Due to their non-flammability,remarkable flexibility,ease of processing,and design versatility,polymer-based electrolytes containing polyethers have emerged as pivotal materials for high-energy-density and safe lithiu...Due to their non-flammability,remarkable flexibility,ease of processing,and design versatility,polymer-based electrolytes containing polyethers have emerged as pivotal materials for high-energy-density and safe lithium-metal batteries.Although polyethers provide sufficient sites for Li⁺transport through ether-oxygen coordination,they still exhibit low room-temperature ionic conductivity and poor oxidation stability,which remains a critical obstacle to the commercialization of lithium-metal batteries.Given fluorine's strong electronegativity and the excellent stability of C-F bonds,fluorination strategies have proven effective in enhancing the oxidative stability of polymer-based electrolytes and extending the cycling life of lithium-metal batteries.Notably,incorporating fluorine into ether-based polymer-based electrolytes can simultaneously improve ionic conductivity,mechanical properties,and the formation of stable electrode/electrolyte interfaces.In this review,we comprehensively examine the design of fluoro-functionalized polyether electrolytes for advanced lithium-metal batteries and their impact on battery performance.Our primary objectives are to elucidate the structure-property relationships of fluoro-functionalized polyether electrolytes and to explore their mechanisms in improving interfacial stability and electrochemical performance.Furthermore,we discuss the key challenges and future development directions of fluoro-functionalized polyether electrolytes for solid-state lithium-metal battery applications,and propose practical strategies to address these issues.展开更多
Incorporation of acetal groups in the backbone is a potent strategy to create polymers that are cleavable or degradable under acidic conditions.We report here an in-depth study on the ring-closing-opening copolymeriza...Incorporation of acetal groups in the backbone is a potent strategy to create polymers that are cleavable or degradable under acidic conditions.We report here an in-depth study on the ring-closing-opening copolymerization of o-phthalaldehyde(OPA)and epoxide using Lewis pair type two-component organocatalysts for producing acetal-functionalized polyether and polyurethane.Notably,triethylborane as the Lewis acid,in comparison with tri(n-butyl)borane,more effectively enhances the polymerization activity by mitigating borane-induced reduction of the aldehyde group into extra initiating(borinic ester)species.Density functional theory(DFT)calculations present comparable energy barriers of OPA-epoxide cross-propagation and epoxide self-propagation,which is consistent with the experimental finding that an alternating-rich copolymer comprising mostly OPA-epoxide units but also epoxide-epoxide linkages is produced.In particular,when epoxide is added in a large excess,the product becomes a polyether containing acetal functionalities in the central part of the backbone and thus being convertible into polyurethane with refined acid degradability.展开更多
Over the last half-century,polyether ether ketone(PEEK)has emerged as a widely adopted thermoplastic polymer,primarily due to its lower density,exceptional mechanical properties,high-temperature and chemical resistanc...Over the last half-century,polyether ether ketone(PEEK)has emerged as a widely adopted thermoplastic polymer,primarily due to its lower density,exceptional mechanical properties,high-temperature and chemical resistance,and biocompatibility.PEEK and its composites have found extensive applications across various fields,including machinery,aerospace,military equipment,electronics,and biomedicine,positioning themselves as promising substitutes for traditional metal structures.Nevertheless,achieving optimal performance and functional molding of PEEK and its composites presents a formidable challenge,given their inherent characteristics,such as semi-crystallinity,high melting temperature,heightened viscosity,low dielectric coefficient,and hydrophobic properties.In this paper,we present a comprehensive review of the molding methods and processes of PEEK and its composites,including extrusion molding,hot compression molding,injection molding,and 3D printing.We also introduce typical innovative applications within the fields of mechanics,electricity,and biomedicine while elucidating methodologies that leverage the distinctive advantages of PEEK and its composites.Additionally,we summarize research findings related to manipulating the properties of PEEK and its composites through the optimization of machine parameters,process variables,and material structural adjustments.Finally,we contemplate the prevailing development trends and outline prospective avenues for further research in the advancement and molding of PEEK and its composites.展开更多
A high performance thermosetting epoxy resin crosslinkable at room temperature was obtained via directly moulding diglycidyl ether of bisphenol A(DGEBA) and flexibleα,ω-bisamino(n-alkylene)phenyl terminated poly...A high performance thermosetting epoxy resin crosslinkable at room temperature was obtained via directly moulding diglycidyl ether of bisphenol A(DGEBA) and flexibleα,ω-bisamino(n-alkylene)phenyl terminated poly(ethylene glycol).The influences of the n-alkylene inserted in aminophenyl of flexible amino-terminated polythers(ATPE) on the mechanical properties,fractographs and curing kinetics of the ATPE-DGEBA cured products were studied.The results show that the insertion of n-alkylene group into the aminophenyl group of the ATPE,on one hand,can significantly increase the strain relaxation rate and decrease glass transition temperature of the ATPE-DGEBA cured products,resulting in slight decrease of the Young’s modulus and tensile strength,and significant increase of the toughness and elongation of the ATPE-DGEBA cured products.On the other hand,it can remarkably enhance the reactivity of amine with epoxy,much accelerating the curing rate of the ATPE-DGEBA systems.The activation energy of DGEBA cured by BAPTPE,BAMPTPE and BAEPTPE was 53.1,28.5 and 25.4 kJ·mol;,respectively.The as-obtained ATPE-DGEBA cured products are homogeneous, transparent,and show excellent mechanical properties including tensile strength and toughness.Thus they are promising to have important applications in structure adhesives,casting bulk materials,functional coatings,cryogenic engineering, damping and sound absorbing materials.展开更多
