This study focused on the production of polypropylene(PP)/silver(Ag)composites via additive manufacturing.This study aimed to enhance the quality of medical-grade PP in material extrusion(MEX)three-dimensional printin...This study focused on the production of polypropylene(PP)/silver(Ag)composites via additive manufacturing.This study aimed to enhance the quality of medical-grade PP in material extrusion(MEX)three-dimensional printing(3DP)by improving its mechanical properties while simultaneously adding antibacterial properties.The latter can find extremely important and versatile properties that are applicable in defense and security domains.PP/Ag nanocomposites were prepared using a novel method based on a reaction occurring while mixing appropriate quantities of the starting polymers and additives,namely polyvinylpyrrolidone(PVP)as the matrix material and silver nitrate(AgNO_(3))as the filler.This process produced three-dimensional(3D)printed filaments,which were then used to create specimens for a series of standardized tests.It was found that the mechanical properties of the nanocomposites were enhanced in relation to pristine PP,especially for the PP matrix with various loadings of AgNO_(3)and PVP,such as 5.0 wt%and 2.5 wt%,respectively.The voids,inclusions,and actual-to-nominal dimensions also showed improved results.The 3DP specimens exhibited a more effective biocidal performance against Staphylococcus aureus than Escherichia coli,which developed an inhibition zone only in the case of PP with filler loading percentages of AgNO_(3)and PVP at 10.0 wt%and 5.0 wt%,respectively Compounds possessing such properties can be beneficial for various applications requiring increased mechanical properties and biocidal capabilities,such as in the Defence or medical industries.展开更多
The synthetic path of a catalyst determines its morphology,species,and performance,and in-situ monitoring the catalyst formation process is fascinating and challenging.Herein,a newly developed synchrotron radiation sm...The synthetic path of a catalyst determines its morphology,species,and performance,and in-situ monitoring the catalyst formation process is fascinating and challenging.Herein,a newly developed synchrotron radiation smallangle X-ray scattering/X-ray diffraction/X-ray absorption fine structure(SAXS/XRD/XAFS)combined technique was used to in-situ monitor the isothermal-isobaric synthesis process of CO_(2)-assisted(BiO)_(2)CO_(3)(BOC)photocatalyst,and the atomic near-neighbor structure,crystalline structure and nanoscale particle size evolution with reaction time were simultaneously captured.The results show that both polyvinyl pyrrolidone and CO_(2)formed uniformly-distributed nano-sized scatterers in the Bi-based precursor solution,presenting short-range ordered structures to a certain extent.The as-prepared BOC catalytic particles underwent the evolution process of initial Bi(OH)3 precipitate,early-stage formed KBiO_(2)molecules,intermediate amorphous(BiO)4CO3(OH)2 nanoparticles,and finally crystallized flower-like BOC particles self-assembled by nanosheets.The flower-like BOC particles,Bi/BOC composite,and Bi nanospheres were further prepared with different synthesis paths.Flower-like BOC particles showed the best photocatalytic degradation performance of RhB.Scavenger experiment and theoretical calculation revealed the photocatalytic mechanisms of BOC.This work has implications for path-dependent synthesis of other catalysts.展开更多
文摘This study focused on the production of polypropylene(PP)/silver(Ag)composites via additive manufacturing.This study aimed to enhance the quality of medical-grade PP in material extrusion(MEX)three-dimensional printing(3DP)by improving its mechanical properties while simultaneously adding antibacterial properties.The latter can find extremely important and versatile properties that are applicable in defense and security domains.PP/Ag nanocomposites were prepared using a novel method based on a reaction occurring while mixing appropriate quantities of the starting polymers and additives,namely polyvinylpyrrolidone(PVP)as the matrix material and silver nitrate(AgNO_(3))as the filler.This process produced three-dimensional(3D)printed filaments,which were then used to create specimens for a series of standardized tests.It was found that the mechanical properties of the nanocomposites were enhanced in relation to pristine PP,especially for the PP matrix with various loadings of AgNO_(3)and PVP,such as 5.0 wt%and 2.5 wt%,respectively.The voids,inclusions,and actual-to-nominal dimensions also showed improved results.The 3DP specimens exhibited a more effective biocidal performance against Staphylococcus aureus than Escherichia coli,which developed an inhibition zone only in the case of PP with filler loading percentages of AgNO_(3)and PVP at 10.0 wt%and 5.0 wt%,respectively Compounds possessing such properties can be beneficial for various applications requiring increased mechanical properties and biocidal capabilities,such as in the Defence or medical industries.
基金supported by the National Natural Science Foundation of China(12305372)the National Key R&D Program(2017YFA0403001 and 2022YFA1603802)of China。
文摘The synthetic path of a catalyst determines its morphology,species,and performance,and in-situ monitoring the catalyst formation process is fascinating and challenging.Herein,a newly developed synchrotron radiation smallangle X-ray scattering/X-ray diffraction/X-ray absorption fine structure(SAXS/XRD/XAFS)combined technique was used to in-situ monitor the isothermal-isobaric synthesis process of CO_(2)-assisted(BiO)_(2)CO_(3)(BOC)photocatalyst,and the atomic near-neighbor structure,crystalline structure and nanoscale particle size evolution with reaction time were simultaneously captured.The results show that both polyvinyl pyrrolidone and CO_(2)formed uniformly-distributed nano-sized scatterers in the Bi-based precursor solution,presenting short-range ordered structures to a certain extent.The as-prepared BOC catalytic particles underwent the evolution process of initial Bi(OH)3 precipitate,early-stage formed KBiO_(2)molecules,intermediate amorphous(BiO)4CO3(OH)2 nanoparticles,and finally crystallized flower-like BOC particles self-assembled by nanosheets.The flower-like BOC particles,Bi/BOC composite,and Bi nanospheres were further prepared with different synthesis paths.Flower-like BOC particles showed the best photocatalytic degradation performance of RhB.Scavenger experiment and theoretical calculation revealed the photocatalytic mechanisms of BOC.This work has implications for path-dependent synthesis of other catalysts.
