Core-shell toughening particles are structured composite particles consisting of generally two different components, one at the center as a rubbery elastic core and surrounding by the second as a glassy inelastic shel...Core-shell toughening particles are structured composite particles consisting of generally two different components, one at the center as a rubbery elastic core and surrounding by the second as a glassy inelastic shell. The design, preparation, and application of core-shell polymer particles have been briefly reviewed. Morphological characteristics of the core-shell particles by transmission electron microscopy(TEM) and scanning electron microscopy(SEM) are focused. The vital factors that are useful to control core-shell morphology and toughening properties including core-shell monomer species, polymerization conditions, cross-linking reagents, synthetic method, and post-processing techniques are analyzed. Distinguished properties are mainly considered as the most desirable features that endow core-shell polymer particles with various applicabilities, particularly as effectively toughening components in brittle epoxy resin and polylactide that are substrate of copper clad laminate widely used in the modern electronic world and environmentally friendly materials that are useful as packaging films, disposable tableware, biomedical equipment, and new energy vehicles.展开更多
The rubber-containing waste materials have been widely used to improve the engineering properties of soils in recent years.Among others,granular rubbers are utilized in various ways to increase the bearing capacity an...The rubber-containing waste materials have been widely used to improve the engineering properties of soils in recent years.Among others,granular rubbers are utilized in various ways to increase the bearing capacity and shear strength and to reduce the settlement and liquefaction potential of soils.The granular rubbers have many advantages such as temperature resistance,flexibility,tear-resistance,non-slip,and thermal and electrical insulation.This study presents the distribution characteristics of five different types of clayey soils with different engineering properties containing waste rubber particles(WRPs).On the other hand,determining and controlling the dispersion characteristics of clayey soils is two significant engineering problems.The study aims to solve these two remarkable and problematic issues in an eco-friendly and safe way.The role of WRP treatment in the investigation of soil dispersion behavior,which can cause dangerous problems such as piping,erosion,and dispersion,reflects the original and different perspectives of this study.Within this scope,geotechnical parameters of the clayey soils were determined.Subsequently,pinhole test,crumb test,double hydrometer test,and scanning electron microscopy(SEM)analysis were performed on the Na-activated bentonite,refined ball clay,Ukrainian kaolin,Avanos kaolin,and Afyon clay samples with different percentages of WRPs(0%,5%,10%,and 15%).Consequently,Avanos and Ukrainian kaolin clays gave the most limited response to the dispersion behavior with the addition of WRP.Also,WRP treatment on the ball clay and bentonite samples showed limited efficiency.Afyon clay,which was defined as dispersive by the three tests that determined its dispersion potential,showed 3 level changes in the pinhole tests and 2 level changes in the crumb tests,and gave the most effective results in terms of WRP efficiency.展开更多
A kind of core(SBR)-shell(PS)particles was synthesized by using SBR latex and grafting with St under gammairradiation.The influences of absorbed dose and dose rate on the grafting yield of PS on SBR seed latex have be...A kind of core(SBR)-shell(PS)particles was synthesized by using SBR latex and grafting with St under gammairradiation.The influences of absorbed dose and dose rate on the grafting yield of PS on SBR seed latex have beeninvestigated.Results show there was a transition layer which contained the SBR/PS graft copolymer between the SBR coreand PS shell.Dynamic laser scattering(DLS)and differential scanning calorimetry(DSC)results confirm the existence ofgrafted polystyrene,and transmission electron microscope(TEM)observation verifies the core-shell structure of SBR-g-PSlatex.Such SBR/PS core-shell latex could be processed easily to ultrafine rubber powders by using spray drying andexpected to be used as an impact modifier for PS.展开更多
