Photoinitiators(PIs), as the key substances for photopolymerized antibacterial film(PAF), affect the cure rate and color of PAF. Herein, two enone dyes were designed and synthesized by a facile approach. Among the can...Photoinitiators(PIs), as the key substances for photopolymerized antibacterial film(PAF), affect the cure rate and color of PAF. Herein, two enone dyes were designed and synthesized by a facile approach. Among the candidates, BDO1 has demonstrated the ability to initiate polymerization of acrylate monomers as single-component PI with the advantages of low mobility, outstanding photobleaching, excellent cytocompatibility, and suitability for light emitting diode(LED) light sources above 365 nm. Taking BDOs as examples, a novel method based on theoretical calculations aiming to assess the potential of enone molecules as single-component PIs was proposed. Finally, under the initiation of BDO1, tannic acid was photopolymerized to a colorless and transparent antibacterial film with high antibacterial ability, which indicated that BDO1 was expected to be used in environmentally friendly PAF.展开更多
In this work,semirigid linkers of the alkyl-thiophene-alkyl structure are developed to construct double-cable polymers.Three alkyl units,propyl(C3H6),hexyl(C6H12),and dodecyl(C12H24),are applied as semirigid linkers,y...In this work,semirigid linkers of the alkyl-thiophene-alkyl structure are developed to construct double-cable polymers.Three alkyl units,propyl(C3H6),hexyl(C6H12),and dodecyl(C12H24),are applied as semirigid linkers,yielding three double-cable polymers:PBC6-T,PBC12-T,and PBC24-T,respectively.PBC12-T which uses C6H12-thiophene-C6H12 linkers is found to exhibit the best device efficiency of 5.56%,while PBC6-T and PBC24-T with shorter or longer linkers yield device efficiencies of only 2.65%and 1.09%in single-component organic solar cells(SCOSCs).Further studies reveal that PBC12-T exhibits higher crystallinity and improved charge transport,resulting in better efficiencies.Our work provides an approach to construct double-cable conjugated polymers with long alkyl linkers,and it shows the importance of the linker length for the photovoltaic performance of SCOSCs.展开更多
The photovoltaic properties of double-cable conjugated polymers are significantly influenced by the length of the alkyl linkers that connect donor backbones and acceptor side units. In this study, a series of 2-(3-oxo...The photovoltaic properties of double-cable conjugated polymers are significantly influenced by the length of the alkyl linkers that connect donor backbones and acceptor side units. In this study, a series of 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile(IC)-based double-cable polymers with alkyl linkers ranging from C_8H_(16)to C_(16)H_(32)(Px, x = 8, 10, 12, 14, 16) were synthesized for single-component organic solar cells(SCOSCs). Among these, the linker length x = 12(P12) is found to optimize the power conversion efficiencies(PCEs) in SCOSCs. Specifically, PCEs increase from P8 to P12 and then decline from P12to P16. Detailed investigations of optical absorption, charge transport, and morphology provide insights into the underlying factors contributing to these PCE variations. The findings indicate that the exceptional photovoltaic properties observed in P12 can be attributed to three key factors: A delicate balance between enhanced charge separation facilitated by the increased spacer length and reduced crystallinity resulting from longer spacers, higher charge mobilities, and well-balanced hole/electron transport characteristics. This study highlights the critical role of linker length in determining the photovoltaic properties of double-cable conjugated polymer-based SCOSCs and offers valuable guidance for the design of novel double-cable conjugated polymers.展开更多
Liquid-filled containers(LFC)are widely used to store and transport petroleum,chemical reagents,and other resources.As an important target of military strikes and terrorist bombings,LFC are vulnerable to blast waves a...Liquid-filled containers(LFC)are widely used to store and transport petroleum,chemical reagents,and other resources.As an important target of military strikes and terrorist bombings,LFC are vulnerable to blast waves and fragments.To explore the protective effect of polyurea elastomer on LFC,the damage characteristics of polyurea coated liquid-filled container(PLFC)under the combined loading of blast shock wave and fragments were studied experimentally.The microstructure of the polyurea layer was observed by scanning electron microscopy,and the fracture and self-healing phenomena were analyzed.The simulation approach was used to explain the combined blast-and fragments-induced on the PLFC in detail.Finally,the effects of shock wave and fragment alone and in combination on the damage of PLFC were comprehensively compared.Results showed that the polyurea reduces the perforation rate of the fragment to the LFC,and the self-healing phenomenon could also reduce the liquid loss rate inside the container.The polyurea reduces the degree of depression in the center of the LFC,resulting in a decrease in the distance between adjacent fragments penetrating the LFC,and an increase in the probability of transfixion and fracture between holes.Under the close-in blast,the detonation shock wave reached the LFC before the fragment.Polyurea does not all have an enhanced effect on the protection of LFC.The presence of internal water enhances the anti-blast performance of the container,and the hydrodynamic ram(HRAM)formed by the fragment impacting the water aggravated the plastic deformation of the container.The combined action has an enhancement effect on the deformation of the LFC.The depth of the container depression was 27%higher than that of the blast shock wave alone;thus,it cannot be simply summarized as linear superposition.展开更多
