Polyurea(PUA)is widely valued in protective coatings and structural reinforcement because of its impressive mechanical strength and resistance to corrosion.Its high flammability,together with the poor dispersion that ...Polyurea(PUA)is widely valued in protective coatings and structural reinforcement because of its impressive mechanical strength and resistance to corrosion.Its high flammability,together with the poor dispersion that often comes with simply blending in flame retardants,continues to limit its use in demanding environments.To overcome these issues,this study introduces a different approach.We grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO)onto the surface of a metal-organic framework(MOF)and then partially amino-functionalized the DOPO layer,ultimately creating an amino-modified DOPO-MOF hybrid.The introduced amino groups can directly react with the isocyanate(-NCO)groups in the PUA matrix,allowing the flame-retardant component to be integrated via reactive integration rather than physical blending.This approach helps avoid the interfacial defects and the mechanical weakening typically observed in conventional blending.With 5 wt% ZIF-67@DOPO-NH2 added to the PUA system,the composite successfully reached a UL-94 V-0 classification and showed a notable increase in limiting oxygen index(LOI),from19.2% to 23.8%.The peak heat release rate and total heat release dropped by 36.3% and 38.7%,respectively.Meanwhile,the tensile strength decreased from 25.74 to 22.52 MPa,while the elongation at break remained above 300%,indicating that the material maintained excellent toughness.展开更多
The development of gradient lubrication materials is critical for numerous biomedical applications,particularly in magnifying mechanical properties and service longevity.Herein,we present an innovative approach to fab...The development of gradient lubrication materials is critical for numerous biomedical applications,particularly in magnifying mechanical properties and service longevity.Herein,we present an innovative approach to fabricate biomimetic gradient lubrication hydrogel through the synergistic integration of three-dimensional(3D)printed metal-organic frameworks(MOFs)nanoparticle network hydrogel skeletons with bioinspired lubrication design.Specifically,robust hydrogel skeletons were engineered through single or multi-material 3D printing,followed by the in situ growth of MOFs nanoparticles within this hydrogel network to create a reinforced,load-bearing architecture.Subsequently,biomimetic lubrication capability was enabled by mechanically coupling another lubricating hydrogel within 3D-printed MOFs nanoparticle network hydrogel skeleton.The superficial layer is highly lubricious to ensure low coefficient of friction(~0.1141)and wear resistance(40,000 cycles),while the deeper layer is stiffer to afford the obligatory mechanical support(fracture strength~2.50 MPa).Furthermore,the gradient architecture stiffness of the hydrogel can be modulated by manipulating the spatial distribution of MOFs within the 3D-printed hydrogel skeleton.As a proof-of-concept,biomimetic gradient hydrogel meniscus structures with C-and O-shaped configurations were constructed by leveraging multi-material 3D printing,demonstrating exceptional lubrication performance.This innovative biomimetic design opens new avenues for creating implantable biomedical gradient lubricating materials with reinforced mechanical and lubrication performance.展开更多
A composite metal-organic frameworks(MOFs)structure,designated as Co-hmta@La-salen,was synthesized through coordination interactions between a one-dimensional lanthanum MOFs(La-salen)with high density of uncoordinated...A composite metal-organic frameworks(MOFs)structure,designated as Co-hmta@La-salen,was synthesized through coordination interactions between a one-dimensional lanthanum MOFs(La-salen)with high density of uncoordinated imine(-CH=N-)groups and a cobalt-based MOFs(Co-hmta)structure prepared using hydrogen bonding stacking with hexamethylenetetramine(hmta)as the organic ligand.Subsequently,the Co-hmta@La-salen composite was chosen as a template for the pyrolysis process to synthesize a La(OH)_(3)supported metallic Co catalyst incorporating carbon-nitrogen(Co/La(OH)_(3)-CNhmta)catalyst.The catalytic results show that Co/La(OH)_(3)-CN-hmta(54%and 46%selectivity for aniline and N-phenylbenzylamine,respectively)displays superior cascade performance compared to classic Co/La(OH)_(3)-CN-nit catalyst(69%and 31%selectivity for aniline and N-phenylbenzylamine,respectively).Moreover,the kinetic test results indicate that N-alkylation is the rate-limiting step of the overall cascade reaction.The Co/La(OH)_(3)-CN-hmta catalyst can be separated from the reaction system using a magnet,and it also exhibits good cyclic stability.All of these suggest that the“MOFs plus MOFs via coordination”templating method can be employed as an efficient strategy for the preparation of supported catalysts.展开更多
基金financially supported by Natural Science Foundation of Shandong Province(Grant No.ZR2021ME019).