The miscibility,mechanical properties,morphology and toughening mechanism of PC/PBA-PMMA blends wereinvestigated.The dynamic mechanical results show that PC/PBA-PMMA blend has good miscibility and strong interfacialad...The miscibility,mechanical properties,morphology and toughening mechanism of PC/PBA-PMMA blends wereinvestigated.The dynamic mechanical results show that PC/PBA-PMMA blend has good miscibility and strong interfacialadhesion.The Izod impact strength of blend PC/PBA-PMMA with 4%(volume fraction)PBA-PMMA core-shell modifier is16 times higher than that of pure PC.The core-shell volume fraction and thickness of the PMMA shell have effect on thetoughness of PC/PBA-PMMA blends.As PMMA volume fraction increases,the toughness of PC/PBA-PMMA blendincreases,and reaches a maximum value at 30% volume fraction of PMMA or so.The tensile properties of PC/PBA-PMMAblend with a minimum amount of PBA-PMMA modifier show that brittle-tough transition has no significant variance incomparison with that of pure PC.The scanning electron microscopic(SEM)observation indicates that the tougheningmechanism of the blend with the pseudo-ductile matrix modified by small core-shell latex polymer particles is the synergeticeffect of cavitation and shear yielding of the matrix.展开更多
Mechanlcal properties of epoxy resin were investigated by adding core-shell elastic particles (CSEP). The results indicated that optimized core-shell ratio was 60/40 and the loading volume of CSEP was 10 phr (per hund...Mechanlcal properties of epoxy resin were investigated by adding core-shell elastic particles (CSEP). The results indicated that optimized core-shell ratio was 60/40 and the loading volume of CSEP was 10 phr (per hundred parts of epoxy resin by weight). The impact strength of modified systems increased apparently with the decrease of core sizes. However, the shearing strength changed gently with the particle sizes. CSEP with lightly crosslinked rubbery core showed more effectiveness on toughness than others. With solution blending, CSEP could be dispersed in epoxy matrix well, and the morphologies of dispersed rubber domains were controlled perfectly by CSEP whose structure was predesigned. A cavitation-shearing band toughness mechanism was observed from the SEM micrographs of fracture surface. It also was found that the deforming temperature (DT) of modified epoxy did not decline apparently.展开更多
PS/SiO2 particles with core-shell structure were synthesized by coating silica on surface of polystyrene(PS) colloidal particles.The reaction parameters,such as initial tetraethyl orthosilicate(TEOS) concentration,wat...PS/SiO2 particles with core-shell structure were synthesized by coating silica on surface of polystyrene(PS) colloidal particles.The reaction parameters,such as initial tetraethyl orthosilicate(TEOS) concentration,water concentration and reaction temperature,have been investigated to control the thickness of silica shells.The shell thickness was prepositional to the square root of the initial concentration of TEOS and first increased with increasing water concentration,reached a maximum at about 2.0 mol/L and then started decreasing beyond that concentration.It was also found that the shell thickness decreased firstly with the reaction temperature added,then tended to a constant.The so-synthesized PS/SiO2 core-shell particles were directly crystallized into 3-D ordered thin film,then sintered at 570℃ into the ordered macroporous thin film.Compared with the conditional method,the present approach avoids repeatedly filling the precursor in the templetes and save time more.展开更多
Methotrexate (MTX) is an antineoplastic drug, and due to its high toxicity, the therapeutic drug mon- itoring is strictly conducted in the clinical practice. The chemometric optimization and validation of a high per...Methotrexate (MTX) is an antineoplastic drug, and due to its high toxicity, the therapeutic drug mon- itoring is strictly conducted in the clinical practice. The chemometric optimization and validation of a high performance liquid chromatography (HPLC) method using core-shell particles is presented for the determination of MTX in plasma during therapeutic monitoring. Experimental design and response surface methodology (RSM) were applied for the optimization of the chromatographic system and the analyte extraction step. A Poroshel1120 EC-C18 (3.0 mm × 75 mm, 2.7 μm) column was used to obtain a fast and efficient separation in a complete run time of 4 min. The optimum conditions for the chroma- tographic system resulted in a mobile phase consisting of acetic acid/sodium acetate buffer solution (85.0 mM, pH =4.00) and 11.2% of acetonitrile at a flow rate of 0.4 mL/min. Selectivity, linearity, accuracy and precision were demonstrated in a range of 0.10-6.0 μM of MTX. The application of the optimized method required only 150μL of patient plasma and a low consumption of solvent to provide rapid re- sults.展开更多
