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2018 Volume 35 Issue 9
2018, 35(9): 975-975
doi: 10.11944/j.issn.1000-0518.2018.09.180225
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2018, 35(9): 976-976
doi: 10.11944/j.issn.1000-0518.2018.09.180224
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2018, 35(9): 977-983
doi: 10.11944/j.issn.1000-0518.2018.09.180208
Abstract:
Proteomics, as one of the foremost branches of science in the post-genome era, is mainly focused on the expression, translational modification and interaction of proteins in cells, tissues and organs. With the rapid advancement of precision medicine and life science, higher and higher requirements have been put forward for the development of analytical methods for proteomics. Herein, we summarized the new technologies for proteome research since 2013 and prospected the future of new technics and methods for protein research.
Proteomics, as one of the foremost branches of science in the post-genome era, is mainly focused on the expression, translational modification and interaction of proteins in cells, tissues and organs. With the rapid advancement of precision medicine and life science, higher and higher requirements have been put forward for the development of analytical methods for proteomics. Herein, we summarized the new technologies for proteome research since 2013 and prospected the future of new technics and methods for protein research.
2018, 35(9): 984-992
doi: 10.11944/j.issn.1000-0518.2018.09.180172
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Surface-enhanced Raman spectroscopy (SERS) is a fingerprint spectroscopic technique with ultra-high sensitivity. It has been widely used in surface science, material science, biomedicine, drug analysis, food safety inspection, and pollutant detection, as a promising technique for trace analysis. In this paper, we comprehensively reviewed the development and applications of SERS and related techniques, including tip-enhanced Raman spectroscopy (TERS), shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS), and discussed its research frontiers and development directions in the future.
Surface-enhanced Raman spectroscopy (SERS) is a fingerprint spectroscopic technique with ultra-high sensitivity. It has been widely used in surface science, material science, biomedicine, drug analysis, food safety inspection, and pollutant detection, as a promising technique for trace analysis. In this paper, we comprehensively reviewed the development and applications of SERS and related techniques, including tip-enhanced Raman spectroscopy (TERS), shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS), and discussed its research frontiers and development directions in the future.
2018, 35(9): 993-1004
doi: 10.11944/j.issn.1000-0518.2018.09.180202
Abstract:
Thermally activated delayed fluorescence polymers can achieve 100% internal quantum efficiency by utilizing triplet excitons through enhanced reverse intersystem crossing process from the lowest triplet state to singlet state, thereby representing a promising approach toward low-cost and high-effiicnecy light-emitting polymers. Recently, great progress has been made on the material design and device performance of thermally activated delayed fluorescence polymers. This review is aimed to summarize the research progresses on thermally activated delayed fluorescence polymers, with the focus on the molecular design, photophysical characteristic and device performance of mainchain-and sidechain-type thermally activated delayed fluorescence polymers as well as thermally activated delayed fluorescence dendrimers. Finally, the perspectives and the key challenges on developing thermally activated delayed fluorescence polymers are also discussed.
Thermally activated delayed fluorescence polymers can achieve 100% internal quantum efficiency by utilizing triplet excitons through enhanced reverse intersystem crossing process from the lowest triplet state to singlet state, thereby representing a promising approach toward low-cost and high-effiicnecy light-emitting polymers. Recently, great progress has been made on the material design and device performance of thermally activated delayed fluorescence polymers. This review is aimed to summarize the research progresses on thermally activated delayed fluorescence polymers, with the focus on the molecular design, photophysical characteristic and device performance of mainchain-and sidechain-type thermally activated delayed fluorescence polymers as well as thermally activated delayed fluorescence dendrimers. Finally, the perspectives and the key challenges on developing thermally activated delayed fluorescence polymers are also discussed.
2018, 35(9): 1005-1012
doi: 10.11944/j.issn.1000-0518.2018.09.180156
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Based on the vulcanization principle of addition type liquid silicone rubber, the latest research progress on the thermal conductivity, high temperature resistance and adhesive property of addition type liquid silicone rubber is summarized. It has been found that adding a metal nitride thermal conductive filler is a prominent approach to improving the thermal conductivity of addition type liquid silicone rubber; while improving the molecular structure is effective for enhancing the high-temperature resistance of addition type liquid silicone rubber, and blending the adhesion promoters can prominently enhance the performance of addition type liquid silicone rubber. In this paper, the latest application of addition type liquid silicone rubber in many fields is introduced, and it is also mentioned that functionalized addition type liquid silicone rubber, such as 3D personalized printing silicone rubber, human body replacement silicone rubber, and high refraction encapsulated silicone rubber, is the direction for the future development of addition type liquid silicone rubber.
