Polystyrene(PS)is rich in plastic materials,but it produces a large amount of waste every year,causing a huge burden on the environment.Although PS plastic is the source of a common"white pollution"in daily ...Polystyrene(PS)is rich in plastic materials,but it produces a large amount of waste every year,causing a huge burden on the environment.Although PS plastic is the source of a common"white pollution"in daily life,it still has a high utilization value.At the same time,the flammability of PS material determines that it cannot be applicated in places where fire accidents occur frequently.As a result,its application has been greatly limited.In order to realize the efficient utilization of waste PS and broaden its scope of application,PS was modified by hyper-crosslinking in order to improve its fire-retardant performance.In this method,the PS solution with high purity was obtained by dissolving waste PS foam with 1,2-dichloroethane(DCE),and then the hyper-crosslinked polymer with high specific surface area was prepared by adding cross-linking agent formaldehyde dimethyl acetal(FDA)and a Lewis-acid catalyst ferric chloride(FeCl_(3)).Further studies showed that the effects of the amount of cross-linking agent FDA,catalyst FeCl_(3) and PS on the reaction products were different.In addition,compared the as-prepared fire-retardant materials with PS foam from the aspects of flame retardancy and thermal insulation,it can be concluded that the fire-retardant performance of the materials prepared by this method has been significantly enhanced.And it is proved that this method is feasible towards the preparation of a large number of fire-retardant composite materials by using a scale-up experiment.展开更多
Conjugated microporous polymers have excellent skeleton structures but poor electrical conductivity limits their applications in microwave absorption.To solve this problem,a strategy of molecular expansion and confini...Conjugated microporous polymers have excellent skeleton structures but poor electrical conductivity limits their applications in microwave absorption.To solve this problem,a strategy of molecular expansion and confining polymerization is proposed in this work to synthesize conductive hyper-crosslinked conjugated microporous polymer.The topology of the conjugated microporous polymer is changed into a three-dimensional skeleton structure with high specific surface area by using molecular expansion technique,and the controlled growth of polypyrrole in the channel constructs a unique network structure.The balance of excellent composite backbone structure,proper conductivity,attenuation capability and impedance matching enable the material to exhibit electromagnetic wave absorption performance.As a result,with low filler loading of 10 wt%,a strongest reflection loss of-52.68 d B and a maximum effective bandwidth of 5.76 GHz.Additionally,CST simulations of the radar scattering cross section have been carried out to verify the excellent material properties.This study provides new concepts for new conductive polymers and broadens the application of hyper-crosslinked conjugated microporous polymer in the field of electromagnetic wave absorption.展开更多
In this work,Fe/Ru-catalyst supported on hyper-crosslinked polystyrene(HPS)synthesized via hydrothermal deposition was proposed for the FischerTropsch synthesis(FTS)to obtain a high yield of gasolineranged hydrocarbon...In this work,Fe/Ru-catalyst supported on hyper-crosslinked polystyrene(HPS)synthesized via hydrothermal deposition was proposed for the FischerTropsch synthesis(FTS)to obtain a high yield of gasolineranged hydrocarbons.According to the characterization results,the obtained monometallic 2%Fe-HPS catalyst contains Fe_(3)O_(4)particles with a multimodal distribution(mean particle size of 11,30,and 45 nm).The addition of Ru leads to a decrease in the particle size with a narrower distribution(ca.5 nm).Ru was shown to serve as a nucleating agent for Fe_(3)O_(4)crystalline since it has a higher affinity to the HPS surface and strongly anchors to the benzene rings of the polymer.This prevents a leaching of the active phase from the support increasing the catalyst stability.Ru addition also brings supplemental sites for CO and H_(2) chemisorption resulting in 1.5-fold increased activity in FTS reaction compared to monometallic 2%FeHPS composite.2%Fe-1%Ru-HPS composite showed~20%higher selectivity toward the formation of C_(5)-C_(11) alkanes at about 30%conversion of CO in comparison with monometallic one.Moreover,the branched hydrocarbons with a selectivity of approximately 17.5 mol%were observed in the FTS products in the presence of a 2%Fe-1%Ru-HPS catalyst.展开更多