Fluorescent polyurea-carbon dots(PU-CD) were successfully achieved through a co-pyrolysis technique, combining polyurea(PU) with carboxyl-containing carbon dots(PCD) at a temperature of 220 ℃. The PU was fabricated v...Fluorescent polyurea-carbon dots(PU-CD) were successfully achieved through a co-pyrolysis technique, combining polyurea(PU) with carboxyl-containing carbon dots(PCD) at a temperature of 220 ℃. The PU was fabricated via a simple precipitation polymerization process using toluene disocyanate in a water/acetone binary solvent system. PCD was generated by thermal treatment of poly(ethylene glycol)(PEG) at the same elevated temperature. To elucidate the structural characteristics of PU-CD, as well as its precursor components PU and PCD, a comprehensive suite of analytical techniques was employed, including transmission electron microscopy(TEM), Fourier transform infrared spectroscopy(FTIR), nuclear magnetic resonance(NMR), dynamic light scattering(DLS) and X-ray photoelectron spectroscopy(XPS). These analyses confirmed the formation of amide bonds resulting from the reaction between the terminal amines of PU and the carboxyl groups of PCD. An in-depth comparison of the fluorescence properties of PU-CD revealed marked enhancements in fluorescence intensity when contrasted with PU, PEG, and the individual PCD. The research explored the impact of various factors such as concentration, pH in aqueous solutions, and solvent type on the fluorescence emission of these materials, providing valuable insights into their emission mechanisms. It was particularly noteworthy that both PCD and PU-CD exhibited a confined-domain crosslink-enhanced emission effect. Utilizing the aqueous dispersion of PU-CD as a fluorescent probe,the detection of doxycycline(DOX), a long-acting, broad-spectrum, semi-synthetic tetracycline antibiotic, was achieved with a detection limit of 2.9×10^(-7)mol/L. This study introduces a simple, green, and cost-effective fluorescent probe for the detection of DOX, which has significant potential for application in the realms of analytical chemistry and food safety monitoring in the future.展开更多
The viscosity-time curve of a single-component polyurethane(PU)was examined to determine the mixing and compacting temperatures of its mixture and investigate the curing and mechanical properties of single-component P...The viscosity-time curve of a single-component polyurethane(PU)was examined to determine the mixing and compacting temperatures of its mixture and investigate the curing and mechanical properties of single-component PU porous elastic mixture(PPEM).The curing properties of the single-component PU and PPEM were studied with Fourier transform infrared spectroscopy(FTIR)and Marshall test.The mechanical properties of PPEM were explored via the following tests:rutting test,3-point bending test,soaked Marshall stability test,freeze-thaw splitting test,and Cantabro test.The effects of a water bath on the stability of aggregate-PU/asphalt mortar-aggregate systems were evaluated through a pull-out test and a shear test.The results show that the recommended mixing temperatures of toluene diisocyanate and methylene diphenyl diisocyanate range from 75 to 80℃and from 64 to 68℃,respectively.Room temperature(25℃)can be adopted as the compacting temperature of PPEM.PPEM can be fully cured in 4 d.Nevertheless,the water sprinkle method can obviously shorten the full curing time of PPEM.PPEM exhibites good resistance to rutting,brittle cracking,and raveling.The adhesive and shear strength of aggregate-PU/asphalt mortar-aggregate systems are negatively related to water bath duration.展开更多
A new method of synthesizing single-component molecular conductor [Ni(dmit)2] by the reaction 2(Me4N)[Ni(dmit)2]2 [Ni(dmit)2] + (Me4N)[Ni(dmit)2] is reported. [Ni(dmit)2] exhibits a semiconductive behavior above 167...A new method of synthesizing single-component molecular conductor [Ni(dmit)2] by the reaction 2(Me4N)[Ni(dmit)2]2 [Ni(dmit)2] + (Me4N)[Ni(dmit)2] is reported. [Ni(dmit)2] exhibits a semiconductive behavior above 167 K, while from 167 K down to the measuring limit of 60 K, it exhibits metallic conductivity.展开更多
Single-component organic solar cells(SCOSCs)with high stability and simplified fabrication process are supposed to accelerate the commercialization of organic photovoltaics.However,the types of photo-active materials ...Single-component organic solar cells(SCOSCs)with high stability and simplified fabrication process are supposed to accelerate the commercialization of organic photovoltaics.However,the types of photo-active materials and photovoltaic performance of SCOSCs are still far lagging behind the bulk-heterojunction type organic solar cells(BHJ OSCs).It is still an arduous task to introduce new photo-active materials into SCOSCs,aiming to improve the efficiencies of SCOSCs.One feasible way is to construct double-cable polymers with new structures and tune conformation,morphology and mobility for the improvement in power conversion efficiencies(PCEs).Hence,in this work,we constructed a new double-cable polymer PBTT-BPTI by introducing fused core 5,7-dibromo-2,3-bis(2-ethylhexyl)benzo[1,2-b:4,5-c’]dithiophene-4,8-dione(TTDO)into the main backbone and benzo[ghi]-perylene triimide(BPTI)unit into the side chain.Both of the two units show strong electron-withdrawing property,which are expected to broaden absorption spectra and enhance intermolecular interaction.The double-cable polymer exhibited a broad absorption in the range of 300-700 nm with an optical band gap(E_(g))of 1.79 eV.The PCE of PBTT-BPTI-based SCOSCs was 2.15%,which may be limited by the unconstructed efficient electron transporting channels.展开更多
In this work,the“functionalization-polymerization”(FP)method has been used to construct fullerene-contained double-cable conjugated polymers with“donor-acceptor”backbones.It was realized via synthesizing a fullere...In this work,the“functionalization-polymerization”(FP)method has been used to construct fullerene-contained double-cable conjugated polymers with“donor-acceptor”backbones.It was realized via synthesizing a fullerene-contained monomer and performing Stille polymerization.With this method,a series of double-cable conjugated polymers with different fullerene contents were developed and applied into single-component organic solar cells.The power conversion efficiencies(PCEs)based on these polymers increased from 0.71%to 1.71%with the enhanced fullerene contents.The relatively low PCEs might be originated from the poor microstructure in these polymers.These new conjugated polymers with molecular heterojunction would show potential application in organic electronic devices.展开更多