Based on the vulcanization principle of addition type liquid silicone rubber, the latest research progress on the thermal conductivity, high temperature resistance and adhesive property of addition type liquid silicone rubber is summarized. It has been found that adding a metal nitride thermal conductive filler is a prominent approach to improving the thermal conductivity of addition type liquid silicone rubber; while improving the molecular structure is effective for enhancing the high-temperature resistance of addition type liquid silicone rubber, and blending the adhesion promoters can prominently enhance the performance of addition type liquid silicone rubber. In this paper, the latest application of addition type liquid silicone rubber in many fields is introduced, and it is also mentioned that functionalized addition type liquid silicone rubber, such as 3D personalized printing silicone rubber, human body replacement silicone rubber, and high refraction encapsulated silicone rubber, is the direction for the future development of addition type liquid silicone rubber.
2018, 35(9): 1013-1018
doi: 10.11944/j.issn.1000-0518.2018.09.180178
Abstract:
Frustrated Lewis pairs (FLPs) are combinations of bulky Lewis acids and bulky Lewis bases in solution that are deterred to from dative bonds by steric factors. In this particular combination, Lewis acids and Lewis bases failed to be neutralized and quenched, and remained reactive. When small molecules such as H2 are close to them, FLPs can split the chemical bonds of H2 to obtain a cation and an anion. This particular reaction activity shows promising applications of FLPs in catalytic hydrogenation, activation of small molecules, olefin polymerization, ring-opening polymerization and so on. Especially, in olefin polymerization and ring-opening polymerization, FLPs have a strong catalytic activity. In this article, we briefly introduce the development history of FLPs and the application of FLPs in activation of small molecules. In addition, the applications of FLPs in polymer fields are emphatically described.
Frustrated Lewis pairs (FLPs) are combinations of bulky Lewis acids and bulky Lewis bases in solution that are deterred to from dative bonds by steric factors. In this particular combination, Lewis acids and Lewis bases failed to be neutralized and quenched, and remained reactive. When small molecules such as H2 are close to them, FLPs can split the chemical bonds of H2 to obtain a cation and an anion. This particular reaction activity shows promising applications of FLPs in catalytic hydrogenation, activation of small molecules, olefin polymerization, ring-opening polymerization and so on. Especially, in olefin polymerization and ring-opening polymerization, FLPs have a strong catalytic activity. In this article, we briefly introduce the development history of FLPs and the application of FLPs in activation of small molecules. In addition, the applications of FLPs in polymer fields are emphatically described.
2018, 35(9): 1019-1025
doi: 10.11944/j.issn.1000-0518.2018.09.180184
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Organic pollutants in water system are widely viewed as a serious threat to ecologic safety and human health, and it has become a global issue to develop effect technology to control and reduce organic pollutants in water system. Adsorption treatment, based on various porous materials, is believed to be a promising solution to this question. Porous organic polymers (POPs), characterized with high specific surface area, high physical and chemical stability, and easy functionalization, exhibit great potential application in tackling organic pollution of water. In this article, the recent advances were briefly reviewed on the application of POPs in adsorbing organic pollutants such as common organic solvents, pesticides and insecticides, organic dyes in water system.
Organic pollutants in water system are widely viewed as a serious threat to ecologic safety and human health, and it has become a global issue to develop effect technology to control and reduce organic pollutants in water system. Adsorption treatment, based on various porous materials, is believed to be a promising solution to this question. Porous organic polymers (POPs), characterized with high specific surface area, high physical and chemical stability, and easy functionalization, exhibit great potential application in tackling organic pollution of water. In this article, the recent advances were briefly reviewed on the application of POPs in adsorbing organic pollutants such as common organic solvents, pesticides and insecticides, organic dyes in water system.