文摘Polyurea(PUA)is widely valued in protective coatings and structural reinforcement because of its impressive mechanical strength and resistance to corrosion.Its high flammability,together with the poor dispersion that often comes with simply blending in flame retardants,continues to limit its use in demanding environments.To overcome these issues,this study introduces a different approach.We grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO)onto the surface of a metal-organic framework(MOF)and then partially amino-functionalized the DOPO layer,ultimately creating an amino-modified DOPO-MOF hybrid.The introduced amino groups can directly react with the isocyanate(-NCO)groups in the PUA matrix,allowing the flame-retardant component to be integrated via reactive integration rather than physical blending.This approach helps avoid the interfacial defects and the mechanical weakening typically observed in conventional blending.With 5 wt% ZIF-67@DOPO-NH2 added to the PUA system,the composite successfully reached a UL-94 V-0 classification and showed a notable increase in limiting oxygen index(LOI),from19.2% to 23.8%.The peak heat release rate and total heat release dropped by 36.3% and 38.7%,respectively.Meanwhile,the tensile strength decreased from 25.74 to 22.52 MPa,while the elongation at break remained above 300%,indicating that the material maintained excellent toughness.
基金support from the National Key Research and Development Program of China(2022YFB4600101)the National Natural Science Foundation of China(52505231 and 52175201)+5 种基金the Key R&D Program of Shandong Province(2024CXPT035)the Research Program of Science and Technology Department of Gansu Province(24JRRA059,24JRRA044 and 24ZDGA014)the Science Fund of Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai(AMGM2024F12)the Innovation and Entrepreneurship Team Prject of YEDA(2021TD007)the Special Supporting Project for Provincial Leading Talents of Yantai,the Major Program(ZYFZFX-2)the Fundamental Research Special Zone Project of the Lanzhou Institute of Chemical Physics,CAS,the Special Research Assistant Project of the Chinese Academy of Sciences,and the Taishan Scholars Program.
文摘The development of gradient lubrication materials is critical for numerous biomedical applications,particularly in magnifying mechanical properties and service longevity.Herein,we present an innovative approach to fabricate biomimetic gradient lubrication hydrogel through the synergistic integration of three-dimensional(3D)printed metal-organic frameworks(MOFs)nanoparticle network hydrogel skeletons with bioinspired lubrication design.Specifically,robust hydrogel skeletons were engineered through single or multi-material 3D printing,followed by the in situ growth of MOFs nanoparticles within this hydrogel network to create a reinforced,load-bearing architecture.Subsequently,biomimetic lubrication capability was enabled by mechanically coupling another lubricating hydrogel within 3D-printed MOFs nanoparticle network hydrogel skeleton.The superficial layer is highly lubricious to ensure low coefficient of friction(~0.1141)and wear resistance(40,000 cycles),while the deeper layer is stiffer to afford the obligatory mechanical support(fracture strength~2.50 MPa).Furthermore,the gradient architecture stiffness of the hydrogel can be modulated by manipulating the spatial distribution of MOFs within the 3D-printed hydrogel skeleton.As a proof-of-concept,biomimetic gradient hydrogel meniscus structures with C-and O-shaped configurations were constructed by leveraging multi-material 3D printing,demonstrating exceptional lubrication performance.This innovative biomimetic design opens new avenues for creating implantable biomedical gradient lubricating materials with reinforced mechanical and lubrication performance.
基金Project supported by the Natural Science Foundation of Jiangsu Province (BK20210066)Natural Science Foundation of Heilongjiang Province (ZD2022E007).
文摘A composite metal-organic frameworks(MOFs)structure,designated as Co-hmta@La-salen,was synthesized through coordination interactions between a one-dimensional lanthanum MOFs(La-salen)with high density of uncoordinated imine(-CH=N-)groups and a cobalt-based MOFs(Co-hmta)structure prepared using hydrogen bonding stacking with hexamethylenetetramine(hmta)as the organic ligand.Subsequently,the Co-hmta@La-salen composite was chosen as a template for the pyrolysis process to synthesize a La(OH)_(3)supported metallic Co catalyst incorporating carbon-nitrogen(Co/La(OH)_(3)-CNhmta)catalyst.The catalytic results show that Co/La(OH)_(3)-CN-hmta(54%and 46%selectivity for aniline and N-phenylbenzylamine,respectively)displays superior cascade performance compared to classic Co/La(OH)_(3)-CN-nit catalyst(69%and 31%selectivity for aniline and N-phenylbenzylamine,respectively).Moreover,the kinetic test results indicate that N-alkylation is the rate-limiting step of the overall cascade reaction.The Co/La(OH)_(3)-CN-hmta catalyst can be separated from the reaction system using a magnet,and it also exhibits good cyclic stability.All of these suggest that the“MOFs plus MOFs via coordination”templating method can be employed as an efficient strategy for the preparation of supported catalysts.
