To address the poor mechanical performance and improve the tribological properties of self-lubricating polyphenylene sulfide/irradiation treated polytetrafluoroethylene(PPS/i-PTFE)blends,different aspect ratio carbon ...To address the poor mechanical performance and improve the tribological properties of self-lubricating polyphenylene sulfide/irradiation treated polytetrafluoroethylene(PPS/i-PTFE)blends,different aspect ratio carbon fibers(i.e.,PSCF:50,SCF:about 429)were introduced as reinforcement fillers.The results showed that the hybriding of PSCF and SCF at certain mass ratios exhibited simultaneous enhancement of mechanical and tribological performance for PPS/i-PTFE blend through the construction of synergistic lubrication and mechanical interlocking network.Specifically,the flexural strength and modulus of PPS/i-PTFE were increased by 125.6% and 389.3%,the friction coefficient and specific wear rate were decreased by 13.9% and 95%,respectively.It was worth noting that PPS composites possessed excellent integrated performance which were able to withstand sliding action under high PV(≥10 MPa·m/s)conditions,as assessed by a customized pin-on-disc tester.This work demonstrated that the formation of intact lubricating film combined with the enhanced thermal and mechanical properties were favorable for improving the tribological properties of PPS-based composites,which makes them suitable for advanced engineering applications.展开更多
Several new enediynes with long chain alkyl groups were synthesized through Sonogashira coupling reactions between long chain alkynes and（Z）-1,2-dichloroethene. These enediynes（1） were then subjected to thermal Be...Several new enediynes with long chain alkyl groups were synthesized through Sonogashira coupling reactions between long chain alkynes and（Z）-1,2-dichloroethene. These enediynes（1） were then subjected to thermal Bergman cyclization in a refluxing diphenyl ether bath under vacuum to obtain conjugated polyphenylenes with the weight-average molecular weights up to 4.9 × 103 g·mol·1. The occurrence of Bergman cyclization was confirmed by 1H-NMR, 13C-NMR, and IR spectroscopic analysis. These polyphenylenes are fully soluble in common organic solvents and exhibit good thermal stability. The optical properties of the polyphenylenes were investigated by UV-Vis absorption and photoluminescence（PL） spectroscopies. A blue emission was observed for all these polyphenylenes.展开更多
A fibrous strong base anion exchanger （QAPPS） was prepared for the first time via chloromethylation and quaternary amination reaction of polyphenylene sulfide fiber （PPS）, and its physical-chemical structure and a...A fibrous strong base anion exchanger （QAPPS） was prepared for the first time via chloromethylation and quaternary amination reaction of polyphenylene sulfide fiber （PPS）, and its physical-chemical structure and adsorption behavior for Cr（VI） were characterized by FT- IR, Energy Dispersive Spectrometry, TG-DTG, elemental analysis and batch adsorptive technique, respectively. The novel fibrous adsorbent could effectively adsorb Cr（VI） over the pH range 1-12, the maximum adsorption capacity was 166.39 mg/g at pH 3.5, and the adsorption behavior could be described well by Langmuir isotherm equation model. The adsorption kinetics was studied using pseudo first-order and pseudo second-order models, and the 4/2 and equilibrium adsorption time were 5 and 20 min respectively when initial Cr（VI） concentration was 100 mg/L. The saturated fibers could be regenerated rapidly by a mixed solution of 0.5 mol/L NaOH and 0.5 mol/L NaCl, and the adsorption capacity was well maintained after six adsorption-desorption cycles.展开更多
A series of novel chelating fibers containing sulfur, nitrogen, oxygen heteroatoms were prepared via the functionalization of chloromethylated polyphenylene sulfide （CMPPS）. The structures, micromorpholo- gy and phy...A series of novel chelating fibers containing sulfur, nitrogen, oxygen heteroatoms were prepared via the functionalization of chloromethylated polyphenylene sulfide （CMPPS）. The structures, micromorpholo- gy and physicochemical properties of these fibrous adsorptive materials were characterized by FT-IR, elementary analysis, TG and SEM-EDS. The results show that chelating fibers had high functional group contents （3.94 mmol/g for thiourea, 3.85 mmol/g for mercapto, 5.00 mmol/g for methylamine and 6.07 mmol/g for ethylenediamine, respectively）. Owing to the unique matrix of polyphenylene sulfide fiber, these fibrous adsorbents possess excellent thermostability. This synthetic method proved a simple and efficient way for the preparation of chelating fibers.展开更多
The effect of pressure-induced flow（PIF） processing on the mechanical properties of noncontinuous carbon fiber（CF） reinforced polyphenylene sulfide（PPS） composites was investigated. A series of CF/PPS composites...The effect of pressure-induced flow（PIF） processing on the mechanical properties of noncontinuous carbon fiber（CF） reinforced polyphenylene sulfide（PPS） composites was investigated. A series of CF/PPS composites under different processing conditions were prepared through PIF-processing. SEM observations showed that the interfaces adhesion between CFs and PPS became stronger and ductile fracture mainly occurred in PPS matrix. This brought to a great increase of both strength and toughness by about 2 folds, when the composites were processed at 240 ℃ and under 263 MPa. The results in differential scanning calorimetry（DSC） and X-ray diffraction（XRD） measurements indicated more regular crystalline structures and orientation of lamellae formed during PIF-processing.展开更多