2018, 35(9): 1026-1036
doi: 10.11944/j.issn.1000-0518.2018.09.180174
Abstract:
Various materials can be encapsulated with polymer to form nanoparticles with complex structures via miniemulsion polymerization. Miniemulsion polymerization has the advantages of convenience, environmental protection, controllable particle size and high stability compared with ordinary emulsion polymerization. Functionalization of nanoparticles can be easily realized by adding functional monomers. At present, miniemulsion polymerization technology has been applied to many fields, such as textile pigment, adhesives, molecular imprinting, magnetic targeting nanoparticles and so on. The applications of miniemulsion polymerization for the synthesis of nanoparticles in recent years are reviewed in this paper.
Various materials can be encapsulated with polymer to form nanoparticles with complex structures via miniemulsion polymerization. Miniemulsion polymerization has the advantages of convenience, environmental protection, controllable particle size and high stability compared with ordinary emulsion polymerization. Functionalization of nanoparticles can be easily realized by adding functional monomers. At present, miniemulsion polymerization technology has been applied to many fields, such as textile pigment, adhesives, molecular imprinting, magnetic targeting nanoparticles and so on. The applications of miniemulsion polymerization for the synthesis of nanoparticles in recent years are reviewed in this paper.
2018, 35(9): 1037-1056
doi: 10.11944/j.issn.1000-0518.2018.09.180173
Abstract:
Donor acceptor (DA) strained ring compounds, such as DA cyclopropanes, are useful synthetic building blocks, which have been applied in the total synthesis of natural products and biologically active molecules. Recent years, we have developed a series of highly effective methods for the preparation of chiral DA cyclopropanes, as well as the enantioselective ring-opening and annulation reactions of DA cyclopropanes with nucleophiles, such as amines, alcohols, nitrones, azomethine imines, enol silyl ethers, indoles and so on, by employing chiral copper or nickel complexes as catalysts. This accounts summarized our studies on the enantioselective cyclopropanation, asymmetric ring-opening/annulation and kinetic resolution of racemic DA cyclopropanes.
Donor acceptor (DA) strained ring compounds, such as DA cyclopropanes, are useful synthetic building blocks, which have been applied in the total synthesis of natural products and biologically active molecules. Recent years, we have developed a series of highly effective methods for the preparation of chiral DA cyclopropanes, as well as the enantioselective ring-opening and annulation reactions of DA cyclopropanes with nucleophiles, such as amines, alcohols, nitrones, azomethine imines, enol silyl ethers, indoles and so on, by employing chiral copper or nickel complexes as catalysts. This accounts summarized our studies on the enantioselective cyclopropanation, asymmetric ring-opening/annulation and kinetic resolution of racemic DA cyclopropanes.
2018, 35(9): 1057-1066
doi: 10.11944/j.issn.1000-0518.2018.09.180117
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Two-dimensional graphdiyne has received widely attentions due to its outstanding physical and chemical properties. Many remarkable progresses of graphdiyne in the theories, preparations, and applications have been received in recent years. Based on its native particularities in the preparations and molecular structure, graphdiyne has already shown many promises in the traditional research areas, and brought important impacts in some new research directions, demonstrating that the graphdiyne has gradually become a hot research field. Its applications in electrochemical energy storage have received more and more attentions. This paper describes the original advantages of graphdiyne in the electrochemical energy storages, summarizes the developments in preparations, and mainly discusses the expansion of graphdiyne family via low-temperature synthesis and their electrochemical behaviors in storing the lithium/sodium ions.
Two-dimensional graphdiyne has received widely attentions due to its outstanding physical and chemical properties. Many remarkable progresses of graphdiyne in the theories, preparations, and applications have been received in recent years. Based on its native particularities in the preparations and molecular structure, graphdiyne has already shown many promises in the traditional research areas, and brought important impacts in some new research directions, demonstrating that the graphdiyne has gradually become a hot research field. Its applications in electrochemical energy storage have received more and more attentions. This paper describes the original advantages of graphdiyne in the electrochemical energy storages, summarizes the developments in preparations, and mainly discusses the expansion of graphdiyne family via low-temperature synthesis and their electrochemical behaviors in storing the lithium/sodium ions.
