temperature is developed here.A layer of WO3 with PANI nanoparticles can be deposited by in-situ polymerization.The morphology an...A PANI/WO3@cotton thread-based flexible sensor that is capable of detecting NH3 at room temperature is developed here.A layer of WO3 with PANI nanoparticles can be deposited by in-situ polymerization.The morphology and structure of the specimens were investigated by utilizing TEM,SEM,XRD and FTIR.The sensing performance of the PANI/WO3@cotton sensors with different WO3 molar ratios to NH3 at room temperature was examined.The results show that the optimal sensor(10 mol%WO3)has a response of 6.0 to 100 ppm NH3,which is significantly higher than that of the sensors based on pristine PANI and other composites.The PANI/WO3@cotton sensor also displays excellent selectivity,gas response,and flexibility even at room temperature.The unique fiber structure,p-n heterojunction,and the increased protonation of PANI in the composites contribute to the enhanced sensing property.展开更多
基金Project supported by Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions, Ministry of Education, China
文摘A kind of nanokaolin powder with a thickness of 20-50nm and an average diameter of 300nm is produced through combined procedure of purification, delamination, surface modification and pulverization. The application experiments in butadiene rubber (BR), ethylene-propylene diene methylene (EPDM), and natural rubber (NR) indicates that this nano-kaolin powder material is much better than precipitated silica in reinforcement, while in styrene-butadiene rubber (SBR) it is close to precipitated silica. Nanokaolin is of superiority in elasticity, elongation at break, anti-flexure property.
基金supported by the National Natural Science Foundation of China(51578034)the Beijing Natural Science Foundation&Scientific Research Key Program of Beijing Municipal Commission of Education(KZ201410016018)+1 种基金Beijing Talent Project(2016023)Project of Construction of Innovative Teams and Teacher Career Development for Universities and Colleges Under Beijing Municipality(IDHT20170508)~~
文摘A new coordination polymer,Zn(bpy)L(BUC‐21),(H2L=cis‐1,3‐dibenzyl‐2‐imidazolidone‐4,5‐dicarboxylic acid,bpy=4,4′‐bipyridine),has been synthesized under hydrothermal conditions,and characterized by single‐crystal X‐ray analysis,Fourier transform infrared spectroscopy,thermogravimetric analyses,CNH elemental analysis and UV‐Vis diffuse reflectance spectroscopy.BUC‐21exhibited an excellent performance for photocatalytic Cr(VI)reduction with a conversion efficiency of96%,better than that of commercial P25(39%),under UV light irradiation for30min.BUC‐21could also be used to conduct photocatalytic degradation of organic dyes including methylene blue,rhodamine B,methyl orange and reactive red X‐3B.Also,the photocatalytic activity of BUC‐21remained high across a wide pH range from2.0to12.0.It is interesting to note,however,that BUC‐21was unable to achieve simultaneous reduction of Cr(VI)and degradation of an organic pollutant in a mixed matrix,which can be attributed to the competition between Cr(VI)and the organic dyes for access to the photo‐excited electrons.
基金Supported by the Program for New Century Excellent Talents in University (NCET-07-0738)
文摘Acrylonitrile-methyl methacrylate （AN-MMA） copolymer/silica nanocomposites were synthesized by in-situ emulsion polymerization initiated by 2,2＇-azobis（2-amidinopropane） dihydrochloride absorbed onto colloidal silica particles, and the mesoporous carbon materials were prepared through carbonization of the obtained AN-MMA copolymer/silica nanocomposites, followed by HF etching. Thermogravimetric analysis of AN-MMAcopolymer/silica nanocomposltes snoweO mat me caroon ylelCl or copolymer was slgnuy oecreaseo as Silica parucle incorporated. N2 adsorption-desorption, scan electron microscopy （SEM） and transmission electron microscopy （TEM） were used to characterize the structure and morphology of the mesoporous carbon materials. Both SEM and
基金supported by the National Research Foundation of Korea (NRF-2015R1D1A1A0161012)the National Natural Science Foundation of China (U1462124)~~
文摘We report a facile coagglomeration method for preparing graphene (G)/MgCl2‐supported Ti‐based Ziegler‐Natta catalysts. The effects of graphene feed ratio on catalyst morphology and ethylene polymerization behavior were examined. The synthesized catalyst exhibited very high activity for ethylene polymerization. The resultant polyethylene (PE)/G nanocomposites showed a layered morphology, and the graphene fillers were well dispersed in the PE matrix. In addition, the thermal stability and mechanical properties of PE were significantly enhanced with the introduction of a very small amount of G fillers (0.05 wt%). This work provides a facile approach to the production o fhigh‐performance PE.