A novel liquid hyperbranched polyether epoxy(HBPEE)based on commercially available hydroquinone(HQ)and 1,1,1-trihydroxymethylpropane triglycidyl ether(TMPGE)was synthesized through an A2+B3 one-step proton transfer po...A novel liquid hyperbranched polyether epoxy(HBPEE)based on commercially available hydroquinone(HQ)and 1,1,1-trihydroxymethylpropane triglycidyl ether(TMPGE)was synthesized through an A2+B3 one-step proton transfer polymerization.In order to improve the toughness,the synthesized HBPEE was mixed with diglycidyl ether of bisphenol A(DGEBA)in different ratios to form hybrids and cured with triethylenetetramine(TETA).Thermal and mechanical properties of the cured hybrids were evaluated.Results show that addition of HBPEE can improve the toughness of cured hybrids remarkably at〈20 wt%loading,without compromising the tensile strength.However,the glass transition temperature(Tg)of the cured hybrids decreases with increasing HBPEE content.Fracture surface images from scanning electron microscope show oriented fibrils in hybrids containing HBPEE.The formation and orientation of the fibrils can absorb energy under impact and lead to an improvement of toughness.Furthermore,based on the morphology of fractured surfaces and the single Tg in each hybrid,no sign of phase separation was found in the cured hybrid systems.As a result,the toughening mechanism could be explained by in situ homogeneous toughening mechanism rather than phase separation mechanism.展开更多
Nitrate ester plasticized polyether(NEPE)is a kind of high-energy solid propellant that has both good mechanical properties and high specific impulse.However,its unique composition makes its combustion mechanism diffe...Nitrate ester plasticized polyether(NEPE)is a kind of high-energy solid propellant that has both good mechanical properties and high specific impulse.However,its unique composition makes its combustion mechanism different from both double-base propellants and composite propellants.In order to study the combustion mechanism of NEPE propellants,we improved the free radical cracking model of previous research to make it capable of predicting the burning rate of NEPE propellants.To study the combustion characteristics and provide data support for the model,an experimental system was built and four kinds of NEPE propellants with different compositions and grain size distributions were tested.The results show that our modified model can reflect the combustion characteristics of NEPE propellants with an acceptable accuracy.The difference between the model and the experimental data is mainly caused by uncertain environmental factors and the ignorance of interactions between components.Both the experimental data and the results predicted by the model show that increasing the backpressure helps to increase the burning rate of NEPE propellants.Furthermore,the grain size of the oxidizer inside the NEPE propellant has a more severe impact on the burning rate but a lighter impact on the burning rate pressure exponent in comparison with the grain size of aluminum.For aluminum-free NEPE propellants,the reaction in the gas phase is dominant in the combustion process while adding aluminum into the propellant makes the solid phase dominant in the final stage.The combustion of fine aluminum particles near the burning surface generates heat feedback to the burning surface which evidently influences the surface temperature.However,the agglomeration of coarse aluminum particles has little effect on the burning surface temperature.展开更多
Ethylene oxide(EO) and propylene oxide(PO) random copolyethers were synthesized by the sequential addition of the mixture of ethylene oxide and propylene oxide to propylene glycol (initiator) in the presence of potass...Ethylene oxide(EO) and propylene oxide(PO) random copolyethers were synthesized by the sequential addition of the mixture of ethylene oxide and propylene oxide to propylene glycol (initiator) in the presence of potassium hydroxide(KOH), and characterized with infrared spectrum(FTIR) and nuclear magnetism resonance(NMR). The effects of catalyst concentration, reaction temperature, charging rate and EO/PO mixture ratio on the polymerization reaction were investigated. It was revealed that the optimal reaction condition is the ratio of 2.5∶1 000(KOH mass vs. product mass), at 114.6℃ and pressure below 0.4 MPa. The residual KOH was neutralized by phosphoric acid(H 3PO 4). Then the crude copolyether was refined with adsorbents, and the refined copolyether, which contains less than 0.7 μg/ml K+, was obtained as colorless, viscous liquid.展开更多
Three new catalysts based on the silica gel supported polyether ionic liquids(ILs), i.e., [HO-PECH-MIM]ClSi, [H2N-PECH-MIM]Cl-Si, and [HOOC-PECH-MIM]Cl-Si, were prepared, and their chemical structures were characteriz...Three new catalysts based on the silica gel supported polyether ionic liquids(ILs), i.e., [HO-PECH-MIM]ClSi, [H2N-PECH-MIM]Cl-Si, and [HOOC-PECH-MIM]Cl-Si, were prepared, and their chemical structures were characterized by infrared(IR) spectroscopy and nuclear magnetic resonance(NMR) spectroscopy. Thermogravimetric analyzer(TG), X-ray diffractometer(XRD) and scanning electron microscope(SEM) were used to evaluate their thermal stability,crystalline structure and apparent morphology, respectively. Surface areas of the prepared catalysts were calculated by the Brunauer-Emmett-Teller(BET) method. The catalytic reaction for the synthesis of propylene carbonate(PC) using CO_2 and propylene oxide(PO) in the presence of the prepared catalysts was studied. The influences of times of recycling and catalyst structure on catalytic performance were also investigated. The experimental results showed that the silica gel supported polyether ILs catalysts successfully prepared under mild condition could possess the advantages of high activity, excellent thermal stability, good selectivity and easy recycling, while the phase transition of the liquid polyether ILs catalysts was also achieved. When the reaction temperature was 90 °C, the CO_2 pressure was 2.0 MPa and the dosage of the catalyst was 2.5%, [HOOC-PECH-MIM]Cl-Si was found to have the best catalytic performance in the catalytic process, with the conversion rate reaching 100% and the selectivity equating to 98.2%. The conversion rate and selectivity still could reach more than 90% even after the catalyst was reused for 15 times.展开更多