Self-lubricating polyphenylene sulfide(PPS)composites were fabricated by constructing a segregated network structure using the co-deposition method.Both carboxyl-functionalized multi-walled carbon nanotubes(CNTs)and s...Self-lubricating polyphenylene sulfide(PPS)composites were fabricated by constructing a segregated network structure using the co-deposition method.Both carboxyl-functionalized multi-walled carbon nanotubes(CNTs)and silicon carbide(SiC)were successfully coated on the surface of PPS powders with the aid of self-polymerization of dopamine(PDA)and co-polymerization between PDA and polyethyleneimine(PEI),thereby forming PPS@PDA-CNTs-SiC hierarchical reinforcing hybrids.Results showed that the thermal conductivity of PPS@PDA-CNTs-SiC(0.97 W/(m K))is about 120%higher than that of PPS/CNTs/SiC.The friction coefficient(0.193)and specific wear rate(2.50×10^(-5)mm^(3)/(N m))of PPS@PDA-CNTs-SiC are 18.9%and 50%lower than those of PPS/CNTs/SiC,respectively.The enhanced thermal conductivity of PPS@PDA-CNTs-SiC contributes to rapid dissipation of frictional heat at the sliding interface which protects the polymer substrate from being destroyed or peeled,thereby improving the tribological performance.This work provides new insights into expanding the application of self-lubricating polymer composites in the fields where efficient heat dissipation is also a primary concern.展开更多
Blends of polyphenylene sulfide (PPS) containing trace amounts of branching and/or cross-linking in chain and Polyamide-66 (PA-66) have been prepared by melt blending. The rheological behavior of PPS/PA-66 blends has ...Blends of polyphenylene sulfide (PPS) containing trace amounts of branching and/or cross-linking in chain and Polyamide-66 (PA-66) have been prepared by melt blending. The rheological behavior of PPS/PA-66 blends has been studied by means of capillary rheometer, and compared with PPS. The effects of shear rate, shear stress and temperature on the how of PPS/PA-66 blends and PPS are discussed. The non-Newtonian indexes and the activation energies of viscous how are obtained. The results show that the apparent viscosity of PPS/PA-66 blends is not sensitive to shear rate and stress, but decreases with the elevation of temperature. On the contrary, the apparent viscosity of the PPS decreases obviously with the increasing of shear rate and shear stress, but it is increased by the elevation of temperature.展开更多
基金financially supported by the National Natural Science Foundation of China(No.52103040)China Postdoctoral Science Foundation(No.2020M673217)the Fundamental Research Funds for the Central Universities(No.2023SCU12022)。
文摘To address the poor mechanical performance and improve the tribological properties of self-lubricating polyphenylene sulfide/irradiation treated polytetrafluoroethylene(PPS/i-PTFE)blends,different aspect ratio carbon fibers(i.e.,PSCF:50,SCF:about 429)were introduced as reinforcement fillers.The results showed that the hybriding of PSCF and SCF at certain mass ratios exhibited simultaneous enhancement of mechanical and tribological performance for PPS/i-PTFE blend through the construction of synergistic lubrication and mechanical interlocking network.Specifically,the flexural strength and modulus of PPS/i-PTFE were increased by 125.6% and 389.3%,the friction coefficient and specific wear rate were decreased by 13.9% and 95%,respectively.It was worth noting that PPS composites possessed excellent integrated performance which were able to withstand sliding action under high PV(≥10 MPa·m/s)conditions,as assessed by a customized pin-on-disc tester.This work demonstrated that the formation of intact lubricating film combined with the enhanced thermal and mechanical properties were favorable for improving the tribological properties of PPS-based composites,which makes them suitable for advanced engineering applications.
基金financially supported by the National Natural Science Foundation of China(Nos.20874026 and 91023008)Ph.D.Programs Foundation of Ministry of Education of China(20100074110002)+1 种基金the Fundamental Research Funds for the Central Universities,Shanghai Leading Academic Discipline Project(B502)AH thanks the"Eastern Scholar Professorship"support from Shanghai local government
文摘Several new enediynes with long chain alkyl groups were synthesized through Sonogashira coupling reactions between long chain alkynes and（Z）-1,2-dichloroethene. These enediynes（1） were then subjected to thermal Bergman cyclization in a refluxing diphenyl ether bath under vacuum to obtain conjugated polyphenylenes with the weight-average molecular weights up to 4.9 × 103 g·mol·1. The occurrence of Bergman cyclization was confirmed by 1H-NMR, 13C-NMR, and IR spectroscopic analysis. These polyphenylenes are fully soluble in common organic solvents and exhibit good thermal stability. The optical properties of the polyphenylenes were investigated by UV-Vis absorption and photoluminescence（PL） spectroscopies. A blue emission was observed for all these polyphenylenes.