Porous carbon(PC)materials have unique structures and excellent physicochemical properties,which offer significant advantages in the field of electromagnetic wave(EMW)absorption materials.However,how to utilize availa...Porous carbon(PC)materials have unique structures and excellent physicochemical properties,which offer significant advantages in the field of electromagnetic wave(EMW)absorption materials.However,how to utilize available raw materials and practical preparation techniques is a major challenge for PC microwave absorption materials to achieve engineering applications.In this study,inexpensive coal tar pitch(CTP)was used as a carbon source to prepare PC microwave absorbers.Firstly,hyper-crosslinked polymers(HCPs)were prepared by selectively crosslinking the aromatic components in CTP via Friedel-Crafts reaction using chloroalkanes as crosslinking agents.Further,PC materials with uniform structure were also prepared by simple high-temperature carbonization.The effects of cross-linker type(CH_(2)Cl_(2),CHCl_(3) and CCl_(4))and carbonization temperature(600,700,and 800℃)on the microstructure,crystallization,dielectric and microwave absorption properties of PC materials were systematically studied.After modulation and optimization,all CTP-based PCs have uniform pore structure with a maximum specific surface area of 533.93 m^(2)/g.The PC with CHCl_(3) as cross-linking agent carbonized at 700℃ showed the exceptional microwave absorption performance,with the minimum refection loss(RL_(min))of−43.08 dB and the maximum effective absorption bandwidth(EAB_(max))of 5.44 GHz.Meanwhile,the RL_(min) of CCl_(4)-PC-800 also achieved−47.28 dB.This work has developed a simple and low-cost method for preparing PC microwave absorption materials,which has the potential to enable the mass production and engineering application of PCs,as well as facilitating processing technology innovation and high value-added utilization of CTP.展开更多
Polystyrene crosslinked microspheres were prepared by soap-free emulsion polymerization using styrene (St) and divinylbenzene (DVB) as monomers;then,the microporous structure was knitted by the Friedel-Crafts alkylati...Polystyrene crosslinked microspheres were prepared by soap-free emulsion polymerization using styrene (St) and divinylbenzene (DVB) as monomers;then,the microporous structure was knitted by the Friedel-Crafts alkylation reaction,and the Au nanoparticles (AuNPs) were loaded into the pores through thermal reduction,to obtain AuNPs/ hyper-crosslinked microporous polymer composite microspheres.SEM and particle-size test results show that the microspheres show good monodispersity.The micropore analysis indicates that the specific surface area and the pore volume of the microporous polymer microspheres decrease with increasing DVB content,and when the DVB content is 0.1%,the specific surface area reaches a maximum of 1 174.6 m2/g.After loading AuNPs,the specific surface area and the amount of micropores of the composite microspheres decrease obviously.The results of XRD and XPS analyses suggest that HAuCl4 is reduced to AuNPs.The composite microspheres show a good catalytic performance for the reduction catalyst of 4-nitrophenol.展开更多
Carbon molecular sieve membranes(CMSMs)are a class of porous membranes inherited with excellent thermal stability,high tolerance and superior mechanical strength.Owing to their nanoporous structures,CMSMs usually hold...Carbon molecular sieve membranes(CMSMs)are a class of porous membranes inherited with excellent thermal stability,high tolerance and superior mechanical strength.Owing to their nanoporous structures,CMSMs usually hold significant potential for gas separation applications.Specifically,hyper-crosslinked ionic polymer(HIP)membranes possess a highly crosslinked nitrogen-rich framework,high thermal stability together with exceptional mechanical strength,making them excellent precursors for the CMSMs fabrication.Upon pyrolysis of HIP membranes,the resulting CMSMs featured with nitrogen functional sites exhibit strong interactions with CO_(2),which significantly reduces the CO_(2)permeability while other gas molecules continue to flow through the nanoporous membrane.The resultant CMSMs exhibited excellent H_(2)/CO_(2)selectivity with values of 10.75 and 7.09,together with ultra-high H_(2)permeability of 3052 and 9181 barrer,respectively,surpassing the Robeson upper bound.The preparation route towards CMSMs with high nitrogen content from HIP can significantly enrich the rational design and synthesis strategies of high-performance gas separation CMSM materials.展开更多
