The compacted TiAl alloys were prepared and the effects of HIPing time on their properties were studied. At 1100 ℃, 80 Mpa, the density of TiAl alloy reached up to 3.46 g/cm3 after 10 min HIPing. The densities of TiA...The compacted TiAl alloys were prepared and the effects of HIPing time on their properties were studied. At 1100 ℃, 80 Mpa, the density of TiAl alloy reached up to 3.46 g/cm3 after 10 min HIPing. The densities of TiAl alloys did not significantly increase with the time increasing from 10 min to 70 min. Under the experimental conditions, the TiAl alloys obtained is an unstable state alloy, and the effect of HIPing time on the TiAl phase is not significant. The micro-cracks appear in inner of TiAl alloy with the HIPing time increase. At 1380 ℃, after one hour heat treatment, the micro-cracks disappear and the phase changes into stable state and its microstructure changs into lamella.展开更多
This study aims to examine the effect of replacing vanadium by niobium and iron on the tribological behavior of hot-isostatic-pressed titanium alloy （Ti-6Al-4V） biomaterial, using a ball-on-disk-type oscillating tri...This study aims to examine the effect of replacing vanadium by niobium and iron on the tribological behavior of hot-isostatic-pressed titanium alloy （Ti-6Al-4V） biomaterial, using a ball-on-disk-type oscillating tribometer, under wet conditions using physiological solution in accordance with the ISO7148 standards. The tests were carried out under a normal load of 6 N, with an AISI 52100 grade steel ball as a counter face. The morphological changes and structural evolution of the nanoparticle powders using different milling times （2, 6, 12 and 18 h） were studied. The morphological characterization indicated that the particle and crystallite size continuously decrease with increasing milling time to reach the lowest value of 4 nm at 18-h milling. The friction coefficient and wear rate were lower in the samples milled at 18 h （0.226, 0.297 and 0.423; and 0.66 × 10-2, 0.87 × 10-2 and 1.51 × 10-2 μm3 N-1 i, tm-1） for Ti-6Al-4Fe, Ti-6A1-7Nb and Ti-6Al-4V, respectively. This improvement in friction and wear resistance is attributed to the grain refinement at 18-h milling. The Ti-6Al-4Fe samples showed good tribological performance for all milling times.展开更多
The phenomenon of adsorption of solid particles at fluid interfaces to stabilize emulsions or foams have been known for more than a century.Today,particle-stabilized emulsions,often referred to as Pickering emulsions,...The phenomenon of adsorption of solid particles at fluid interfaces to stabilize emulsions or foams have been known for more than a century.Today,particle-stabilized emulsions,often referred to as Pickering emulsions,are receiving growing attention as they are encountered in oil recovery and have long been used in personal care products and food industry.Over the past 10 years the focus of the Pickering emulsion has also increasingly shifted to biomedical applications with thanks to novel syntheses of a wide range of biocompatible particle stabilizers.Here,a brief overview of the development of biocompatible particles is given for Pickering emulsion stabilization,including alginate,poly(lactic-co-gIycolic acid)(PLGA),and protein-based particles.The materials prepared by templating from emulsion stabilized with biocompatible particles include colloidal capsules and hierarchically porous materials.It is hoped that the understanding gained from the recent intense activity in the field will enable more researchers to modify existing materials and design new formulations,which would be beneficial for exploring more biological applications.展开更多
As promising engineering materials for green and sustainable processes, porous metalorganic framework(MOF)-polymer composites show great potential in applications, including adsorption, separation, catalysis, and bioe...As promising engineering materials for green and sustainable processes, porous metalorganic framework(MOF)-polymer composites show great potential in applications, including adsorption, separation, catalysis, and bioengineering. Owing to the mild and scalable operation, porous polymeric materials derived from high internal phase emulsion templates(polyHIPE) have received great interests in recent decades. In this contribution, research progress of the preparation of porous MOF@polyHIPE composites and their applications are reviewed, highlighting how can MOF particles be shaped by HIPE templates, in particular the polymerizable ones. Four different emulsion templates stabilized by MOFs and the applications of corresponding MOF@polyHIPE are included. Hopefully,both the state-of-art and future directions present herein can give rise to the development of highperformance porous MOF@polyHIPEs.展开更多
Flexible shape-memory polymers were synthesized by Pickering high internal phase emulsion(HIPE)polymerization and used to adsorb and separate tetrodotoxin(TTX)from an aqueous solution.SiO_(2)nanoparticles were used to...Flexible shape-memory polymers were synthesized by Pickering high internal phase emulsion(HIPE)polymerization and used to adsorb and separate tetrodotoxin(TTX)from an aqueous solution.SiO_(2)nanoparticles were used to stabilize the Pickering oil-in-water(O/W)HIPEs.We introduced imidazolium-modified bromobutyl rubber(IBR)with excellent mechanical properties and high viscosity into the emulsion system as the shape-memory monomer.The properties,such as shape memory and morphology,were characterized by various methods,and batches of static adsorption experiments were conducted to analyze the adsorption performance of SiO_(2)@IBR on TTX.The characterization revealed that the SiO_(2)@IBR had a porous structure and good shape memory.Thus,the combination of SiO_(2)particles and IBR prevented shedding of SiO_(2)and enhanced the mechanical and adsorption properties of SiO_(2)@IBR.The results of the adsorption experiments indicated that the SiO_(2)@IBR had good adsorption of TTX.Both the Langmuir and Freundlich models fitted the isothermal adsorption experiment process.The TTX adsorption capacity of SiO_(2)@IBR was about 290.44 mg/g at 308 K.The fitting results of the pseudo-first-order and pseudosecond-order kinetic models showed that the adsorption process involved both chemical bonding and physical adsorption.After 10 adsorption and desorption experiments,the adsorption capacity of SiO_(2)@IBR decreased less than 0.03%,indicating that it had good adsorption and regeneration performance.展开更多
文摘The compacted TiAl alloys were prepared and the effects of HIPing time on their properties were studied. At 1100 ℃, 80 Mpa, the density of TiAl alloy reached up to 3.46 g/cm3 after 10 min HIPing. The densities of TiAl alloys did not significantly increase with the time increasing from 10 min to 70 min. Under the experimental conditions, the TiAl alloys obtained is an unstable state alloy, and the effect of HIPing time on the TiAl phase is not significant. The micro-cracks appear in inner of TiAl alloy with the HIPing time increase. At 1380 ℃, after one hour heat treatment, the micro-cracks disappear and the phase changes into stable state and its microstructure changs into lamella.