Cavitation,corrosion,and fouling are critical factors that significantly impact the performance of power components in large cargo ships.To address these issues,a composite coating called epoxy-modified polyurea(PUE-F...Cavitation,corrosion,and fouling are critical factors that significantly impact the performance of power components in large cargo ships.To address these issues,a composite coating called epoxy-modified polyurea(PUE-FD)has been developed with reproducible self-healing properties.The incorporation of functionally reduced graphene oxide(FrGO)with multiple hydrogen bonds in the coating led to a notable increase of 5.6 MPa in the tensile strength of PUE-FD.This enhancement was accompanied by excellent resistance to cavitation,as evidenced by a mere 2.8 mg mass loss after 60 h of continuous cavitation.Furthermore,the inclusion of FrGO exhibited an exceptional barrier effect,providing PUE-FD with superior corrosion protection.The|Z|_(0.01) Hz value of PUE-FD was 9.01×10^(9) Ωcm^(2) after 15 days of immersion in 3.5 wt%NaCl solution.Additionally,the synergistic effect of 2-octyl-4,5-dichloroisothiazolinone(DCOIT)and FrGO resulted in remarkable antifouling performance,with a bacterial removal rate exceeding 99.4%and a microalgae removal rate of up to nearly 100%for PUE-FD.PUE-FD also demonstrated remarkable photothermal self-healing ability,achieving a self-healing efficiency of 89%within just 60 s of nearinfrared irradiation.Moreover,the presence of hydrogen bonds in FrGO contributes to the excellent adhesion properties of PUE-FD,resulting in adhesion strengths of more than 10 MPa on copper,stainless steel,and aluminum surfaces.This work presents new inspirations for the preparation of multifunctional coatings with anti-cavitation,anticorrosion,antifouling,and self-healing properties.展开更多
In recent years,explosion shock wave has been considered as a signature injury of the current military conflicts.Although strong shock wave is lethal to the human body,weak shock wave can cause many more lasting conse...In recent years,explosion shock wave has been considered as a signature injury of the current military conflicts.Although strong shock wave is lethal to the human body,weak shock wave can cause many more lasting consequences.To investigate the protection ability and characteristics of flexible materials and structures under weak shock wave loading,the blast wave produced by TNT explosive is loaded on the polyurethane foam with the density of 200.0 kg/m3(F-200)and 400.0 kg/m3(F-400),polyurea with the density of 1100.0 kg/m^(3)(P-1100)and structures composed of the two materials,which are intended for individual protection.Experimental results indicate that the shock wave is attenuated to weak pressure disturbance after interacting with the flexible materials which are not damaged.The shock wave protective capability of single-layer materials is dependent on their thickness,density and microscopic characteristics.The overpressure,maximum pressure rise rate and impulse of transmitted wave decrease exponentially with increase in sample thickness.For the same thickness,F-400 provides better protective capability than F-200 while P-1100 shows the best protective capability among the three materials.In this study,as the materials are not destroyed,F-200 with a thickness more than10.0 mm,F-400 with a thickness more than 4.0 mm,and P-1100 with a thickness more than 1.0 mm can attenuate the overpressure amplitude more than 90.0%.Further,multi-layer flexible composites are designed.Different layer layouts of designed structures and layer thickness of the single-layer materials can affect the protective performance.Within the research range,the structure in which polyurea is placed on the impact side shows the optimal shock wave protective performance,and the thicknesses of polyurea and polyurethane foam are 1.0 mm and 4.0 mm respectively.The overpressure attenuation rate reached maximum value of 93.3%and impulse attenuation capacity of this structure are better than those of single-layer polyurea and polyurethane foam with higher areal density.展开更多
The recently emerged double-cable conjugated polymers have come into focus due to their significantly improved power conversion efficiencies (PCEs) in single-component organic solar cells (SCOSCs). In this work, the e...The recently emerged double-cable conjugated polymers have come into focus due to their significantly improved power conversion efficiencies (PCEs) in single-component organic solar cells (SCOSCs). In this work, the effect of chlorination in double-cable conjugated polymers with linear benzodithiophene backbone and pendant perylene bisimide on the photovoltaic performance in SCOSCs has been studied. After introducing chlorine atoms into conjugated side chains, the highest occupied molecular orbital level of the conjugated polymers is down-shifted, thus resulting in a higher open-circuit voltage. As a result, the chlorinated double-cable conjugated polymer exhibits improved photovoltaic performance from 3.46% to 3.57%.展开更多
The use of CO_(2) as monomer to synthesize polymer materials is an important and potential applications topic from the viewpoint of green and sustainable chemistry.A new kind of CO_(2)-based polyurea(PUa)was synthesiz...The use of CO_(2) as monomer to synthesize polymer materials is an important and potential applications topic from the viewpoint of green and sustainable chemistry.A new kind of CO_(2)-based polyurea(PUa)was synthesized by polycondensation of CO_(2) with 4,7,10-trioxa-1,13-tridecanediamine and tris(2-aminoethyl)amine(TAEA).TAEA was used as cross-link reagent.The mechanical properties of PUa were significantly improved by inserted the crosslink agent of TAEA.The formed slight cross-linked PUa exhibited excellent mechanical properties with tensile strength of 26.8 MPa,elongation at break of 34%and Young’s modulus of 351 MPa.Moreover,it could be remolded for 3 times without obvious change in the mechanical properties,which are ascribed to the hydrogen bonding interaction among the main chains and the slight cross-linked structure.In addition,the synthesized CO_(2)-based PUa is of outstanding thermal performance with an initial decomposition temperature above 300℃,besides it is tolerance for a variety of organic solvents.展开更多