Separation media that combine the desired material properties within a single material for a given process remain an ongoing challenge for the gas separations in industry.Process integration of porous solid adsorbents...Separation media that combine the desired material properties within a single material for a given process remain an ongoing challenge for the gas separations in industry.Process integration of porous solid adsorbents is difficult due to their limited volumetric capacity,whereas issues of volatility and high regeneration temperatures exist for liquid amines and physical solvents.Herein,we report a family of polymer liquids inspired by hyper-crosslinked polymers(HCPs),a class of highly swellable network polymers.Compared with a chemically similar porous solid,the HCP-liquids demonstrate good volumetric capacity and improved selectivity of carbon dioxide over methane.Uptake appears to be enhanced by intramolecular swelling of the HCP-liquids at elevated pressures,while vips are strongly rejected from the HCP-liquids at slightly elevated temperatures,leading to highly efficient regeneration.Heat of adsorption and specific heat capacity of the HCP-liquids are also low,further suggesting favourable process thermodynamics.Additionally being easily prepared at scale,the presented HCP-liquids represent a promising step towards a material with the requisite properties to replace conventional scrubbing solvents to drastically reduce the footprint and energy needs of gas separations.展开更多
Fluorinated porous organic networks(F-PONs)have demonstrated unique properties and applications,but approaches capable of affording F-PONs with high fluorine content and robust nanoporous architecture under metal-free...Fluorinated porous organic networks(F-PONs)have demonstrated unique properties and applications,but approaches capable of affording F-PONs with high fluorine content and robust nanoporous architecture under metal-free and easy handling conditions are still rarely reported.Herein,using polydivinylbenzene(PDVB)as an easily available precursor,a novel and straightforward approach was developed to afford F-PONs via a dehydrative Friedel-Crafts reaction using perfluorinated benzylic alcohols as the cross-linking agent promoted by Bronsted acid(trifluoromethanesulfonic acid).The afforded material(F-PDVB)featured high fluorine content(22 at.%),large surface area(771 m^(2)·g^(-1)),and good chemical/thermal stability,rendering them as promising candidates for the adsorption of CO_(2),hydrocarbons,fluorocarbons,and chlorofluorocarbons,with weight capacities up to 520 wt.%being achieved.This simple methodology can be extended to fabricate fluorinated hyper-crosslinked polymers(F-HCPs)from rigid aromatic monomers.The progress made in this work will open new opportunities to further expand the involvement of fluorinated materials in large scale applications.展开更多
Both bottle-point and column-feeding experi-ments involving different solutes and sorbents were carried out to investigate the adsorption selectivity and separation performance of salicylic acid and 5-sulfosalicylic a...Both bottle-point and column-feeding experi-ments involving different solutes and sorbents were carried out to investigate the adsorption selectivity and separation performance of salicylic acid and 5-sulfosalicylic acid.Their adsorption isotherms onto such hypercrosslinked polymeric adsorbents as NDA-100 and NDA-99 could be well described by the Freundlich equations whose characteristics describe extrathermic and favorable adsorption processes.The adsorp-tion towards NDA-100 mainly depended on the p-p interac-tion,while that towards NDA-99 was extremely influenced by the static-electric interaction.Additionally,the adsorptive capacity of salicylic acid on NDA-99 decreased while it increased on NDA-100 with the presence of 5-sulfosalicylic acid in the adsorptive environment as the competitive component.Comparatively,the adsorption capacity of 5-sulfosalicylic acid decreased on both resins with salicylic acid as the competitive component.In fact,the difference in the interaction between adsorbent and adsorbate resulted in the straight antagonism on the effective adsorption sites on the adsorbent.In conclusion,the adsorption selectivity of salicylic acid onto NDA-100 was obviously larger than that onto NDA-99 with the existence of 5-sulfosalicylic acid in the adsorptive environment.A satisfactory separation and recovery of tested solutes in aqueous phase could be foresee-ably achieved by the sequencing adsorption technique involving NDA-100 as well as NDA-99.展开更多
基金Thanks for financial support from the National Natural Science Foun-dation of China(No.51906252)the Natural Science Foundation of Jiangsu Province(NO.BK20190632)China Postdoctoral Science Foun-dation(2019M661980).