文摘This study aims to examine the effect of replacing vanadium by niobium and iron on the tribological behavior of hot-isostatic-pressed titanium alloy （Ti-6Al-4V） biomaterial, using a ball-on-disk-type oscillating tribometer, under wet conditions using physiological solution in accordance with the ISO7148 standards. The tests were carried out under a normal load of 6 N, with an AISI 52100 grade steel ball as a counter face. The morphological changes and structural evolution of the nanoparticle powders using different milling times （2, 6, 12 and 18 h） were studied. The morphological characterization indicated that the particle and crystallite size continuously decrease with increasing milling time to reach the lowest value of 4 nm at 18-h milling. The friction coefficient and wear rate were lower in the samples milled at 18 h （0.226, 0.297 and 0.423; and 0.66 × 10-2, 0.87 × 10-2 and 1.51 × 10-2 μm3 N-1 i, tm-1） for Ti-6Al-4Fe, Ti-6A1-7Nb and Ti-6Al-4V, respectively. This improvement in friction and wear resistance is attributed to the grain refinement at 18-h milling. The Ti-6Al-4Fe samples showed good tribological performance for all milling times.
基金supported by the Hong Kong Scholars Pro gram(No.XJ2019048)China Postdoctoral Science Foundation funded project(No.2019T120950)+1 种基金financial support from the International Cooperation Project of the Chinese Academy of Science(No.122111KYSB20180021)Hong Kong Special Administration Region General Research Fund(No.CUHK14306617 and 2130535).
文摘The phenomenon of adsorption of solid particles at fluid interfaces to stabilize emulsions or foams have been known for more than a century.Today,particle-stabilized emulsions,often referred to as Pickering emulsions,are receiving growing attention as they are encountered in oil recovery and have long been used in personal care products and food industry.Over the past 10 years the focus of the Pickering emulsion has also increasingly shifted to biomedical applications with thanks to novel syntheses of a wide range of biocompatible particle stabilizers.Here,a brief overview of the development of biocompatible particles is given for Pickering emulsion stabilization,including alginate,poly(lactic-co-gIycolic acid)(PLGA),and protein-based particles.The materials prepared by templating from emulsion stabilized with biocompatible particles include colloidal capsules and hierarchically porous materials.It is hoped that the understanding gained from the recent intense activity in the field will enable more researchers to modify existing materials and design new formulations,which would be beneficial for exploring more biological applications.
基金supported by the National Natural Science Foundation of China (21808140, 21978089)Shanghai Rising-Star Program (22QA1402800)the Fundamental Research Funds for the Central Universities
文摘As promising engineering materials for green and sustainable processes, porous metalorganic framework(MOF)-polymer composites show great potential in applications, including adsorption, separation, catalysis, and bioengineering. Owing to the mild and scalable operation, porous polymeric materials derived from high internal phase emulsion templates(polyHIPE) have received great interests in recent decades. In this contribution, research progress of the preparation of porous MOF@polyHIPE composites and their applications are reviewed, highlighting how can MOF particles be shaped by HIPE templates, in particular the polymerizable ones. Four different emulsion templates stabilized by MOFs and the applications of corresponding MOF@polyHIPE are included. Hopefully,both the state-of-art and future directions present herein can give rise to the development of highperformance porous MOF@polyHIPEs.
基金Project supported by the National Natural Science Foundation of China(No.21878026)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX19_1798)+1 种基金the Jiangsu Province University Blue Projectthe Project of Higher Education Reform in Jiangsu Province(No.2019JSJG022),China。
文摘Flexible shape-memory polymers were synthesized by Pickering high internal phase emulsion(HIPE)polymerization and used to adsorb and separate tetrodotoxin(TTX)from an aqueous solution.SiO_(2)nanoparticles were used to stabilize the Pickering oil-in-water(O/W)HIPEs.We introduced imidazolium-modified bromobutyl rubber(IBR)with excellent mechanical properties and high viscosity into the emulsion system as the shape-memory monomer.The properties,such as shape memory and morphology,were characterized by various methods,and batches of static adsorption experiments were conducted to analyze the adsorption performance of SiO_(2)@IBR on TTX.The characterization revealed that the SiO_(2)@IBR had a porous structure and good shape memory.Thus,the combination of SiO_(2)particles and IBR prevented shedding of SiO_(2)and enhanced the mechanical and adsorption properties of SiO_(2)@IBR.The results of the adsorption experiments indicated that the SiO_(2)@IBR had good adsorption of TTX.Both the Langmuir and Freundlich models fitted the isothermal adsorption experiment process.The TTX adsorption capacity of SiO_(2)@IBR was about 290.44 mg/g at 308 K.The fitting results of the pseudo-first-order and pseudosecond-order kinetic models showed that the adsorption process involved both chemical bonding and physical adsorption.After 10 adsorption and desorption experiments,the adsorption capacity of SiO_(2)@IBR decreased less than 0.03%,indicating that it had good adsorption and regeneration performance.