To enhance the nucleation and crystallization properties of polyester (e.g., polyethylene terephthalate, PET), core-shell structured particles are used to improve these properties by controlling the inorganic di...To enhance the nucleation and crystallization properties of polyester (e.g., polyethylene terephthalate, PET), core-shell structured particles are used to improve these properties by controlling the inorganic dispersion properties in the polymers. In the paper, monodisperse particles of silica/polystyrene (PS) are prepared with both dispersion and emulsion polymerization techniques. The monodisperse silicon dioxide particles are first prepared with the seed growth method and modified by the coupling agents. Silica is properly modified with KH-570, and its size deviation is 3.0% or so. The modified silica then reacts with the mixture of ethanol, water medium, and monomer of styrene under dispersion polymerization. Results show that the dispersion polymerization technique is more suitable for monodisperse core-shell SiO2/PS particles than that of the emulsion. The morphology and molecular structure of the core-shell particles are investigated with the transmission electron microscope (TEM), and fourier transform infra-red spectroscopy (FTIR). The results show that the modified silica particles are successfully encapsulated with polystyrene. The average number of silica particles encapsulated into each polystyrene sphere decreases when the size of silica particles increases from 50 nm to 600 nm, and will approach one when the silica is greater than 380nm in size. The mass ratio for silica/PS particles in emulsion polymerization is 4.7/1, lower than that of 6.8/1 for dispersion polymerization, which is the first reported optimized data for preparing the similar monodisperse composite particles. Thus, the PS shell in the former is thinner than that in the latter.展开更多
The ZnO-Ag core-shell ultrafine particle in ethanol was prepared by photoreduction and colloidal methods. The experimental results obtained from aboorption spectroscopy. fluorescence sopectroscopy and electron microsc...The ZnO-Ag core-shell ultrafine particle in ethanol was prepared by photoreduction and colloidal methods. The experimental results obtained from aboorption spectroscopy. fluorescence sopectroscopy and electron microscopy revealed that the structure of the hybrid wide ig ZnO core covered with Ag shell. The thickness of the silver layer can ho controlled by the concentration of Ag+ ions and the time of UV irradiation. The structure of the electric double layer of the ZnO seed greatly affects the formation of ZnO-Ag hybtid particle.展开更多
The demand on low-carbon emission fabrication technologies for energy storage materials is increasing dramatically with the global interest on carbon neutrality.As a promising active material for metal-sulfur batterie...The demand on low-carbon emission fabrication technologies for energy storage materials is increasing dramatically with the global interest on carbon neutrality.As a promising active material for metal-sulfur batteries,sulfur is of great interest due to its high-energy-density and abundance.However,there is a lack of industry-friendly and low-carbon fabrication strategies for high-performance sulfur-based active particles,which,however,is in critical need by their practical success.Herein,based on a hail-inspired sulfur nano-storm(HSN)technology developed in our lab,we report an energy-saving,solvent-free strategy for producing core-shell sulfur/carbon electrode particles(CNT@AC-S)in minutes.The fabrication of the CNT@AC-S electrode particles only involves low-cost sulfur blocks,commercial carbon nanotubes(CNT)and activated carbon(AC)micro-particles with high specific surface area.Based on the above core-shell CNT@AC-S particles,sulfur cathode with a high sulfur-loading of 9.2 mg cm^(-2) delivers a stable area capacity of 6.6 mAh cm^(-2) over 100 cycles.Furthermore,even for sulfur cathode with a super-high sulfur content(72 wt%over the whole electrode),it still delivers a high area capacity of 9 mAh cm^(-2) over50 cycles in a quasi-lean electrolyte condition.In a nutshell,this study brings a green and industryfriendly fabrication strategy for cost-effective production of rationally designed S-rich electrode particles.展开更多