To study the anti-explosion protection effect of polyurea coating on reinforced concrete box girder,two segmental girder specimens were made at a scale of 1:3,numbered as G(without polyurea coating)and PCG(with polyur...To study the anti-explosion protection effect of polyurea coating on reinforced concrete box girder,two segmental girder specimens were made at a scale of 1:3,numbered as G(without polyurea coating)and PCG(with polyurea coating).The failure characteristics and dynamic responses of the specimens were compared through conducting explosion tests.The reliability of the numerical simulation using LS-DYNA software was verified by the test results.The effects of different scaled distances,reinforcement ratios,concrete strengths,coating thicknesses and ranges of polyurea were studied.The results show that the polyurea coating can effectively enhance the anti-explosion performance of the girder.The top plate of middle chamber in specimen G forms an elliptical penetrating hole,while that in specimen PCG only shows a very slight local dent.The peak vertical displacement and residual displacement of PCG decrease by 74.8% and 73.7%,respectively,compared with those of specimen G.For the TNT explosion with small equivalent,the polyurea coating has a more significant protective effect on reducing the size of fracture.With the increase of TNT equivalent,the protective effect of polyurea on reducing girder displacement becomes more significant.The optimal reinforcement ratio,concrete strength,thickness and range of polyurea coating were also drawn.展开更多
By using 6,6-((sulfonylbis(4,1-phenylene)bis(azanediyl))bis(thiophen-2-ylm-ethylene))bis6H-di-benzo[c,e][1,2]oxaphosphinine 6-oxide(DOPO-N)as phosphorus-nitrogen flame retardant,the polyurea(PUA)with flame retardant p...By using 6,6-((sulfonylbis(4,1-phenylene)bis(azanediyl))bis(thiophen-2-ylm-ethylene))bis6H-di-benzo[c,e][1,2]oxaphosphinine 6-oxide(DOPO-N)as phosphorus-nitrogen flame retardant,the polyurea(PUA)with flame retardant properties(PUA/DOPO-N)was prepared.In addition,organically modified montmorillonite(OMMT)and magnesium hydroxide(MH)were used as co-effectors respectively,and the flame retardant PUA(PUA/DOPO-N/OMMT and PUA/DOPO-N/MH)were also prepared.Thermal properties,flame retardant properties,flame retardant mechanism and mechanical properties of PUA/DOPO-N,PUA/DOPO-N/OMMT and PUA/DOPO-N/MH were investigated by thermogravimetric(TG)analysis,limiting oxygen index(LOI),UL 94,cone calorimeter test,scanning electron microscopy(SEM),and tensile test.The results show that the LOI value of PUA/20%DOPO-N,PUA/18%DOPO-N/2%OMMT and PUA/15%DOPO-N/5%MH are 27.1%,27.7%,and 28.3%,respectively,and UL 94 V-0 rating is attained.Compared with PUA,the peak heat release rate(pk-HRR),total heat release(THR)and average effective heat combustion(av-EHC)of PUA/20%DOPO-N,PUA/18%DOPO-N/2%OMMT and PUA/15%DOPO-N/5%MH decrease significantly.SEM results indicate that the residual chars of PUA/20%DOPO-N,PUA/18%DOPO-N/2%OMMT and PUA/15%DOPO-N/5%MH are completer and more compact.The complex of DOPO-N/OMMT and DOPO-N/MH have synergistic flame retardancy.The mechanical properties of PUA can be improved by the addition of DOPO-N,DOPO-N/OMMT and DOPO-N/MH,respectively.The insulation performance test shows that the volume resistivity of PUA/20%DOPO-N is 6.25×10^(16)Ω.cm.Furthermore,by using modified boron nitride(MBN)as heat dissipating material,the complex of PUA/MBN was prepared,and the thermal conductivity of PUA/MBN was investigated.The thermal conductivity of PUA/8%MBN complex coating at room temperature is 0.166 W/(M·K),which is a 163%improvement over pure PUA.展开更多
[Objectives] This study was conducted to develop a polyurea elastomer which can be sprayed on the surface of expanded polystyrene (EPS) floating balls, so as to improve the surface strength and service life of the flo...[Objectives] This study was conducted to develop a polyurea elastomer which can be sprayed on the surface of expanded polystyrene (EPS) floating balls, so as to improve the surface strength and service life of the floating balls. [Methods] The effects of the types and amounts of isocyanate, chain extenders and polyether polyols on the gelation rate, adhesion and wear resistance of polyurea elastomer were investigated, and it was finally determined the preparation process of polyurea elastomer using liquid isophorone diisocyanate (IPDI) and amino-terminated polyether (D2000) as the main raw materials, dimethylthiotoluene diamine (E300) as the chain extender and silica as the wear resistance modifier through two-step solution polymerization of prepolymerization and chain extension. [Results] The physical properties and chemical resistance tests of spray polyurea elastomer showed that it had good physical properties and acid and alkali resistance, and could meet the requirements of spraying and protection of EPS floating ball surface in marine environment. [Conclusions] Polyurea elastomer coating can improve the aging resistance, wear resistance and acid and alkali resistance of EPS floating balls, and prevent them from being fragile and floating randomly to form marine floating garbage which results in "white pollution".展开更多
基金financially supported by National Natural Science Foundation of China (Nos. 21925802, 22338005)Liaoning Binhai Laboratory (No. LBLB-2023–03)the Fundamental Research Funds for the Central Universities (No. DUT22LAB601)。
文摘Photoinitiators(PIs), as the key substances for photopolymerized antibacterial film(PAF), affect the cure rate and color of PAF. Herein, two enone dyes were designed and synthesized by a facile approach. Among the candidates, BDO1 has demonstrated the ability to initiate polymerization of acrylate monomers as single-component PI with the advantages of low mobility, outstanding photobleaching, excellent cytocompatibility, and suitability for light emitting diode(LED) light sources above 365 nm. Taking BDOs as examples, a novel method based on theoretical calculations aiming to assess the potential of enone molecules as single-component PIs was proposed. Finally, under the initiation of BDO1, tannic acid was photopolymerized to a colorless and transparent antibacterial film with high antibacterial ability, which indicated that BDO1 was expected to be used in environmentally friendly PAF.