2018, 35(9): 1067-1075
doi: 10.11944/j.issn.1000-0518.2018.09.180164
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Cation redox chemistry is the most important energy storage mechanism of electrochemical energy storage technology. How to utilize redox active cations efficiently and quickly is the key to the development of electrical storage technology with both high power density and high energy density. The cationic state in colloid state can form thermodynamic equilibrium state and non-equilibrium state with high reactivity and fast reaction kinetics. In this paper, the colloidal state and the electrochemical energy storage limit of redox active cations are introduced, and the energy storage mechanism and the construction of the active colloid ion electrode are described from viewpoint of thermodynamics and kinetics. Using the high specific surface area of colloid, high ion adsorption capacity, and charge ion gradient distribution, the creative colloid supercapacitor battery solves the problem that the existing electrochemical energy storage materials can not have both high energy and high power, and the new application direction of the colloid system is also opened up.
Cation redox chemistry is the most important energy storage mechanism of electrochemical energy storage technology. How to utilize redox active cations efficiently and quickly is the key to the development of electrical storage technology with both high power density and high energy density. The cationic state in colloid state can form thermodynamic equilibrium state and non-equilibrium state with high reactivity and fast reaction kinetics. In this paper, the colloidal state and the electrochemical energy storage limit of redox active cations are introduced, and the energy storage mechanism and the construction of the active colloid ion electrode are described from viewpoint of thermodynamics and kinetics. Using the high specific surface area of colloid, high ion adsorption capacity, and charge ion gradient distribution, the creative colloid supercapacitor battery solves the problem that the existing electrochemical energy storage materials can not have both high energy and high power, and the new application direction of the colloid system is also opened up.
2018, 35(9): 1076-1092
doi: 10.11944/j.issn.1000-0518.2018.09.180165
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Lithium-ion batteries are the most widely used energy storage device, and currently, the rapid development of economy has put forward higher requirements on their performances. Electrode microstructure has significant influence on the battery performance, therefore, elaborate microstructure design and controllable preparation thereof is becoming one of the hot topics in this field. In this paper, according to the latest development trend of lithium ion batteries, the basic electrochemical process and the microstructural characterization technology of the lithium ion battery electrode are enumerated. Then the design and optimization of the electrode in recent years are summarized, and the key microstructural features are discussed. Based on an ideal electrode structure, the latest development in controllable electrode preparation technology is reviewed.
Lithium-ion batteries are the most widely used energy storage device, and currently, the rapid development of economy has put forward higher requirements on their performances. Electrode microstructure has significant influence on the battery performance, therefore, elaborate microstructure design and controllable preparation thereof is becoming one of the hot topics in this field. In this paper, according to the latest development trend of lithium ion batteries, the basic electrochemical process and the microstructural characterization technology of the lithium ion battery electrode are enumerated. Then the design and optimization of the electrode in recent years are summarized, and the key microstructural features are discussed. Based on an ideal electrode structure, the latest development in controllable electrode preparation technology is reviewed.
2018, 35(9): 1093-1101
doi: 10.11944/j.issn.1000-0518.2018.09.180180
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Water Splitting is an important method for hydrogen production in high purity and large quantities. Thus, developing high-performance, low-cost catalysts for hydrogen evolution reaction (HER) is of great importance. In this review, we systematically summarize the synthetic method for metal sulfide/phosphide-based catalysts as non-precious metal catalysts for HER reaction, and the method for enhancing the HER catalytic activity through constructing metal sulfide/phosphide with unique structure, which can provide guidance for developing new type HER catalysts with high catalytic activity.
Water Splitting is an important method for hydrogen production in high purity and large quantities. Thus, developing high-performance, low-cost catalysts for hydrogen evolution reaction (HER) is of great importance. In this review, we systematically summarize the synthetic method for metal sulfide/phosphide-based catalysts as non-precious metal catalysts for HER reaction, and the method for enhancing the HER catalytic activity through constructing metal sulfide/phosphide with unique structure, which can provide guidance for developing new type HER catalysts with high catalytic activity.