A series of segmented polyether-polyester polyurethane with amorphous hydrophilic soft segment domains were prepared from 4,4'- diphenylmethane diisocyanate (MDI), polybutylene adipate (Glycol) 2000 (PBA2000), and...A series of segmented polyether-polyester polyurethane with amorphous hydrophilic soft segment domains were prepared from 4,4'- diphenylmethane diisocyanate (MDI), polybutylene adipate (Glycol) 2000 (PBA2000), and polyethylene glycol 1000 (PEG1000), with 1,4-butanediol (BDO) as the chain extender. Furthermore, several representative properties of the polyurethanes, such as moisture permeability, water resistance, hydrophilic property, and phase inversion temperature, were investigated. The studies show that the structure and concentration of soft segment have a remarkable effect on the main application properties of polyurethane. On the contrary, the functional properties of the polyurethane are almost not affected by its hard segment.展开更多
Fluorinated polyether dendritic sectors 4, 7 and 10 from the first to the third generations, respectively, were prepared by a convergent approach from readily available pentafluorophenol, phloroglucinol and 1,3-dibrom...Fluorinated polyether dendritic sectors 4, 7 and 10 from the first to the third generations, respectively, were prepared by a convergent approach from readily available pentafluorophenol, phloroglucinol and 1,3-dibromopropane. These dendritic sectors have good solubility properties and are stable in both acidic and basic media. Hence they are useful dendritic building blocks for the preparation of functional dendrimers.展开更多
Polyether-polyurethane zwitterionomers based on 4, 4'-diphenylmethane diisocyanate(MDI), methyl diethanolamine (MDEA), and polytetramethylene oxide glycol (PTMO) werestudied with variable-temperature wide-line ~1H...Polyether-polyurethane zwitterionomers based on 4, 4'-diphenylmethane diisocyanate(MDI), methyl diethanolamine (MDEA), and polytetramethylene oxide glycol (PTMO) werestudied with variable-temperature wide-line ~1H NMR. It is found that upon ionization, degree ofphase separation in the polymer system decreased at first due to the loss of hard segmentregularity, while further ionization increased the degree of phase separation through increasinghard phase cohesion and difference of polarity between hard and soft segments.展开更多
A new reactive graft copolymer, poly(tetramethylene glycol)-graft-omega-propyl sodium sulfonate-poly(ethylene glycol) (PTMG-g-PEG-CH2CH2CH2SO3-Na+), was synthesized by the cationic polymerization of alpha-omega-bifunc...A new reactive graft copolymer, poly(tetramethylene glycol)-graft-omega-propyl sodium sulfonate-poly(ethylene glycol) (PTMG-g-PEG-CH2CH2CH2SO3-Na+), was synthesized by the cationic polymerization of alpha-omega-bifunctional PEG macromonomer ((sic)CH2-PEG-CH2CH2CH2SO3Na) and THF. The obtained copolymer exhibits the expected structure as indicated by the result of characterization. Two amino acids (L-arginine, L-tyrosine) were covalently attached to the copolymer after converting the sulfonate group, to sulfonyl chloride. So the new reactive graft copolymer (PTMG-g-PEG-CH2CH2CH2SO3-Na+) is expected to be very useful in attachment of potentially bioactive moieties to polymer via a hydrophilic PEG spacer.展开更多
The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS)....The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.展开更多
Ionic conductivity values for segmented polyether polyurethaneurea (PEUU) complexes with LiClO_4 were determined and values as high as~1.1×10-4 S·cm-1 at 353K and~1.0×10-5S·cm-1 at 30...Ionic conductivity values for segmented polyether polyurethaneurea (PEUU) complexes with LiClO_4 were determined and values as high as~1.1×10-4 S·cm-1 at 353K and~1.0×10-5S·cm-1 at 306K were achieved. The ionic conductivity data were analyzed using the VTF (Vogel-Tamman-Fulcher) equation and WLF (Williams-Landel-Ferry) type equation. Values have been estimated for the 'apparent' activation energies of ion transport from VTF equation and they lie in the range 2.70—5.53 kJ·mol-1.展开更多
Complexes of comb-shaped polyether and lithium aromatic sulfonates bearing different negative charge number were prepared by in situ thermal polymerization. Their conductivity depends deeply on salt content, ambient t...Complexes of comb-shaped polyether and lithium aromatic sulfonates bearing different negative charge number were prepared by in situ thermal polymerization. Their conductivity depends deeply on salt content, ambient temperature and negative charge number of the added salts. Results show that anions can be partly immobilized by increasing their negative charges at lower temperature. Against discharge time the short circuit current of the battery (Li/complex film/Li_x V_3O_8) is stabilized by increasing the anionic charge number of the complex.展开更多