基金the Beijing Natural Science Foundation(No.JQ21006)the Ministry of Science and Technology(No.2018YFA0208504)+3 种基金the National Natural Science Foundation(Nos.92163128,52073016,21905018)of Chinathe Fundamental Research Funds for the Central Universities(Nos.buctrc201828,XK1802-2)Open Project of State Key Laboratory of Organic-Inorganic Composites(No.oic-202201006)Open Project of State Key Laboratory of Supramolecular Structure and Materials(No.sklssm202209).
文摘In this work,semirigid linkers of the alkyl-thiophene-alkyl structure are developed to construct double-cable polymers.Three alkyl units,propyl(C3H6),hexyl(C6H12),and dodecyl(C12H24),are applied as semirigid linkers,yielding three double-cable polymers:PBC6-T,PBC12-T,and PBC24-T,respectively.PBC12-T which uses C6H12-thiophene-C6H12 linkers is found to exhibit the best device efficiency of 5.56%,while PBC6-T and PBC24-T with shorter or longer linkers yield device efficiencies of only 2.65%and 1.09%in single-component organic solar cells(SCOSCs).Further studies reveal that PBC12-T exhibits higher crystallinity and improved charge transport,resulting in better efficiencies.Our work provides an approach to construct double-cable conjugated polymers with long alkyl linkers,and it shows the importance of the linker length for the photovoltaic performance of SCOSCs.
基金jointly supported by the Beijing Natural Science Foundation (Nos.2212045 and JQ21006)the National Natural Science Foundation of China (Nos.21905158, 52073016 and 92163128)+2 种基金further supported by the Fundamental Research Funds for the Central Universities (Nos.buctrc202111, buctrc201828, and XK1802-2)the Opening Foundation of State Key Laboratory of Organic-Inorganic Composites of Beijing University of Chemical Technology (No.oic-202201006)Jiangxi Provincial Department of Science and Technology (Nos.20202ACBL213004, 20212BCJ23035, jxsq2019102004)。
文摘The photovoltaic properties of double-cable conjugated polymers are significantly influenced by the length of the alkyl linkers that connect donor backbones and acceptor side units. In this study, a series of 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile(IC)-based double-cable polymers with alkyl linkers ranging from C_8H_(16)to C_(16)H_(32)(Px, x = 8, 10, 12, 14, 16) were synthesized for single-component organic solar cells(SCOSCs). Among these, the linker length x = 12(P12) is found to optimize the power conversion efficiencies(PCEs) in SCOSCs. Specifically, PCEs increase from P8 to P12 and then decline from P12to P16. Detailed investigations of optical absorption, charge transport, and morphology provide insights into the underlying factors contributing to these PCE variations. The findings indicate that the exceptional photovoltaic properties observed in P12 can be attributed to three key factors: A delicate balance between enhanced charge separation facilitated by the increased spacer length and reduced crystallinity resulting from longer spacers, higher charge mobilities, and well-balanced hole/electron transport characteristics. This study highlights the critical role of linker length in determining the photovoltaic properties of double-cable conjugated polymer-based SCOSCs and offers valuable guidance for the design of novel double-cable conjugated polymers.
基金supported by the National Natural Science Foundation of China(Grant Nos.12102480,52278543 and 51978660)Natural Science Foundation of Jiangsu Province(Grant No.BK20231489)。
文摘Liquid-filled containers(LFC)are widely used to store and transport petroleum,chemical reagents,and other resources.As an important target of military strikes and terrorist bombings,LFC are vulnerable to blast waves and fragments.To explore the protective effect of polyurea elastomer on LFC,the damage characteristics of polyurea coated liquid-filled container(PLFC)under the combined loading of blast shock wave and fragments were studied experimentally.The microstructure of the polyurea layer was observed by scanning electron microscopy,and the fracture and self-healing phenomena were analyzed.The simulation approach was used to explain the combined blast-and fragments-induced on the PLFC in detail.Finally,the effects of shock wave and fragment alone and in combination on the damage of PLFC were comprehensively compared.Results showed that the polyurea reduces the perforation rate of the fragment to the LFC,and the self-healing phenomenon could also reduce the liquid loss rate inside the container.The polyurea reduces the degree of depression in the center of the LFC,resulting in a decrease in the distance between adjacent fragments penetrating the LFC,and an increase in the probability of transfixion and fracture between holes.Under the close-in blast,the detonation shock wave reached the LFC before the fragment.Polyurea does not all have an enhanced effect on the protection of LFC.The presence of internal water enhances the anti-blast performance of the container,and the hydrodynamic ram(HRAM)formed by the fragment impacting the water aggravated the plastic deformation of the container.The combined action has an enhancement effect on the deformation of the LFC.The depth of the container depression was 27%higher than that of the blast shock wave alone;thus,it cannot be simply summarized as linear superposition.
基金supported by the Nature Science Foundation of Shandong Province,China(Nos.ZR2022MB051 , ZR2021MB112)Science and Technology Bureau of Jinan City(No.2021GXRC105),Postdoctoral Science Foundation of China(No.2022M712343)+1 种基金Jinan City University Integration Development Strategy Project(No.JNSX2024030)a key laboratory of special functional aggregates of the Ministry of Education,Shandong University(No.JT-2023-02).