According to the present theories of plastic toughening, it is impossible to enhance the toughness, stiffness and/orheat resistance of plastics simultaneously by using rubber. A series of novel nano-rubber particles (...According to the present theories of plastic toughening, it is impossible to enhance the toughness, stiffness and/orheat resistance of plastics simultaneously by using rubber. A series of novel nano-rubber particles (UFPR) were introduced,which were prepared through irradiating common rubber lattices and spray drying them. Epoxies toughened with UFPRshowed a much better toughening effect than those with CTBN, and the heat resistance of epoxy was unexpectedly elevated.For polypropylene toughening, UFPR can improve the toughness, stiffness and heat resistance of PP simultaneously. Thesespecial toughening effects overcome the deficiencies in rubber toughening technology and are worth further investigating.展开更多
The dispersion of nanoparticles plays a key role in enhancing the mechanical performance of polymer nanocomposites.In this work,one hybrid epoxy nanocomposite reinforced by a well dispersed,zinc oxide functionalized,m...The dispersion of nanoparticles plays a key role in enhancing the mechanical performance of polymer nanocomposites.In this work,one hybrid epoxy nanocomposite reinforced by a well dispersed,zinc oxide functionalized,multi-wall carbon nanotube (Zn O-MWCNT) and core-shell rubber (CSR) was prepared,which possesses both high modulus and fracture toughness while maintaining relatively high glass transition temperature (Tg).The improved fracture toughness from 0.82 MPa mfor neat epoxy to 1.46 MPa mfor the ternary epoxy nanocomposites is resulted from a series of synergistic toughening mechanisms,including cavitation of CSR-induced matrix shear banding,along with the fracture of MWCNTs and crack deflection.The implication of the present study for the preparation of high-performance polymer nanocomposites is discussed.展开更多
Two highly cross-linked superfine styrene-butadiene rubber particles, one with 1 wt% of carboxyl groups and theother without such groups having particle sizes of 130-150 nm and 80-100 nm respectively, were used to pre...Two highly cross-linked superfine styrene-butadiene rubber particles, one with 1 wt% of carboxyl groups and theother without such groups having particle sizes of 130-150 nm and 80-100 nm respectively, were used to prepare nylon6/rubber composites via in situ polymerization. It was found that carboxylic styrene-butadiene dispersed uniformly in nylonmatrix and there was strong interfacial interaction because of the graft polymer formed by the reaction of nylon with carboxylgroup of the rubber, resulting in considerably improved impact strength with almost unchanged tensile strength. However,the addition of styrene-butadiene without carboxyl groups showed intensive agglomeration of the rubber particles and weakinterfacial interactions, and the toughness of the materials was improved slightly. The crystallization and rheological behavior of the composites were also discussed.展开更多
Natural aluminum particles have the core-shell structure.The structure response refers to the mechanical behavior of the aluminum particle structure caused by external influences.The dynamic behavior of the structural...Natural aluminum particles have the core-shell structure.The structure response refers to the mechanical behavior of the aluminum particle structure caused by external influences.The dynamic behavior of the structural response of aluminum core-shell particles before combustion is of great importance for the aluminum powder burning mechanism and its applications.In this paper,an aluminum particle combustion experiment in a detonation environment is conducted and analyzed;the breakage factors of aluminum particles shell in detonation environment are analyzed.The experiment results show that the aluminum particle burns in a gaseous state and condenses into a sub-micron particle cluster.The calculation and simulation demonstrate that the rupture of aluminum particle shell in the detonation environment is mainly caused by the impact of the detonation wave.The detonation wave impacts the aluminum particles,resulting in shell cracking,and due to the shrinkage-expansion of the aluminum core and stripping of the detonation product,the cracked shell is fractured and peeled with the aluminum reacting with the detonation product.展开更多