Three polystyrene resins containing polyether oligomers as extractants were synthesized andtheir extraction properties were studied. Gold (III) ion could be extracted rapidly by the resins(T1/2,<lmin. )with high...Three polystyrene resins containing polyether oligomers as extractants were synthesized andtheir extraction properties were studied. Gold (III) ion could be extracted rapidly by the resins(T1/2,<lmin. )with high efficiency and capacity (for LS-B resin that were 99. 8% and 95. 8mg/gRrespectively) from aqueous solution but most of the co-existing metal ions such as Pd (II),Cu(II), Zn (II), Pb (II) and Cd (II) were remained. The extraction capacity and strippingpercentage for gold (III) remained unchanged in four extraction-stripping cycles. The resins also showed good column extraction-elution properties.展开更多
Temperature-accelerated in vitro degradation was established to estimate the longevity of polyurethane applied for long-term implantation.However,the prediction did not correlate well with the data from clinical expla...Temperature-accelerated in vitro degradation was established to estimate the longevity of polyurethane applied for long-term implantation.However,the prediction did not correlate well with the data from clinical explants and the rationality of accelerated in vitro test is still in a controversial due to the deviation.To improve the accuracy of the in vitro prediction,the influence of hydrogen bonding(HB)on the accelerated hydrolysis of silicone based polyetherurethans(SPEUs)extended with three side chains.Combining the temperature-controlled FTIR and the physical properties after temperature-accelerated in vitro degradation,it was demonstrated that side chain could increase the degree of hydrogen bond dissociation at higher temperature,resulting in the decrease of the calculated activation energy(Ea)of hydrolysis.At low temperatures,changes in surface morphology and molar mass of PEUs are minimal and HB are less easily dissociated,which had barely impact on the hydrolysis resistance.It was proposed that the Ea will not be impacted and that the accuracy of prediction will be increased if the acceleration temperature is lower than 70℃ and HB change is less than 15%.展开更多
Proton conducting composite membranes from sulfonated polyether ether ketone and SiO2 for direct methanol fuel cell(DMFC)application were prepared with sulfonated polyether ether ketone(SPEEK)and tetracethoxy silane(T...Proton conducting composite membranes from sulfonated polyether ether ketone and SiO2 for direct methanol fuel cell(DMFC)application were prepared with sulfonated polyether ether ketone(SPEEK)and tetracethoxy silane(TEOS)by sol-gel method.The covalent crosslinking structure was formed between—SO3H of SPEEK via SiO2.The SEM images show that the interfacial compatibility of SPEEK and SiO2 is improved obviously and SiO2 disperses uniformly in the polymer matrix and the particle diameter of SiO2 does not exceed 40 nm.The proton conductivity of composite membranes decreases slightly compared with the SPEEK membrane while the methanol permeability and swelling of composite membrane are improved remarkablely owing to covalent cross-linking between—SO3H and SiO2.展开更多
Nuclear magnetic resonance(NMR)is an advanced technique for the molecular weight(MW)determination of polymers at quantitative conditions.In this study,we investigate the effect of liquid1H-NMR instrumental setting ...Nuclear magnetic resonance(NMR)is an advanced technique for the molecular weight(MW)determination of polymers at quantitative conditions.In this study,we investigate the effect of liquid1H-NMR instrumental setting parameters on the MW determination of polyether diols,namely poly(ethylene glycol)(PEG)and poly(tetramethylene oxide)(PTMO)diols,using hydroxymethylene groups as chain-ends.Our results show that the protons in chain-ends have larger spin-lattice relaxation time(T1)than those in main chains.To let most of the excited protons relax to the equilibrium state,the delay time(d1)should be much larger than T1of end-groups.When13C decoupling is inactive,the relative errors can be greater than 60%,due to the13C-coupled proton satellite peaks,which can overlap with chain-end groups or be misassigned as chainends.The optimal quantitative NMR conditions for the MW estimation of polyethers are revealed below:standard pulse with inverted gated13C decoupling pulse sequence,32 scans,2.0 s acquisition time in 90 degree of flip angle and 30 s d1.The MWs determined from1H quantitative NMR are all smaller than those from SEC which are relative to polystyrene(PS)standards,since the size of polyether chains is larger than that of PS with the same MW.In addition,the MW obtained from SEC for PTMOs shows larger overestimation than PEGs,suggesting PEG chains are more flexible than PTMO’s.展开更多
A brominated hyperbranched polyether has been synthesized from cyanuric chloride and sodium salt of tetrabromobisphenol-A by an A2 + B3 approach. The synthesized polyether was characterized by ^1H-NMR, ^13C-NMR, UV, ...A brominated hyperbranched polyether has been synthesized from cyanuric chloride and sodium salt of tetrabromobisphenol-A by an A2 + B3 approach. The synthesized polyether was characterized by ^1H-NMR, ^13C-NMR, UV, FTIR spectroscopy and X-ray diffraction studies, measurements of solution viscosity, molecular weight and solubility and elemental and thermogravimetric analyses. The flame retardancy of the synthesized polyether and its blends with commercially available plasticized poly(vinyl chloride) (PVC) and low density polyethylene (LDPE) was investigated by measurements of limiting oxygen index (LOI) value and thermogravimetric analysis. The properties are compared with a non-halogenated similar type of bisphenol-A based aromatic polyether after blending at different dose levels with the same base polymers. The LOI values of these blends indicated that these hyperbranched polyethers acted as flame retardant additives, and antimony trioxide had prominent synergistic effect with the bromo hyperbranched polyether for the above base polymers, and an increment of 4 to 6 units in LOI values was observed.展开更多
基金support from Guangdong Basic and Applied Basic Research Foundation(2024A1515012363)Natural Science Foundation of Top Talent of Shenzhen Technology University(grant no.GDRC202315)+1 种基金support from the Department of Education of Guangdong Province(2022ZDZX3024)the National Natural Science Foundation of China(no.52174255).