文摘Fluorescent polyurea-carbon dots(PU-CD) were successfully achieved through a co-pyrolysis technique, combining polyurea(PU) with carboxyl-containing carbon dots(PCD) at a temperature of 220 ℃. The PU was fabricated via a simple precipitation polymerization process using toluene disocyanate in a water/acetone binary solvent system. PCD was generated by thermal treatment of poly(ethylene glycol)(PEG) at the same elevated temperature. To elucidate the structural characteristics of PU-CD, as well as its precursor components PU and PCD, a comprehensive suite of analytical techniques was employed, including transmission electron microscopy(TEM), Fourier transform infrared spectroscopy(FTIR), nuclear magnetic resonance(NMR), dynamic light scattering(DLS) and X-ray photoelectron spectroscopy(XPS). These analyses confirmed the formation of amide bonds resulting from the reaction between the terminal amines of PU and the carboxyl groups of PCD. An in-depth comparison of the fluorescence properties of PU-CD revealed marked enhancements in fluorescence intensity when contrasted with PU, PEG, and the individual PCD. The research explored the impact of various factors such as concentration, pH in aqueous solutions, and solvent type on the fluorescence emission of these materials, providing valuable insights into their emission mechanisms. It was particularly noteworthy that both PCD and PU-CD exhibited a confined-domain crosslink-enhanced emission effect. Utilizing the aqueous dispersion of PU-CD as a fluorescent probe,the detection of doxycycline(DOX), a long-acting, broad-spectrum, semi-synthetic tetracycline antibiotic, was achieved with a detection limit of 2.9×10^(-7)mol/L. This study introduces a simple, green, and cost-effective fluorescent probe for the detection of DOX, which has significant potential for application in the realms of analytical chemistry and food safety monitoring in the future.
基金The Fundamental Research Funds for the Central Research Institute (No. 2020-9054)。
文摘The viscosity-time curve of a single-component polyurethane(PU)was examined to determine the mixing and compacting temperatures of its mixture and investigate the curing and mechanical properties of single-component PU porous elastic mixture(PPEM).The curing properties of the single-component PU and PPEM were studied with Fourier transform infrared spectroscopy(FTIR)and Marshall test.The mechanical properties of PPEM were explored via the following tests:rutting test,3-point bending test,soaked Marshall stability test,freeze-thaw splitting test,and Cantabro test.The effects of a water bath on the stability of aggregate-PU/asphalt mortar-aggregate systems were evaluated through a pull-out test and a shear test.The results show that the recommended mixing temperatures of toluene diisocyanate and methylene diphenyl diisocyanate range from 75 to 80℃and from 64 to 68℃,respectively.Room temperature(25℃)can be adopted as the compacting temperature of PPEM.PPEM can be fully cured in 4 d.Nevertheless,the water sprinkle method can obviously shorten the full curing time of PPEM.PPEM exhibites good resistance to rutting,brittle cracking,and raveling.The adhesive and shear strength of aggregate-PU/asphalt mortar-aggregate systems are negatively related to water bath duration.
基金supported by the National Natural Science Foundation of China(No.20172034)Foundation for Univemity Key Teacher by Ministry of Educationthe grant for the State Key Program of China.
文摘A new method of synthesizing single-component molecular conductor [Ni(dmit)2] by the reaction 2(Me4N)[Ni(dmit)2]2 [Ni(dmit)2] + (Me4N)[Ni(dmit)2] is reported. [Ni(dmit)2] exhibits a semiconductive behavior above 167 K, while from 167 K down to the measuring limit of 60 K, it exhibits metallic conductivity.
基金jointly supported by National Key R&D Program of China(Nos.2018YFA0208504,2017YFA0204702)National Natural Science Foundation of China(Nos.51773207,21574138,21905018)+2 种基金Natural Science Foundation of Hebei Province(No.B2020201032)further supported by the Fundamental Research Funds for the Central Universities(No.XK1802-2)Open Project of State Key Laboratory of Supramolecular Structure and Materials(No.sklssm202043)。
文摘Single-component organic solar cells(SCOSCs)with high stability and simplified fabrication process are supposed to accelerate the commercialization of organic photovoltaics.However,the types of photo-active materials and photovoltaic performance of SCOSCs are still far lagging behind the bulk-heterojunction type organic solar cells(BHJ OSCs).It is still an arduous task to introduce new photo-active materials into SCOSCs,aiming to improve the efficiencies of SCOSCs.One feasible way is to construct double-cable polymers with new structures and tune conformation,morphology and mobility for the improvement in power conversion efficiencies(PCEs).Hence,in this work,we constructed a new double-cable polymer PBTT-BPTI by introducing fused core 5,7-dibromo-2,3-bis(2-ethylhexyl)benzo[1,2-b:4,5-c’]dithiophene-4,8-dione(TTDO)into the main backbone and benzo[ghi]-perylene triimide(BPTI)unit into the side chain.Both of the two units show strong electron-withdrawing property,which are expected to broaden absorption spectra and enhance intermolecular interaction.The double-cable polymer exhibited a broad absorption in the range of 300-700 nm with an optical band gap(E_(g))of 1.79 eV.The PCE of PBTT-BPTI-based SCOSCs was 2.15%,which may be limited by the unconstructed efficient electron transporting channels.
基金This study was financially supported by Beijing Natural Science Foundation of China.(No.JQ21006)the National Natural Science Foundation of China(Nos.92163128,52073016,51773207,21905018 and 21905158)of China+2 种基金This work was further financially supported by the Fundamental Research Funds for the Central Universities(Nos.buctrc201828 and XK1802-2)the opening Foundation of State Key Laboratory of Organic-Inorganic Composites,Beijing University of Chemical Technology(No.oic-202201006)Jiangxi Provincial Department of Science and Technology(No.20192ACB20009).