A new kind of inelastomer impact modifier with a coreshell structure was synthesized by employing a multistep composite emulsion polymerization technique, the size and morphology structure of the coreshell particles c...A new kind of inelastomer impact modifier with a coreshell structure was synthesized by employing a multistep composite emulsion polymerization technique, the size and morphology structure of the coreshell particles could be controlled by the multistep composite emulsion polymerization technique. The study of the impact strength and the elongation at break of the PVC/CPE blend with different contents of coreshell particles(CS) indicated that the mechanical properties of PVC/CPE/CS composite were the best when the concentration of the particle was 25%(mass fraction) which showed the different regularities and characteristics of elastomer toughening plastic.展开更多
The PAn-PEO-PAn triblock copolymer with the PEG chain length of 400 was synthesized by chemical oxidation copolymerization of aniline and α,ω-bis(p-aminophenyl)poly(ethylene glycol)and characterized by FT-IR and...The PAn-PEO-PAn triblock copolymer with the PEG chain length of 400 was synthesized by chemical oxidation copolymerization of aniline and α,ω-bis(p-aminophenyl)poly(ethylene glycol)and characterized by FT-IR and TEM.The experimental results show that the copolymer particles are of μtypical core-shell structure after the self-assembly process in water.Its conductivity is much lower than that of the pure PAn.The suspension containing 20 vol% PAn-PEO-PAn tiblock copolymer in silicone oil exhibits.a typical electrorheological (ER) effect in DC electric field.while it shows a lower leakage current density than that of the pure PAn-based ER fluids.Therefore,the PEO shell hinders the electric hop among PANI chains and decreases the current density of ER fluids in an external electric field.at the same time the interface polarity improves the ER effects.展开更多
This paper discusses the utilization of nano-sized fillers in Polyamide 6 to increase the fracture resistance of the composites, which are crucial for various engineering applications. The toughening of the composites...This paper discusses the utilization of nano-sized fillers in Polyamide 6 to increase the fracture resistance of the composites, which are crucial for various engineering applications. The toughening of the composites is achieved by using dispersed nano-scaled rubber particles (Polyether block copolymer) as the inclusion in Polyamide 6 matrix. For a better understanding of the mechanical behavior of the composites, it is indispensable to use analytical and numerical models for evaluating the overall mechanical behavior and damage mechanism of the composite. In this work the toughening mechanism is studied through literature review and by analytical modeling. The mechanical behavior of the composites such as elastic plastic and damage properties are calculated numerically with 3D representative volume element (RVE) models. The numerical results are compared with previously obtained experiments. The influence of volume fraction and aspect ratio of inclusions on the macroscopic stress strain curve as well as the size effect of inclusions and also the failure properties of the composite are studied in detail.展开更多
基金Sponsored by the National Natural Science Foundation of China (Grant No.52173011)。
文摘Core-shell toughening particles are structured composite particles consisting of generally two different components, one at the center as a rubbery elastic core and surrounding by the second as a glassy inelastic shell. The design, preparation, and application of core-shell polymer particles have been briefly reviewed. Morphological characteristics of the core-shell particles by transmission electron microscopy(TEM) and scanning electron microscopy(SEM) are focused. The vital factors that are useful to control core-shell morphology and toughening properties including core-shell monomer species, polymerization conditions, cross-linking reagents, synthetic method, and post-processing techniques are analyzed. Distinguished properties are mainly considered as the most desirable features that endow core-shell polymer particles with various applicabilities, particularly as effectively toughening components in brittle epoxy resin and polylactide that are substrate of copper clad laminate widely used in the modern electronic world and environmentally friendly materials that are useful as packaging films, disposable tableware, biomedical equipment, and new energy vehicles.
基金supported by the Scientific Research Project of Aksaray University(Grant No.BAP-2021-31).