文摘Polystyrene(PS)is rich in plastic materials,but it produces a large amount of waste every year,causing a huge burden on the environment.Although PS plastic is the source of a common"white pollution"in daily life,it still has a high utilization value.At the same time,the flammability of PS material determines that it cannot be applicated in places where fire accidents occur frequently.As a result,its application has been greatly limited.In order to realize the efficient utilization of waste PS and broaden its scope of application,PS was modified by hyper-crosslinking in order to improve its fire-retardant performance.In this method,the PS solution with high purity was obtained by dissolving waste PS foam with 1,2-dichloroethane(DCE),and then the hyper-crosslinked polymer with high specific surface area was prepared by adding cross-linking agent formaldehyde dimethyl acetal(FDA)and a Lewis-acid catalyst ferric chloride(FeCl_(3)).Further studies showed that the effects of the amount of cross-linking agent FDA,catalyst FeCl_(3) and PS on the reaction products were different.In addition,compared the as-prepared fire-retardant materials with PS foam from the aspects of flame retardancy and thermal insulation,it can be concluded that the fire-retardant performance of the materials prepared by this method has been significantly enhanced.And it is proved that this method is feasible towards the preparation of a large number of fire-retardant composite materials by using a scale-up experiment.
基金financially supported by the National Natural Science Foundation of China(No.52273267)the Fundamental Research Funds for the Central Universities(Nos.30920041102 and 30920021107)。
文摘Conjugated microporous polymers have excellent skeleton structures but poor electrical conductivity limits their applications in microwave absorption.To solve this problem,a strategy of molecular expansion and confining polymerization is proposed in this work to synthesize conductive hyper-crosslinked conjugated microporous polymer.The topology of the conjugated microporous polymer is changed into a three-dimensional skeleton structure with high specific surface area by using molecular expansion technique,and the controlled growth of polypyrrole in the channel constructs a unique network structure.The balance of excellent composite backbone structure,proper conductivity,attenuation capability and impedance matching enable the material to exhibit electromagnetic wave absorption performance.As a result,with low filler loading of 10 wt%,a strongest reflection loss of-52.68 d B and a maximum effective bandwidth of 5.76 GHz.Additionally,CST simulations of the radar scattering cross section have been carried out to verify the excellent material properties.This study provides new concepts for new conductive polymers and broadens the application of hyper-crosslinked conjugated microporous polymer in the field of electromagnetic wave absorption.
基金funded by the Russian Science Foundation(Grant No.23-23-00653).
文摘In this work,Fe/Ru-catalyst supported on hyper-crosslinked polystyrene(HPS)synthesized via hydrothermal deposition was proposed for the FischerTropsch synthesis(FTS)to obtain a high yield of gasolineranged hydrocarbons.According to the characterization results,the obtained monometallic 2%Fe-HPS catalyst contains Fe_(3)O_(4)particles with a multimodal distribution(mean particle size of 11,30,and 45 nm).The addition of Ru leads to a decrease in the particle size with a narrower distribution(ca.5 nm).Ru was shown to serve as a nucleating agent for Fe_(3)O_(4)crystalline since it has a higher affinity to the HPS surface and strongly anchors to the benzene rings of the polymer.This prevents a leaching of the active phase from the support increasing the catalyst stability.Ru addition also brings supplemental sites for CO and H_(2) chemisorption resulting in 1.5-fold increased activity in FTS reaction compared to monometallic 2%FeHPS composite.2%Fe-1%Ru-HPS composite showed~20%higher selectivity toward the formation of C_(5)-C_(11) alkanes at about 30%conversion of CO in comparison with monometallic one.Moreover,the branched hydrocarbons with a selectivity of approximately 17.5 mol%were observed in the FTS products in the presence of a 2%Fe-1%Ru-HPS catalyst.