文摘In this work,the“functionalization-polymerization”(FP)method has been used to construct fullerene-contained double-cable conjugated polymers with“donor-acceptor”backbones.It was realized via synthesizing a fullerene-contained monomer and performing Stille polymerization.With this method,a series of double-cable conjugated polymers with different fullerene contents were developed and applied into single-component organic solar cells.The power conversion efficiencies(PCEs)based on these polymers increased from 0.71%to 1.71%with the enhanced fullerene contents.The relatively low PCEs might be originated from the poor microstructure in these polymers.These new conjugated polymers with molecular heterojunction would show potential application in organic electronic devices.
基金This work was funded by the National Natural Science Founda-tion of China(Grant No.52375286)the Major Science and Tech-nology Special Projects of Jilin Province(No.YDZI202203CGZH035)the Young and Middle aged Technology Innovation LeadingIa-lents,the Team Projects of Science and Technology Development Plan of Jilin Province(No.20230508041RC).
文摘Cavitation,corrosion,and fouling are critical factors that significantly impact the performance of power components in large cargo ships.To address these issues,a composite coating called epoxy-modified polyurea(PUE-FD)has been developed with reproducible self-healing properties.The incorporation of functionally reduced graphene oxide(FrGO)with multiple hydrogen bonds in the coating led to a notable increase of 5.6 MPa in the tensile strength of PUE-FD.This enhancement was accompanied by excellent resistance to cavitation,as evidenced by a mere 2.8 mg mass loss after 60 h of continuous cavitation.Furthermore,the inclusion of FrGO exhibited an exceptional barrier effect,providing PUE-FD with superior corrosion protection.The|Z|_(0.01) Hz value of PUE-FD was 9.01×10^(9) Ωcm^(2) after 15 days of immersion in 3.5 wt%NaCl solution.Additionally,the synergistic effect of 2-octyl-4,5-dichloroisothiazolinone(DCOIT)and FrGO resulted in remarkable antifouling performance,with a bacterial removal rate exceeding 99.4%and a microalgae removal rate of up to nearly 100%for PUE-FD.PUE-FD also demonstrated remarkable photothermal self-healing ability,achieving a self-healing efficiency of 89%within just 60 s of nearinfrared irradiation.Moreover,the presence of hydrogen bonds in FrGO contributes to the excellent adhesion properties of PUE-FD,resulting in adhesion strengths of more than 10 MPa on copper,stainless steel,and aluminum surfaces.This work presents new inspirations for the preparation of multifunctional coatings with anti-cavitation,anticorrosion,antifouling,and self-healing properties.
基金supported by the National Natural Science Foundation of China(Grant Nos.12221002,12102233)。
文摘In recent years,explosion shock wave has been considered as a signature injury of the current military conflicts.Although strong shock wave is lethal to the human body,weak shock wave can cause many more lasting consequences.To investigate the protection ability and characteristics of flexible materials and structures under weak shock wave loading,the blast wave produced by TNT explosive is loaded on the polyurethane foam with the density of 200.0 kg/m3(F-200)and 400.0 kg/m3(F-400),polyurea with the density of 1100.0 kg/m^(3)(P-1100)and structures composed of the two materials,which are intended for individual protection.Experimental results indicate that the shock wave is attenuated to weak pressure disturbance after interacting with the flexible materials which are not damaged.The shock wave protective capability of single-layer materials is dependent on their thickness,density and microscopic characteristics.The overpressure,maximum pressure rise rate and impulse of transmitted wave decrease exponentially with increase in sample thickness.For the same thickness,F-400 provides better protective capability than F-200 while P-1100 shows the best protective capability among the three materials.In this study,as the materials are not destroyed,F-200 with a thickness more than10.0 mm,F-400 with a thickness more than 4.0 mm,and P-1100 with a thickness more than 1.0 mm can attenuate the overpressure amplitude more than 90.0%.Further,multi-layer flexible composites are designed.Different layer layouts of designed structures and layer thickness of the single-layer materials can affect the protective performance.Within the research range,the structure in which polyurea is placed on the impact side shows the optimal shock wave protective performance,and the thicknesses of polyurea and polyurethane foam are 1.0 mm and 4.0 mm respectively.The overpressure attenuation rate reached maximum value of 93.3%and impulse attenuation capacity of this structure are better than those of single-layer polyurea and polyurethane foam with higher areal density.
基金the National Natural Science Foundation of China(Nos.51973169,51703172 and 52073016)the Open Project Program of Wuhan National Laboratory for Optoelectronics(No.2020WNLOKF015)the science foundation of Wuhan Institute of Technology(No.K202025).
文摘The recently emerged double-cable conjugated polymers have come into focus due to their significantly improved power conversion efficiencies (PCEs) in single-component organic solar cells (SCOSCs). In this work, the effect of chlorination in double-cable conjugated polymers with linear benzodithiophene backbone and pendant perylene bisimide on the photovoltaic performance in SCOSCs has been studied. After introducing chlorine atoms into conjugated side chains, the highest occupied molecular orbital level of the conjugated polymers is down-shifted, thus resulting in a higher open-circuit voltage. As a result, the chlorinated double-cable conjugated polymer exhibits improved photovoltaic performance from 3.46% to 3.57%.
文摘The use of CO_(2) as monomer to synthesize polymer materials is an important and potential applications topic from the viewpoint of green and sustainable chemistry.A new kind of CO_(2)-based polyurea(PUa)was synthesized by polycondensation of CO_(2) with 4,7,10-trioxa-1,13-tridecanediamine and tris(2-aminoethyl)amine(TAEA).TAEA was used as cross-link reagent.The mechanical properties of PUa were significantly improved by inserted the crosslink agent of TAEA.The formed slight cross-linked PUa exhibited excellent mechanical properties with tensile strength of 26.8 MPa,elongation at break of 34%and Young’s modulus of 351 MPa.Moreover,it could be remolded for 3 times without obvious change in the mechanical properties,which are ascribed to the hydrogen bonding interaction among the main chains and the slight cross-linked structure.In addition,the synthesized CO_(2)-based PUa is of outstanding thermal performance with an initial decomposition temperature above 300℃,besides it is tolerance for a variety of organic solvents.