基金Supported by the National Natural Science Foundation of China（21176070） the National High Technology Research and Development Program of China（2012AA040211）+2 种基金 the Joint Research Project of Yangtze River Delta（12195810900） the Specialized Research Fund for the Doctoral Program of Higher Education（20120074120019） the Fundamental Research Funds for the Central Universities
文摘Most of traditional linear poly(ethylene terephthalate)(PET)resins of relatively low molecular mass and narrow molecular mass distribution have low melt strength at foaming temperatures,which are not enough to support and keep cells.An in-situ polymerization-modification process with esterification and polycondensation stages was performed in a 2 L batch stirred reactor using pyromellitic dianhydride(PMDA)or pentaerythritol(PENTA)as modifying monomers to obtain PETs with high melt strength.The influence of amounts of modifying monomers on the properties of modified PET was investigated.It was found that the selected modifying monomers could effectively introduce branched structures into the modified PETs and improve their melt strength.With increasing the amount of the modifying monomer,the melt strength of the modified PET increased.But when the amount of PENTA reached 0.35%or PMDA reached 0.9%,crosslinking phenomenon was observed in the modified PET.Supercritical carbon dioxide(ScCO2)was employed as physical foaming agent to evaluate the foaming ability of modified PETs.The modified PETs had good foaming properties at 14 MPa of CO2pressure with foaming temperature ranging from 265°C to 280°C.SEM micrographs demonstrated that both modified PET foams had homogeneous cellular structures,with cell diameter ranging from 35μm to 49μm for PENTA modified PETs and38μm to 57μm for PMDA modified ones.Correspondingly,the cell density had a range of 3.5×107cells·cm 3to 7×106cells·cm 3for the former and 2.8×107cells·cm 3to 5.8×106cells·cm 3for the latter.
文摘The conjugated polymer-based solar cell is one of the most promising devices in search of sustainable, renewable energy sources in last decade. It is the youngest field in organic solar cell research and also is certainly the fastest growing one at the moment. In addition, the key factor for polymer-based solar cells with high-efficiency is to invent new materials. Organic solar cell has attracted significant researches and commercial interest due to its low cost in fabrication and flexibility in applications. However, they suffer from relatively low conversion efficiency. The summarization of the significance and concept of high efficiency polymer solar cell technologies are presented.
文摘The oxygen reduction reaction(ORR)on the cathode of a polymer electrolyte fuel cell requires the use of a catalyst based on Pt,one of the most expensive metals on the earth.A number of strategies,including optimization of a different metal into the core,have been investigated to enhance the activity of a Pt-based catalyst and thus reduce the loading of Pt.By dedicating to compounding high catalytic activity Pt_(2.7)Pd_(0.3)Ni concave cubic with high index crystal face,the paper shows that concave structures can offer more active site and high level of catalytic activity and if mixed with other metal,decrease the proportion of Pt and improve its mass activity.The paper also makes an exploration into the theory and conditions behind the formation of Pt_(2.7)Pd_(0.3)Ni concave cubic structure,and investigates the difference it demonstrates by modifying the reactive conditions.The results of the oxygen reduction performance of the electrochemical test are as follows:the concave cube-shaped Pt-Pd-Ni catalyst has a mass activity of 1.28 A mg_(Pt)^(–1) at 0.9 V,its highest mass activity is 8.20 times that of commercial Pt/C,and its specific activity is 8.68 times of that commercial Pt/C.And the Pt-Pd-Ni ternary nanocage has excellent structural invariance.After the stability test,there is no obvious structural change and performance degradation in the nanostructure.
文摘The liquid bulk technology can be divided into four parts： raw material refining, polymerization, flashed to live, granulation and packaging. There is an intrinsic link between them. This passage mainly makes some experimental results to show that the process of raw material refining and polymerization.
基金This work was supported by the National Natural Science Foundation of China(61471233).
文摘A PANI/WO3@cotton thread-based flexible sensor that is capable of detecting NH3 at room temperature is developed here.A layer of WO3 with PANI nanoparticles can be deposited by in-situ polymerization.The morphology and structure of the specimens were investigated by utilizing TEM,SEM,XRD and FTIR.The sensing performance of the PANI/WO3@cotton sensors with different WO3 molar ratios to NH3 at room temperature was examined.The results show that the optimal sensor(10 mol%WO3)has a response of 6.0 to 100 ppm NH3,which is significantly higher than that of the sensors based on pristine PANI and other composites.The PANI/WO3@cotton sensor also displays excellent selectivity,gas response,and flexibility even at room temperature.The unique fiber structure,p-n heterojunction,and the increased protonation of PANI in the composites contribute to the enhanced sensing property.