2018, 35(9): 1102-1106
doi: 10.11944/j.issn.1000-0518.2018.09.180136
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The mediator-based electrochemical method is a sensitive and reliable one toward water total toxicity. The in-situ cultivated microorganism can be used as the test organisms, which endows the method high sensitivity to the changes in the total toxicity of the target water, thus enabling the method suitable for the evolution of the exact level of complex pollution of water and the design of early warning system of water quality. Here, the advance of the mediator-based electrochemical method toward water total toxicity is reviewed in term of mechanism of toxicity determination, the use of mediator and microorganism, and so on. Finally, a future perspective of the method is presented.
The mediator-based electrochemical method is a sensitive and reliable one toward water total toxicity. The in-situ cultivated microorganism can be used as the test organisms, which endows the method high sensitivity to the changes in the total toxicity of the target water, thus enabling the method suitable for the evolution of the exact level of complex pollution of water and the design of early warning system of water quality. Here, the advance of the mediator-based electrochemical method toward water total toxicity is reviewed in term of mechanism of toxicity determination, the use of mediator and microorganism, and so on. Finally, a future perspective of the method is presented.
2018, 35(9): 1107-1112
doi: 10.11944/j.issn.1000-0518.2018.09.180170
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Design and development of simple, ultrasensitive, and high selective analytical techniques and methods for the clinical diagnosis and monitoring of a series of acute myocardial infarction (AMI) markers are urgently required for complicated sample matrix. Due to its good stability, high sensitivity, wide linear range, and good controllability, electrochemiluminescent (ECL) analysis technique is commonly used for low-level analytes. Combined with biosensing, it shows great promise in assaying low-level AMI biomarkers in complicated matrix such as biological fluids. This review presents the development of ECL sensing technique for AMI bioanalysis in recent five years. Some ECL probes, co-reactants, multianalyte biosensing methods and their application in AMI marker analysis have been introduced.
Design and development of simple, ultrasensitive, and high selective analytical techniques and methods for the clinical diagnosis and monitoring of a series of acute myocardial infarction (AMI) markers are urgently required for complicated sample matrix. Due to its good stability, high sensitivity, wide linear range, and good controllability, electrochemiluminescent (ECL) analysis technique is commonly used for low-level analytes. Combined with biosensing, it shows great promise in assaying low-level AMI biomarkers in complicated matrix such as biological fluids. This review presents the development of ECL sensing technique for AMI bioanalysis in recent five years. Some ECL probes, co-reactants, multianalyte biosensing methods and their application in AMI marker analysis have been introduced.
2018, 35(9): 1113-1125
doi: 10.11944/j.issn.1000-0518.2018.09.180169
Abstract:
Metal-organic frameworks (MOFs) is a kind of hybrid porous materials self-assembled by metal ions or clusters and organic ligands. Extremely high surface area and porosity, as well as adjustable structure and pore size endow MOFs with flexibility in designability and functionality. Because the metal ion centers, organic ligands and loaded guest molecules all could serve as luminescent centers, and respond specificly to ions or small molecules, Therefore, MOFs have plenty of applications in fluorescence detection. This article mainly reviews the research progress and application prospects of MOFs in fluorescence detection in recent years.
Metal-organic frameworks (MOFs) is a kind of hybrid porous materials self-assembled by metal ions or clusters and organic ligands. Extremely high surface area and porosity, as well as adjustable structure and pore size endow MOFs with flexibility in designability and functionality. Because the metal ion centers, organic ligands and loaded guest molecules all could serve as luminescent centers, and respond specificly to ions or small molecules, Therefore, MOFs have plenty of applications in fluorescence detection. This article mainly reviews the research progress and application prospects of MOFs in fluorescence detection in recent years.
2018, 35(9): 1126-1132
doi: 10.11944/j.issn.1000-0518.2018.09.180162
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Porous titania (TiO2) materials have important values and potentials in the fields of catalysis, energy, sensing, etc., due to their outstanding physical and chemical properties. In some applications associated with heterogeneous reactions, porous structures of TiO2 are advantageous because they have rich channels for mass transfer and surface active sites with tunable pore sizes. Nowadays, porous TiO2 materials are constantly developed and optimized in order to promote their industry applications. This review focuses on the research progress of porous TiO2 and their applications in photocatalysis, photogenerated electron storage, and gas sensing, in which the performance regulated through the design of structures and defects are introduced and discussed. Our research work about a series of porous TiO2 functional materials based on photochemical synthesis is specially introduced. Finally, the key issues and development prospects of porous TiO2 and their performances are also discussed.