基金the Natural Science Foundation of Jiangsu Province(Grant No.BK20200494)China Postdoctoral Science Foundation(Grant No.2021M701725)+3 种基金Jiangsu Postdoctoral Research Funding Program(Grant No.2021K522C)Fundamental Research Funds for the Central Universities(Grant No.30919011246)National Natural Science Foundation of China(Grant No.52278188)Natural Science Foundation of Jiangsu Province(Grant No.BK20211196)。
文摘To study the anti-explosion protection effect of polyurea coating on reinforced concrete box girder,two segmental girder specimens were made at a scale of 1:3,numbered as G(without polyurea coating)and PCG(with polyurea coating).The failure characteristics and dynamic responses of the specimens were compared through conducting explosion tests.The reliability of the numerical simulation using LS-DYNA software was verified by the test results.The effects of different scaled distances,reinforcement ratios,concrete strengths,coating thicknesses and ranges of polyurea were studied.The results show that the polyurea coating can effectively enhance the anti-explosion performance of the girder.The top plate of middle chamber in specimen G forms an elliptical penetrating hole,while that in specimen PCG only shows a very slight local dent.The peak vertical displacement and residual displacement of PCG decrease by 74.8% and 73.7%,respectively,compared with those of specimen G.For the TNT explosion with small equivalent,the polyurea coating has a more significant protective effect on reducing the size of fracture.With the increase of TNT equivalent,the protective effect of polyurea on reducing girder displacement becomes more significant.The optimal reinforcement ratio,concrete strength,thickness and range of polyurea coating were also drawn.
基金Funded by the Natural Science Foundation of Guangdong(Nos.2014A030313241,2014B090901068,and 2016A010103003)。
文摘By using 6,6-((sulfonylbis(4,1-phenylene)bis(azanediyl))bis(thiophen-2-ylm-ethylene))bis6H-di-benzo[c,e][1,2]oxaphosphinine 6-oxide(DOPO-N)as phosphorus-nitrogen flame retardant,the polyurea(PUA)with flame retardant properties(PUA/DOPO-N)was prepared.In addition,organically modified montmorillonite(OMMT)and magnesium hydroxide(MH)were used as co-effectors respectively,and the flame retardant PUA(PUA/DOPO-N/OMMT and PUA/DOPO-N/MH)were also prepared.Thermal properties,flame retardant properties,flame retardant mechanism and mechanical properties of PUA/DOPO-N,PUA/DOPO-N/OMMT and PUA/DOPO-N/MH were investigated by thermogravimetric(TG)analysis,limiting oxygen index(LOI),UL 94,cone calorimeter test,scanning electron microscopy(SEM),and tensile test.The results show that the LOI value of PUA/20%DOPO-N,PUA/18%DOPO-N/2%OMMT and PUA/15%DOPO-N/5%MH are 27.1%,27.7%,and 28.3%,respectively,and UL 94 V-0 rating is attained.Compared with PUA,the peak heat release rate(pk-HRR),total heat release(THR)and average effective heat combustion(av-EHC)of PUA/20%DOPO-N,PUA/18%DOPO-N/2%OMMT and PUA/15%DOPO-N/5%MH decrease significantly.SEM results indicate that the residual chars of PUA/20%DOPO-N,PUA/18%DOPO-N/2%OMMT and PUA/15%DOPO-N/5%MH are completer and more compact.The complex of DOPO-N/OMMT and DOPO-N/MH have synergistic flame retardancy.The mechanical properties of PUA can be improved by the addition of DOPO-N,DOPO-N/OMMT and DOPO-N/MH,respectively.The insulation performance test shows that the volume resistivity of PUA/20%DOPO-N is 6.25×10^(16)Ω.cm.Furthermore,by using modified boron nitride(MBN)as heat dissipating material,the complex of PUA/MBN was prepared,and the thermal conductivity of PUA/MBN was investigated.The thermal conductivity of PUA/8%MBN complex coating at room temperature is 0.166 W/(M·K),which is a 163%improvement over pure PUA.
基金Supported by Special Project for High-quality Development of Marine Services and Fishery in Fujian Province in 2023(FJHY-YYKJ-2023-1-3)。
文摘[Objectives] This study was conducted to develop a polyurea elastomer which can be sprayed on the surface of expanded polystyrene (EPS) floating balls, so as to improve the surface strength and service life of the floating balls. [Methods] The effects of the types and amounts of isocyanate, chain extenders and polyether polyols on the gelation rate, adhesion and wear resistance of polyurea elastomer were investigated, and it was finally determined the preparation process of polyurea elastomer using liquid isophorone diisocyanate (IPDI) and amino-terminated polyether (D2000) as the main raw materials, dimethylthiotoluene diamine (E300) as the chain extender and silica as the wear resistance modifier through two-step solution polymerization of prepolymerization and chain extension. [Results] The physical properties and chemical resistance tests of spray polyurea elastomer showed that it had good physical properties and acid and alkali resistance, and could meet the requirements of spraying and protection of EPS floating ball surface in marine environment. [Conclusions] Polyurea elastomer coating can improve the aging resistance, wear resistance and acid and alkali resistance of EPS floating balls, and prevent them from being fragile and floating randomly to form marine floating garbage which results in "white pollution".