摘要Due to their non-flammability,remarkable flexibility,ease of processing,and design versatility,polymer-based electrolytes containing polyethers have emerged as pivotal materials for high-energy-density and safe lithium-metal batteries.Although polyethers provide sufficient sites for Li⁺transport through ether-oxygen coordination,they still exhibit low room-temperature ionic conductivity and poor oxidation stability,which remains a critical obstacle to the commercialization of lithium-metal batteries.Given fluorine's strong electronegativity and the excellent stability of C-F bonds,fluorination strategies have proven effective in enhancing the oxidative stability of polymer-based electrolytes and extending the cycling life of lithium-metal batteries.Notably,incorporating fluorine into ether-based polymer-based electrolytes can simultaneously improve ionic conductivity,mechanical properties,and the formation of stable electrode/electrolyte interfaces.In this review,we comprehensively examine the design of fluoro-functionalized polyether electrolytes for advanced lithium-metal batteries and their impact on battery performance.Our primary objectives are to elucidate the structure-property relationships of fluoro-functionalized polyether electrolytes and to explore their mechanisms in improving interfacial stability and electrochemical performance.Furthermore,we discuss the key challenges and future development directions of fluoro-functionalized polyether electrolytes for solid-state lithium-metal battery applications,and propose practical strategies to address these issues.
基金financially supported by the National Key R&D Program of China(No.2022YFC2805103)the National Natural Science Foundation of China(Nos.52022031 and 52263001)the Foundation from Qinghai Science and Technology Department(No.2022-ZJ-944Q)。
摘要Incorporation of acetal groups in the backbone is a potent strategy to create polymers that are cleavable or degradable under acidic conditions.We report here an in-depth study on the ring-closing-opening copolymerization of o-phthalaldehyde(OPA)and epoxide using Lewis pair type two-component organocatalysts for producing acetal-functionalized polyether and polyurethane.Notably,triethylborane as the Lewis acid,in comparison with tri(n-butyl)borane,more effectively enhances the polymerization activity by mitigating borane-induced reduction of the aldehyde group into extra initiating(borinic ester)species.Density functional theory(DFT)calculations present comparable energy barriers of OPA-epoxide cross-propagation and epoxide self-propagation,which is consistent with the experimental finding that an alternating-rich copolymer comprising mostly OPA-epoxide units but also epoxide-epoxide linkages is produced.In particular,when epoxide is added in a large excess,the product becomes a polyether containing acetal functionalities in the central part of the backbone and thus being convertible into polyurethane with refined acid degradability.
基金supported by the National Key R&D Program of China(No.2022YFC2401903)the“Pioneer”and the“Leading Goose”R&D Program of Zhejiang Province(No.2023C01170)+1 种基金the National Natural Science Foundation of China(No.52205424)the Key Project of Science and Technology Innovation 2025 of Ningbo(No.2023Z029),China.
摘要Over the last half-century,polyether ether ketone(PEEK)has emerged as a widely adopted thermoplastic polymer,primarily due to its lower density,exceptional mechanical properties,high-temperature and chemical resistance,and biocompatibility.PEEK and its composites have found extensive applications across various fields,including machinery,aerospace,military equipment,electronics,and biomedicine,positioning themselves as promising substitutes for traditional metal structures.Nevertheless,achieving optimal performance and functional molding of PEEK and its composites presents a formidable challenge,given their inherent characteristics,such as semi-crystallinity,high melting temperature,heightened viscosity,low dielectric coefficient,and hydrophobic properties.In this paper,we present a comprehensive review of the molding methods and processes of PEEK and its composites,including extrusion molding,hot compression molding,injection molding,and 3D printing.We also introduce typical innovative applications within the fields of mechanics,electricity,and biomedicine while elucidating methodologies that leverage the distinctive advantages of PEEK and its composites.Additionally,we summarize research findings related to manipulating the properties of PEEK and its composites through the optimization of machine parameters,process variables,and material structural adjustments.Finally,we contemplate the prevailing development trends and outline prospective avenues for further research in the advancement and molding of PEEK and its composites.