基金support of the National Natural Science Foundation of China (No. 20574063,21004055)
文摘A fibrous strong base anion exchanger （QAPPS） was prepared for the first time via chloromethylation and quaternary amination reaction of polyphenylene sulfide fiber （PPS）, and its physical-chemical structure and adsorption behavior for Cr（VI） were characterized by FT- IR, Energy Dispersive Spectrometry, TG-DTG, elemental analysis and batch adsorptive technique, respectively. The novel fibrous adsorbent could effectively adsorb Cr（VI） over the pH range 1-12, the maximum adsorption capacity was 166.39 mg/g at pH 3.5, and the adsorption behavior could be described well by Langmuir isotherm equation model. The adsorption kinetics was studied using pseudo first-order and pseudo second-order models, and the 4/2 and equilibrium adsorption time were 5 and 20 min respectively when initial Cr（VI） concentration was 100 mg/L. The saturated fibers could be regenerated rapidly by a mixed solution of 0.5 mol/L NaOH and 0.5 mol/L NaCl, and the adsorption capacity was well maintained after six adsorption-desorption cycles.
基金support by the National Natural Science Foundation of China(No.20574063)Doctoral Foundation of Ministry of Education of China(No. 20104101110005)
文摘A series of novel chelating fibers containing sulfur, nitrogen, oxygen heteroatoms were prepared via the functionalization of chloromethylated polyphenylene sulfide （CMPPS）. The structures, micromorpholo- gy and physicochemical properties of these fibrous adsorptive materials were characterized by FT-IR, elementary analysis, TG and SEM-EDS. The results show that chelating fibers had high functional group contents （3.94 mmol/g for thiourea, 3.85 mmol/g for mercapto, 5.00 mmol/g for methylamine and 6.07 mmol/g for ethylenediamine, respectively）. Owing to the unique matrix of polyphenylene sulfide fiber, these fibrous adsorbents possess excellent thermostability. This synthetic method proved a simple and efficient way for the preparation of chelating fibers.
基金Funded by the National Natural Science Foundation of China(No.21404023)the Foundation of State Key Laboratory for Modification of Chemical Fibers and Polymer Materials(No.LK1417)the Fundamental Research Funds for the Central Universities(2232015D-10)
文摘The effect of pressure-induced flow（PIF） processing on the mechanical properties of noncontinuous carbon fiber（CF） reinforced polyphenylene sulfide（PPS） composites was investigated. A series of CF/PPS composites under different processing conditions were prepared through PIF-processing. SEM observations showed that the interfaces adhesion between CFs and PPS became stronger and ductile fracture mainly occurred in PPS matrix. This brought to a great increase of both strength and toughness by about 2 folds, when the composites were processed at 240 ℃ and under 263 MPa. The results in differential scanning calorimetry（DSC） and X-ray diffraction（XRD） measurements indicated more regular crystalline structures and orientation of lamellae formed during PIF-processing.
基金financially supported by the China Postdoctoral Science Foundation(No.2020M673217)the National Natural Science Foundation of China(No.51703137)the Fundamental Research Funds for the Central Universities
文摘Self-lubricating polyphenylene sulfide(PPS)composites were fabricated by constructing a segregated network structure using the co-deposition method.Both carboxyl-functionalized multi-walled carbon nanotubes(CNTs)and silicon carbide(SiC)were successfully coated on the surface of PPS powders with the aid of self-polymerization of dopamine(PDA)and co-polymerization between PDA and polyethyleneimine(PEI),thereby forming PPS@PDA-CNTs-SiC hierarchical reinforcing hybrids.Results showed that the thermal conductivity of PPS@PDA-CNTs-SiC(0.97 W/(m K))is about 120%higher than that of PPS/CNTs/SiC.The friction coefficient(0.193)and specific wear rate(2.50×10^(-5)mm^(3)/(N m))of PPS@PDA-CNTs-SiC are 18.9%and 50%lower than those of PPS/CNTs/SiC,respectively.The enhanced thermal conductivity of PPS@PDA-CNTs-SiC contributes to rapid dissipation of frictional heat at the sliding interface which protects the polymer substrate from being destroyed or peeled,thereby improving the tribological performance.This work provides new insights into expanding the application of self-lubricating polymer composites in the fields where efficient heat dissipation is also a primary concern.
基金This work was supported by the National High Technology Program Fund(863)of China.
文摘Blends of polyphenylene sulfide (PPS) containing trace amounts of branching and/or cross-linking in chain and Polyamide-66 (PA-66) have been prepared by melt blending. The rheological behavior of PPS/PA-66 blends has been studied by means of capillary rheometer, and compared with PPS. The effects of shear rate, shear stress and temperature on the how of PPS/PA-66 blends and PPS are discussed. The non-Newtonian indexes and the activation energies of viscous how are obtained. The results show that the apparent viscosity of PPS/PA-66 blends is not sensitive to shear rate and stress, but decreases with the elevation of temperature. On the contrary, the apparent viscosity of the PPS decreases obviously with the increasing of shear rate and shear stress, but it is increased by the elevation of temperature.