文摘The rubber-containing waste materials have been widely used to improve the engineering properties of soils in recent years.Among others,granular rubbers are utilized in various ways to increase the bearing capacity and shear strength and to reduce the settlement and liquefaction potential of soils.The granular rubbers have many advantages such as temperature resistance,flexibility,tear-resistance,non-slip,and thermal and electrical insulation.This study presents the distribution characteristics of five different types of clayey soils with different engineering properties containing waste rubber particles(WRPs).On the other hand,determining and controlling the dispersion characteristics of clayey soils is two significant engineering problems.The study aims to solve these two remarkable and problematic issues in an eco-friendly and safe way.The role of WRP treatment in the investigation of soil dispersion behavior,which can cause dangerous problems such as piping,erosion,and dispersion,reflects the original and different perspectives of this study.Within this scope,geotechnical parameters of the clayey soils were determined.Subsequently,pinhole test,crumb test,double hydrometer test,and scanning electron microscopy(SEM)analysis were performed on the Na-activated bentonite,refined ball clay,Ukrainian kaolin,Avanos kaolin,and Afyon clay samples with different percentages of WRPs(0%,5%,10%,and 15%).Consequently,Avanos and Ukrainian kaolin clays gave the most limited response to the dispersion behavior with the addition of WRP.Also,WRP treatment on the ball clay and bentonite samples showed limited efficiency.Afyon clay,which was defined as dispersive by the three tests that determined its dispersion potential,showed 3 level changes in the pinhole tests and 2 level changes in the crumb tests,and gave the most effective results in terms of WRP efficiency.
基金This work was supported by the National High Technology ResearchDevelopment Program of China(863 Program)(No.2002AA302510).
文摘A kind of core(SBR)-shell(PS)particles was synthesized by using SBR latex and grafting with St under gammairradiation.The influences of absorbed dose and dose rate on the grafting yield of PS on SBR seed latex have beeninvestigated.Results show there was a transition layer which contained the SBR/PS graft copolymer between the SBR coreand PS shell.Dynamic laser scattering(DLS)and differential scanning calorimetry(DSC)results confirm the existence ofgrafted polystyrene,and transmission electron microscope(TEM)observation verifies the core-shell structure of SBR-g-PSlatex.Such SBR/PS core-shell latex could be processed easily to ultrafine rubber powders by using spray drying andexpected to be used as an impact modifier for PS.
基金This work was supported by the National Natural Science Foundation of China(Nos.5030301750373044+8 种基金50253002500730242007403720490220503900905002700120023003)the Special Funds for Major State Basic Research Projects(No.2003CB615600)the Chi
文摘The miscibility,mechanical properties,morphology and toughening mechanism of PC/PBA-PMMA blends wereinvestigated.The dynamic mechanical results show that PC/PBA-PMMA blend has good miscibility and strong interfacialadhesion.The Izod impact strength of blend PC/PBA-PMMA with 4%(volume fraction)PBA-PMMA core-shell modifier is16 times higher than that of pure PC.The core-shell volume fraction and thickness of the PMMA shell have effect on thetoughness of PC/PBA-PMMA blends.As PMMA volume fraction increases,the toughness of PC/PBA-PMMA blendincreases,and reaches a maximum value at 30% volume fraction of PMMA or so.The tensile properties of PC/PBA-PMMAblend with a minimum amount of PBA-PMMA modifier show that brittle-tough transition has no significant variance incomparison with that of pure PC.The scanning electron microscopic(SEM)observation indicates that the tougheningmechanism of the blend with the pseudo-ductile matrix modified by small core-shell latex polymer particles is the synergeticeffect of cavitation and shear yielding of the matrix.
文摘Mechanlcal properties of epoxy resin were investigated by adding core-shell elastic particles (CSEP). The results indicated that optimized core-shell ratio was 60/40 and the loading volume of CSEP was 10 phr (per hundred parts of epoxy resin by weight). The impact strength of modified systems increased apparently with the decrease of core sizes. However, the shearing strength changed gently with the particle sizes. CSEP with lightly crosslinked rubbery core showed more effectiveness on toughness than others. With solution blending, CSEP could be dispersed in epoxy matrix well, and the morphologies of dispersed rubber domains were controlled perfectly by CSEP whose structure was predesigned. A cavitation-shearing band toughness mechanism was observed from the SEM micrographs of fracture surface. It also was found that the deforming temperature (DT) of modified epoxy did not decline apparently.