Porous titania (TiO2) materials have important values and potentials in the fields of catalysis, energy, sensing, etc., due to their outstanding physical and chemical properties. In some applications associated with heterogeneous reactions, porous structures of TiO2 are advantageous because they have rich channels for mass transfer and surface active sites with tunable pore sizes. Nowadays, porous TiO2 materials are constantly developed and optimized in order to promote their industry applications. This review focuses on the research progress of porous TiO2 and their applications in photocatalysis, photogenerated electron storage, and gas sensing, in which the performance regulated through the design of structures and defects are introduced and discussed. Our research work about a series of porous TiO2 functional materials based on photochemical synthesis is specially introduced. Finally, the key issues and development prospects of porous TiO2 and their performances are also discussed.
2018, 35(9): 1133-1137
doi: 10.11944/j.issn.1000-0518.2018.09.180171
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Fluorescent film sensors have gained extensive attention in the past few decades because of their notable advantages such as high sensitivity, real-time detection, abundant fluorescence signals, easier device implementation, etc. With the fast development and promotion of microfabrication technology, integrated manufacturing, flexible device and Internet of Things, film-based fluorescent sensors have become one of the hot points of sensor studies. Based on the recent progress in our research, this article briefly reviews the development and applications of low-molecular mass compounds-based fluorescent film sensors, of which the applications in the vapor phase detection of explosives, illicit drugs, volatile organic contaminates and some signal molecules of diseases are specially addressed. In addition, problems and challenges limiting the construction of the film sensors are pointed out, and the futures of the relevant studies are prospected.
Fluorescent film sensors have gained extensive attention in the past few decades because of their notable advantages such as high sensitivity, real-time detection, abundant fluorescence signals, easier device implementation, etc. With the fast development and promotion of microfabrication technology, integrated manufacturing, flexible device and Internet of Things, film-based fluorescent sensors have become one of the hot points of sensor studies. Based on the recent progress in our research, this article briefly reviews the development and applications of low-molecular mass compounds-based fluorescent film sensors, of which the applications in the vapor phase detection of explosives, illicit drugs, volatile organic contaminates and some signal molecules of diseases are specially addressed. In addition, problems and challenges limiting the construction of the film sensors are pointed out, and the futures of the relevant studies are prospected.
2018, 35(9): 1138-1147
doi: 10.11944/j.issn.1000-0518.2018.09.180115
Abstract:
By heating the initial mixture with the molar ratio of n (Al2O3):n (P2O5):n (R):n (H2O)=1:1:1:277 (R=ethylenediamine (EDA) or 1, 3-propanediamine (1, 3-DAP)) at 180℃, a highly crystalline three-dimensional anionic open-framework aluminophosphate of AlPO4-12 or UiO-26 was obtained. The crystallization processes of both initial mixtures were investigated by X-ray diffraction analysis (XRD), elemental analysis, and pH measurement. The volume and the Hirshfeld charge on the N atom of the diprotonated EDA and 1, 3-DAP were calculated by the "atom volume and surface" module and the Dmol3 module in Materials Studio, respectively. Theoretical calculation shows that the charge on the N atom of diprotonated EDA or 1, 3-DAP is 0.073 e and 0.064 e (Hirshfeld), respectively. The corresponding charge density is 1.8573 and 1.3400 e/nm3 (Hirshfeld). The corresponding formal charge density is 25.44 and 20.94 e/nm3, respectively. The framework charge density of AlPO4-12 and UiO-26 is -6.1 e/nm3 and -4.6 e/nm3, respectively. These results indicate that the change in the length of carbon-chain connected to the N atom in the amino group can affect the amount of charge and the charge density on it, which accordingly affects its initial structure-directing ability, resulting the crystallization product changed from AlPO4-12 to UiO-26 with a smaller charge density.