基金supported by the National Natural Science Foundation of China(No.22005039)the Innovation Capability Support Program of Shaanxi(No.2023-CX-TD-43)the Fundamental Research Funds for the Central Universities,CHD(Nos.300102313208,300102312403,and 300102314401).
文摘Porous carbon(PC)materials have unique structures and excellent physicochemical properties,which offer significant advantages in the field of electromagnetic wave(EMW)absorption materials.However,how to utilize available raw materials and practical preparation techniques is a major challenge for PC microwave absorption materials to achieve engineering applications.In this study,inexpensive coal tar pitch(CTP)was used as a carbon source to prepare PC microwave absorbers.Firstly,hyper-crosslinked polymers(HCPs)were prepared by selectively crosslinking the aromatic components in CTP via Friedel-Crafts reaction using chloroalkanes as crosslinking agents.Further,PC materials with uniform structure were also prepared by simple high-temperature carbonization.The effects of cross-linker type(CH_(2)Cl_(2),CHCl_(3) and CCl_(4))and carbonization temperature(600,700,and 800℃)on the microstructure,crystallization,dielectric and microwave absorption properties of PC materials were systematically studied.After modulation and optimization,all CTP-based PCs have uniform pore structure with a maximum specific surface area of 533.93 m^(2)/g.The PC with CHCl_(3) as cross-linking agent carbonized at 700℃ showed the exceptional microwave absorption performance,with the minimum refection loss(RL_(min))of−43.08 dB and the maximum effective absorption bandwidth(EAB_(max))of 5.44 GHz.Meanwhile,the RL_(min) of CCl_(4)-PC-800 also achieved−47.28 dB.This work has developed a simple and low-cost method for preparing PC microwave absorption materials,which has the potential to enable the mass production and engineering application of PCs,as well as facilitating processing technology innovation and high value-added utilization of CTP.
基金the National Natural Science Foundation of China(No.51303049)。
文摘Polystyrene crosslinked microspheres were prepared by soap-free emulsion polymerization using styrene (St) and divinylbenzene (DVB) as monomers;then,the microporous structure was knitted by the Friedel-Crafts alkylation reaction,and the Au nanoparticles (AuNPs) were loaded into the pores through thermal reduction,to obtain AuNPs/ hyper-crosslinked microporous polymer composite microspheres.SEM and particle-size test results show that the microspheres show good monodispersity.The micropore analysis indicates that the specific surface area and the pore volume of the microporous polymer microspheres decrease with increasing DVB content,and when the DVB content is 0.1%,the specific surface area reaches a maximum of 1 174.6 m2/g.After loading AuNPs,the specific surface area and the amount of micropores of the composite microspheres decrease obviously.The results of XRD and XPS analyses suggest that HAuCl4 is reduced to AuNPs.The composite microspheres show a good catalytic performance for the reduction catalyst of 4-nitrophenol.
基金supported by the Fundamental Research Funds for the Central Universities(2232022A-03 and 2232024Y-01)the National Natural Science Foundation of China(22102021,22375037,52073046,52373172,and 52103106)+2 种基金the National Key Research and Development Program of China(2022YFB3807100,2022YFB3807102,and 2022YFB3807103)the Program of Shanghai Academic Research Leader(21XD1420200)the Natural Science Foundation of Shanghai(23ZR1401100 and 21ZR1402700).
文摘Carbon molecular sieve membranes(CMSMs)are a class of porous membranes inherited with excellent thermal stability,high tolerance and superior mechanical strength.Owing to their nanoporous structures,CMSMs usually hold significant potential for gas separation applications.Specifically,hyper-crosslinked ionic polymer(HIP)membranes possess a highly crosslinked nitrogen-rich framework,high thermal stability together with exceptional mechanical strength,making them excellent precursors for the CMSMs fabrication.Upon pyrolysis of HIP membranes,the resulting CMSMs featured with nitrogen functional sites exhibit strong interactions with CO_(2),which significantly reduces the CO_(2)permeability while other gas molecules continue to flow through the nanoporous membrane.The resultant CMSMs exhibited excellent H_(2)/CO_(2)selectivity with values of 10.75 and 7.09,together with ultra-high H_(2)permeability of 3052 and 9181 barrer,respectively,surpassing the Robeson upper bound.The preparation route towards CMSMs with high nitrogen content from HIP can significantly enrich the rational design and synthesis strategies of high-performance gas separation CMSM materials.