基金supported by the National 863 Plan(No.2006AA03A209)New Century Excellent Talent Plan (No.NECT-05-0660) from Ministry of EducationDefense Basic Research Item(No.D1420061057)
摘要A high performance thermosetting epoxy resin crosslinkable at room temperature was obtained via directly moulding diglycidyl ether of bisphenol A(DGEBA) and flexibleα,ω-bisamino(n-alkylene)phenyl terminated poly(ethylene glycol).The influences of the n-alkylene inserted in aminophenyl of flexible amino-terminated polythers(ATPE) on the mechanical properties,fractographs and curing kinetics of the ATPE-DGEBA cured products were studied.The results show that the insertion of n-alkylene group into the aminophenyl group of the ATPE,on one hand,can significantly increase the strain relaxation rate and decrease glass transition temperature of the ATPE-DGEBA cured products,resulting in slight decrease of the Young’s modulus and tensile strength,and significant increase of the toughness and elongation of the ATPE-DGEBA cured products.On the other hand,it can remarkably enhance the reactivity of amine with epoxy,much accelerating the curing rate of the ATPE-DGEBA systems.The activation energy of DGEBA cured by BAPTPE,BAMPTPE and BAEPTPE was 53.1,28.5 and 25.4 kJ·mol;,respectively.The as-obtained ATPE-DGEBA cured products are homogeneous, transparent,and show excellent mechanical properties including tensile strength and toughness.Thus they are promising to have important applications in structure adhesives,casting bulk materials,functional coatings,cryogenic engineering, damping and sound absorbing materials.
基金supported by the Natural Science Foundation of Beijing(No.2092023)National Natural Science Foundation of China(No.51173012)the Fundamental Research Funds for the Central Universities(No.ZZ0912)
摘要A novel liquid hyperbranched polyether epoxy(HBPEE)based on commercially available hydroquinone(HQ)and 1,1,1-trihydroxymethylpropane triglycidyl ether(TMPGE)was synthesized through an A2+B3 one-step proton transfer polymerization.In order to improve the toughness,the synthesized HBPEE was mixed with diglycidyl ether of bisphenol A(DGEBA)in different ratios to form hybrids and cured with triethylenetetramine(TETA).Thermal and mechanical properties of the cured hybrids were evaluated.Results show that addition of HBPEE can improve the toughness of cured hybrids remarkably at〈20 wt%loading,without compromising the tensile strength.However,the glass transition temperature(Tg)of the cured hybrids decreases with increasing HBPEE content.Fracture surface images from scanning electron microscope show oriented fibrils in hybrids containing HBPEE.The formation and orientation of the fibrils can absorb energy under impact and lead to an improvement of toughness.Furthermore,based on the morphology of fractured surfaces and the single Tg in each hybrid,no sign of phase separation was found in the cured hybrid systems.As a result,the toughening mechanism could be explained by in situ homogeneous toughening mechanism rather than phase separation mechanism.
基金Project supported by the National Natural Science Foundation of China(No.11572349)the Natural Science Foundation of Hunan Province(No.2018JJ3606),China。
摘要Nitrate ester plasticized polyether(NEPE)is a kind of high-energy solid propellant that has both good mechanical properties and high specific impulse.However,its unique composition makes its combustion mechanism different from both double-base propellants and composite propellants.In order to study the combustion mechanism of NEPE propellants,we improved the free radical cracking model of previous research to make it capable of predicting the burning rate of NEPE propellants.To study the combustion characteristics and provide data support for the model,an experimental system was built and four kinds of NEPE propellants with different compositions and grain size distributions were tested.The results show that our modified model can reflect the combustion characteristics of NEPE propellants with an acceptable accuracy.The difference between the model and the experimental data is mainly caused by uncertain environmental factors and the ignorance of interactions between components.Both the experimental data and the results predicted by the model show that increasing the backpressure helps to increase the burning rate of NEPE propellants.Furthermore,the grain size of the oxidizer inside the NEPE propellant has a more severe impact on the burning rate but a lighter impact on the burning rate pressure exponent in comparison with the grain size of aluminum.For aluminum-free NEPE propellants,the reaction in the gas phase is dominant in the combustion process while adding aluminum into the propellant makes the solid phase dominant in the final stage.The combustion of fine aluminum particles near the burning surface generates heat feedback to the burning surface which evidently influences the surface temperature.However,the agglomeration of coarse aluminum particles has little effect on the burning surface temperature.
摘要Ethylene oxide(EO) and propylene oxide(PO) random copolyethers were synthesized by the sequential addition of the mixture of ethylene oxide and propylene oxide to propylene glycol (initiator) in the presence of potassium hydroxide(KOH), and characterized with infrared spectrum(FTIR) and nuclear magnetism resonance(NMR). The effects of catalyst concentration, reaction temperature, charging rate and EO/PO mixture ratio on the polymerization reaction were investigated. It was revealed that the optimal reaction condition is the ratio of 2.5∶1 000(KOH mass vs. product mass), at 114.6℃ and pressure below 0.4 MPa. The residual KOH was neutralized by phosphoric acid(H 3PO 4). Then the crude copolyether was refined with adsorbents, and the refined copolyether, which contains less than 0.7 μg/ml K+, was obtained as colorless, viscous liquid.