By heating the initial mixture with the molar ratio of n (Al2O3):n (P2O5):n (R):n (H2O)=1:1:1:277 (R=ethylenediamine (EDA) or 1, 3-propanediamine (1, 3-DAP)) at 180℃, a highly crystalline three-dimensional anionic open-framework aluminophosphate of AlPO4-12 or UiO-26 was obtained. The crystallization processes of both initial mixtures were investigated by X-ray diffraction analysis (XRD), elemental analysis, and pH measurement. The volume and the Hirshfeld charge on the N atom of the diprotonated EDA and 1, 3-DAP were calculated by the "atom volume and surface" module and the Dmol3 module in Materials Studio, respectively. Theoretical calculation shows that the charge on the N atom of diprotonated EDA or 1, 3-DAP is 0.073 e and 0.064 e (Hirshfeld), respectively. The corresponding charge density is 1.8573 and 1.3400 e/nm3 (Hirshfeld). The corresponding formal charge density is 25.44 and 20.94 e/nm3, respectively. The framework charge density of AlPO4-12 and UiO-26 is -6.1 e/nm3 and -4.6 e/nm3, respectively. These results indicate that the change in the length of carbon-chain connected to the N atom in the amino group can affect the amount of charge and the charge density on it, which accordingly affects its initial structure-directing ability, resulting the crystallization product changed from AlPO4-12 to UiO-26 with a smaller charge density.
2018, 35(9): 1148-1154
doi: 10.11944/j.issn.1000-0518.2018.09.180217
Abstract:
The friction properties of polyurethane elastomers are of great significance in areas such as marine, automotive, and biomedical applications. However, the fine design of friction properties of such materials through chemical modification strategies still has urgent needs in research and application prospects. In this work, p-phenylene diisocyanate (PPDI) and polytetramethylene ether glycol (PTMG) were used, and the PPDI-based polyurethane elastomers with different degrees of cross-linking were synthesized through varing the molar ratio of two chain extenders of 1, 4-butanediol and trimethylolpropane. Results of the Fourier transform attenuated total reflection spectra (FTIR-ATR), wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC) indicate that the crystallinity of both hard segment and soft segment in polyurethane elastomer is inhibited with the increase of cross-linking degree. Meanwhile, the results of mechanical test show that the elastic modulus of the material decreases, while the friction coefficient of PPDI-based polyurethane elastomer increases. In addition, the hysteresis loop curve shows that the change in the degree of cross-linking also affects the damping properties of the PPDI-based polyurethane elastomer, and the difference in the damping of the polyurethane elastomer is also reflected in the dependence of the friction performance on the rate. This work therefore proposes that by using different degrees of crossl-inking, the crystallinity of hard and soft segments in PPDI-based polyurethane can be changed, which leads to the difference in the elastic and the loss modulus of the material, and the friction properties can thus be controlled, which provides a simple-to-achieve and effective way for the regulation of frictional properties of PPDI-based polyurethane elastomers.
The friction properties of polyurethane elastomers are of great significance in areas such as marine, automotive, and biomedical applications. However, the fine design of friction properties of such materials through chemical modification strategies still has urgent needs in research and application prospects. In this work, p-phenylene diisocyanate (PPDI) and polytetramethylene ether glycol (PTMG) were used, and the PPDI-based polyurethane elastomers with different degrees of cross-linking were synthesized through varing the molar ratio of two chain extenders of 1, 4-butanediol and trimethylolpropane. Results of the Fourier transform attenuated total reflection spectra (FTIR-ATR), wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC) indicate that the crystallinity of both hard segment and soft segment in polyurethane elastomer is inhibited with the increase of cross-linking degree. Meanwhile, the results of mechanical test show that the elastic modulus of the material decreases, while the friction coefficient of PPDI-based polyurethane elastomer increases. In addition, the hysteresis loop curve shows that the change in the degree of cross-linking also affects the damping properties of the PPDI-based polyurethane elastomer, and the difference in the damping of the polyurethane elastomer is also reflected in the dependence of the friction performance on the rate. This work therefore proposes that by using different degrees of crossl-inking, the crystallinity of hard and soft segments in PPDI-based polyurethane can be changed, which leads to the difference in the elastic and the loss modulus of the material, and the friction properties can thus be controlled, which provides a simple-to-achieve and effective way for the regulation of frictional properties of PPDI-based polyurethane elastomers.