基金funding from Australian research council(F T1301000345)。
文摘Separation media that combine the desired material properties within a single material for a given process remain an ongoing challenge for the gas separations in industry.Process integration of porous solid adsorbents is difficult due to their limited volumetric capacity,whereas issues of volatility and high regeneration temperatures exist for liquid amines and physical solvents.Herein,we report a family of polymer liquids inspired by hyper-crosslinked polymers(HCPs),a class of highly swellable network polymers.Compared with a chemically similar porous solid,the HCP-liquids demonstrate good volumetric capacity and improved selectivity of carbon dioxide over methane.Uptake appears to be enhanced by intramolecular swelling of the HCP-liquids at elevated pressures,while vips are strongly rejected from the HCP-liquids at slightly elevated temperatures,leading to highly efficient regeneration.Heat of adsorption and specific heat capacity of the HCP-liquids are also low,further suggesting favourable process thermodynamics.Additionally being easily prepared at scale,the presented HCP-liquids represent a promising step towards a material with the requisite properties to replace conventional scrubbing solvents to drastically reduce the footprint and energy needs of gas separations.
基金supported financially by the Division of Chemical Sciences,Geosciences,and Biosciences,Office of Basic Energy Sciences,US Department of Energy.
文摘Fluorinated porous organic networks(F-PONs)have demonstrated unique properties and applications,but approaches capable of affording F-PONs with high fluorine content and robust nanoporous architecture under metal-free and easy handling conditions are still rarely reported.Herein,using polydivinylbenzene(PDVB)as an easily available precursor,a novel and straightforward approach was developed to afford F-PONs via a dehydrative Friedel-Crafts reaction using perfluorinated benzylic alcohols as the cross-linking agent promoted by Bronsted acid(trifluoromethanesulfonic acid).The afforded material(F-PDVB)featured high fluorine content(22 at.%),large surface area(771 m^(2)·g^(-1)),and good chemical/thermal stability,rendering them as promising candidates for the adsorption of CO_(2),hydrocarbons,fluorocarbons,and chlorofluorocarbons,with weight capacities up to 520 wt.%being achieved.This simple methodology can be extended to fabricate fluorinated hyper-crosslinked polymers(F-HCPs)from rigid aromatic monomers.The progress made in this work will open new opportunities to further expand the involvement of fluorinated materials in large scale applications.
基金The work was supported by the Opening Fund of Key Laboratory of Environmental Engineering of Jiangsu Province,China(Grant No.KF0502)by the Opening Fund of Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection(Grant No.JLCBE05005).
文摘Both bottle-point and column-feeding experi-ments involving different solutes and sorbents were carried out to investigate the adsorption selectivity and separation performance of salicylic acid and 5-sulfosalicylic acid.Their adsorption isotherms onto such hypercrosslinked polymeric adsorbents as NDA-100 and NDA-99 could be well described by the Freundlich equations whose characteristics describe extrathermic and favorable adsorption processes.The adsorp-tion towards NDA-100 mainly depended on the p-p interac-tion,while that towards NDA-99 was extremely influenced by the static-electric interaction.Additionally,the adsorptive capacity of salicylic acid on NDA-99 decreased while it increased on NDA-100 with the presence of 5-sulfosalicylic acid in the adsorptive environment as the competitive component.Comparatively,the adsorption capacity of 5-sulfosalicylic acid decreased on both resins with salicylic acid as the competitive component.In fact,the difference in the interaction between adsorbent and adsorbate resulted in the straight antagonism on the effective adsorption sites on the adsorbent.In conclusion,the adsorption selectivity of salicylic acid onto NDA-100 was obviously larger than that onto NDA-99 with the existence of 5-sulfosalicylic acid in the adsorptive environment.A satisfactory separation and recovery of tested solutes in aqueous phase could be foresee-ably achieved by the sequencing adsorption technique involving NDA-100 as well as NDA-99.