基金supported by the National Natural Science Foundation of China (NSFC 21706163)the Liaoning Province Department of Education Foundation (LQGD2017020)
摘要Three new catalysts based on the silica gel supported polyether ionic liquids(ILs), i.e., [HO-PECH-MIM]ClSi, [H2N-PECH-MIM]Cl-Si, and [HOOC-PECH-MIM]Cl-Si, were prepared, and their chemical structures were characterized by infrared(IR) spectroscopy and nuclear magnetic resonance(NMR) spectroscopy. Thermogravimetric analyzer(TG), X-ray diffractometer(XRD) and scanning electron microscope(SEM) were used to evaluate their thermal stability,crystalline structure and apparent morphology, respectively. Surface areas of the prepared catalysts were calculated by the Brunauer-Emmett-Teller(BET) method. The catalytic reaction for the synthesis of propylene carbonate(PC) using CO_2 and propylene oxide(PO) in the presence of the prepared catalysts was studied. The influences of times of recycling and catalyst structure on catalytic performance were also investigated. The experimental results showed that the silica gel supported polyether ILs catalysts successfully prepared under mild condition could possess the advantages of high activity, excellent thermal stability, good selectivity and easy recycling, while the phase transition of the liquid polyether ILs catalysts was also achieved. When the reaction temperature was 90 °C, the CO_2 pressure was 2.0 MPa and the dosage of the catalyst was 2.5%, [HOOC-PECH-MIM]Cl-Si was found to have the best catalytic performance in the catalytic process, with the conversion rate reaching 100% and the selectivity equating to 98.2%. The conversion rate and selectivity still could reach more than 90% even after the catalyst was reused for 15 times.
基金Key Foundation of Shannxi Province,China (No.04JK181)China Textile Industry Association(No.2007049)
摘要A series of segmented polyether-polyester polyurethane with amorphous hydrophilic soft segment domains were prepared from 4,4'- diphenylmethane diisocyanate (MDI), polybutylene adipate (Glycol) 2000 (PBA2000), and polyethylene glycol 1000 (PEG1000), with 1,4-butanediol (BDO) as the chain extender. Furthermore, several representative properties of the polyurethanes, such as moisture permeability, water resistance, hydrophilic property, and phase inversion temperature, were investigated. The studies show that the structure and concentration of soft segment have a remarkable effect on the main application properties of polyurethane. On the contrary, the functional properties of the polyurethane are almost not affected by its hard segment.
摘要Fluorinated polyether dendritic sectors 4, 7 and 10 from the first to the third generations, respectively, were prepared by a convergent approach from readily available pentafluorophenol, phloroglucinol and 1,3-dibromopropane. These dendritic sectors have good solubility properties and are stable in both acidic and basic media. Hence they are useful dendritic building blocks for the preparation of functional dendrimers.
基金This work is supported by the National Natural Science Foundation of China and the Foundation of Nation’s Education Committee for Young Scientists.
摘要Polyether-polyurethane zwitterionomers based on 4, 4'-diphenylmethane diisocyanate(MDI), methyl diethanolamine (MDEA), and polytetramethylene oxide glycol (PTMO) werestudied with variable-temperature wide-line ~1H NMR. It is found that upon ionization, degree ofphase separation in the polymer system decreased at first due to the loss of hard segmentregularity, while further ionization increased the degree of phase separation through increasinghard phase cohesion and difference of polarity between hard and soft segments.
基金Supported by the National Natural Science Foundation of China and Huoyindong Education Foundation
摘要A new reactive graft copolymer, poly(tetramethylene glycol)-graft-omega-propyl sodium sulfonate-poly(ethylene glycol) (PTMG-g-PEG-CH2CH2CH2SO3-Na+), was synthesized by the cationic polymerization of alpha-omega-bifunctional PEG macromonomer ((sic)CH2-PEG-CH2CH2CH2SO3Na) and THF. The obtained copolymer exhibits the expected structure as indicated by the result of characterization. Two amino acids (L-arginine, L-tyrosine) were covalently attached to the copolymer after converting the sulfonate group, to sulfonyl chloride. So the new reactive graft copolymer (PTMG-g-PEG-CH2CH2CH2SO3-Na+) is expected to be very useful in attachment of potentially bioactive moieties to polymer via a hydrophilic PEG spacer.
摘要The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.
摘要Ionic conductivity values for segmented polyether polyurethaneurea (PEUU) complexes with LiClO_4 were determined and values as high as~1.1×10-4 S·cm-1 at 353K and~1.0×10-5S·cm-1 at 306K were achieved. The ionic conductivity data were analyzed using the VTF (Vogel-Tamman-Fulcher) equation and WLF (Williams-Landel-Ferry) type equation. Values have been estimated for the 'apparent' activation energies of ion transport from VTF equation and they lie in the range 2.70—5.53 kJ·mol-1.
摘要Complexes of comb-shaped polyether and lithium aromatic sulfonates bearing different negative charge number were prepared by in situ thermal polymerization. Their conductivity depends deeply on salt content, ambient temperature and negative charge number of the added salts. Results show that anions can be partly immobilized by increasing their negative charges at lower temperature. Against discharge time the short circuit current of the battery (Li/complex film/Li_x V_3O_8) is stabilized by increasing the anionic charge number of the complex.
摘要Three polystyrene resins containing polyether oligomers as extractants were synthesized andtheir extraction properties were studied. Gold (III) ion could be extracted rapidly by the resins(T1/2,<lmin. )with high efficiency and capacity (for LS-B resin that were 99. 8% and 95. 8mg/gRrespectively) from aqueous solution but most of the co-existing metal ions such as Pd (II),Cu(II), Zn (II), Pb (II) and Cd (II) were remained. The extraction capacity and strippingpercentage for gold (III) remained unchanged in four extraction-stripping cycles. The resins also showed good column extraction-elution properties.
基金financially supported by the National Natural Science Foundation of China(No.51973134)the State Key Research Development Program of China(No.2020YFC1107000)+1 种基金the NSAF(No.U1930204)Interdisciplinary Innovation Projects of West China Hospital of Stomatology Sichuan University(No.RD-03-202001)。
摘要Temperature-accelerated in vitro degradation was established to estimate the longevity of polyurethane applied for long-term implantation.However,the prediction did not correlate well with the data from clinical explants and the rationality of accelerated in vitro test is still in a controversial due to the deviation.To improve the accuracy of the in vitro prediction,the influence of hydrogen bonding(HB)on the accelerated hydrolysis of silicone based polyetherurethans(SPEUs)extended with three side chains.Combining the temperature-controlled FTIR and the physical properties after temperature-accelerated in vitro degradation,it was demonstrated that side chain could increase the degree of hydrogen bond dissociation at higher temperature,resulting in the decrease of the calculated activation energy(Ea)of hydrolysis.At low temperatures,changes in surface morphology and molar mass of PEUs are minimal and HB are less easily dissociated,which had barely impact on the hydrolysis resistance.It was proposed that the Ea will not be impacted and that the accuracy of prediction will be increased if the acceleration temperature is lower than 70℃ and HB change is less than 15%.
摘要Proton conducting composite membranes from sulfonated polyether ether ketone and SiO2 for direct methanol fuel cell(DMFC)application were prepared with sulfonated polyether ether ketone(SPEEK)and tetracethoxy silane(TEOS)by sol-gel method.The covalent crosslinking structure was formed between—SO3H of SPEEK via SiO2.The SEM images show that the interfacial compatibility of SPEEK and SiO2 is improved obviously and SiO2 disperses uniformly in the polymer matrix and the particle diameter of SiO2 does not exceed 40 nm.The proton conductivity of composite membranes decreases slightly compared with the SPEEK membrane while the methanol permeability and swelling of composite membrane are improved remarkablely owing to covalent cross-linking between—SO3H and SiO2.
基金financially supported by the National Natural Science Foundation of China(Nos.22231008 and 22071167)the Natural Science Foundation of Jiangsu Higher Education Institutions of China(No.22KJA150005)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions。
摘要Nuclear magnetic resonance(NMR)is an advanced technique for the molecular weight(MW)determination of polymers at quantitative conditions.In this study,we investigate the effect of liquid1H-NMR instrumental setting parameters on the MW determination of polyether diols,namely poly(ethylene glycol)(PEG)and poly(tetramethylene oxide)(PTMO)diols,using hydroxymethylene groups as chain-ends.Our results show that the protons in chain-ends have larger spin-lattice relaxation time(T1)than those in main chains.To let most of the excited protons relax to the equilibrium state,the delay time(d1)should be much larger than T1of end-groups.When13C decoupling is inactive,the relative errors can be greater than 60%,due to the13C-coupled proton satellite peaks,which can overlap with chain-end groups or be misassigned as chainends.The optimal quantitative NMR conditions for the MW estimation of polyethers are revealed below:standard pulse with inverted gated13C decoupling pulse sequence,32 scans,2.0 s acquisition time in 90 degree of flip angle and 30 s d1.The MWs determined from1H quantitative NMR are all smaller than those from SEC which are relative to polystyrene(PS)standards,since the size of polyether chains is larger than that of PS with the same MW.In addition,the MW obtained from SEC for PTMOs shows larger overestimation than PEGs,suggesting PEG chains are more flexible than PTMO’s.
基金supported by the CSIR,New Delhi(No.01(1868/03/EMR-II))
摘要A brominated hyperbranched polyether has been synthesized from cyanuric chloride and sodium salt of tetrabromobisphenol-A by an A2 + B3 approach. The synthesized polyether was characterized by ^1H-NMR, ^13C-NMR, UV, FTIR spectroscopy and X-ray diffraction studies, measurements of solution viscosity, molecular weight and solubility and elemental and thermogravimetric analyses. The flame retardancy of the synthesized polyether and its blends with commercially available plasticized poly(vinyl chloride) (PVC) and low density polyethylene (LDPE) was investigated by measurements of limiting oxygen index (LOI) value and thermogravimetric analysis. The properties are compared with a non-halogenated similar type of bisphenol-A based aromatic polyether after blending at different dose levels with the same base polymers. The LOI values of these blends indicated that these hyperbranched polyethers acted as flame retardant additives, and antimony trioxide had prominent synergistic effect with the bromo hyperbranched polyether for the above base polymers, and an increment of 4 to 6 units in LOI values was observed.