基金Supported by the National Natural Science Foundation of China(No.:20221603)
文摘PS/SiO2 particles with core-shell structure were synthesized by coating silica on surface of polystyrene(PS) colloidal particles.The reaction parameters,such as initial tetraethyl orthosilicate(TEOS) concentration,water concentration and reaction temperature,have been investigated to control the thickness of silica shells.The shell thickness was prepositional to the square root of the initial concentration of TEOS and first increased with increasing water concentration,reached a maximum at about 2.0 mol/L and then started decreasing beyond that concentration.It was also found that the shell thickness decreased firstly with the reaction temperature added,then tended to a constant.The so-synthesized PS/SiO2 core-shell particles were directly crystallized into 3-D ordered thin film,then sintered at 570℃ into the ordered macroporous thin film.Compared with the conditional method,the present approach avoids repeatedly filling the precursor in the templetes and save time more.
基金Universidad Nacional del Litoral (Project CAI+D 2011 No. PI-50120110100025 LI)
文摘Methotrexate (MTX) is an antineoplastic drug, and due to its high toxicity, the therapeutic drug mon- itoring is strictly conducted in the clinical practice. The chemometric optimization and validation of a high performance liquid chromatography (HPLC) method using core-shell particles is presented for the determination of MTX in plasma during therapeutic monitoring. Experimental design and response surface methodology (RSM) were applied for the optimization of the chromatographic system and the analyte extraction step. A Poroshel1120 EC-C18 (3.0 mm × 75 mm, 2.7 μm) column was used to obtain a fast and efficient separation in a complete run time of 4 min. The optimum conditions for the chroma- tographic system resulted in a mobile phase consisting of acetic acid/sodium acetate buffer solution (85.0 mM, pH =4.00) and 11.2% of acetonitrile at a flow rate of 0.4 mL/min. Selectivity, linearity, accuracy and precision were demonstrated in a range of 0.10-6.0 μM of MTX. The application of the optimized method required only 150μL of patient plasma and a low consumption of solvent to provide rapid re- sults.
文摘To enhance the nucleation and crystallization properties of polyester (e.g., polyethylene terephthalate, PET), core-shell structured particles are used to improve these properties by controlling the inorganic dispersion properties in the polymers. In the paper, monodisperse particles of silica/polystyrene (PS) are prepared with both dispersion and emulsion polymerization techniques. The monodisperse silicon dioxide particles are first prepared with the seed growth method and modified by the coupling agents. Silica is properly modified with KH-570, and its size deviation is 3.0% or so. The modified silica then reacts with the mixture of ethanol, water medium, and monomer of styrene under dispersion polymerization. Results show that the dispersion polymerization technique is more suitable for monodisperse core-shell SiO2/PS particles than that of the emulsion. The morphology and molecular structure of the core-shell particles are investigated with the transmission electron microscope (TEM), and fourier transform infra-red spectroscopy (FTIR). The results show that the modified silica particles are successfully encapsulated with polystyrene. The average number of silica particles encapsulated into each polystyrene sphere decreases when the size of silica particles increases from 50 nm to 600 nm, and will approach one when the silica is greater than 380nm in size. The mass ratio for silica/PS particles in emulsion polymerization is 4.7/1, lower than that of 6.8/1 for dispersion polymerization, which is the first reported optimized data for preparing the similar monodisperse composite particles. Thus, the PS shell in the former is thinner than that in the latter.
文摘The ZnO-Ag core-shell ultrafine particle in ethanol was prepared by photoreduction and colloidal methods. The experimental results obtained from aboorption spectroscopy. fluorescence sopectroscopy and electron microscopy revealed that the structure of the hybrid wide ig ZnO core covered with Ag shell. The thickness of the silver layer can ho controlled by the concentration of Ag+ ions and the time of UV irradiation. The structure of the electric double layer of the ZnO seed greatly affects the formation of ZnO-Ag hybtid particle.
基金supported by the Double First-Class Construction Funds of Sichuan University and National Natural Science Foundation of China(NNSFC)financial support from the National Science Foundation of China(51873126,51422305,51721091)。
文摘The demand on low-carbon emission fabrication technologies for energy storage materials is increasing dramatically with the global interest on carbon neutrality.As a promising active material for metal-sulfur batteries,sulfur is of great interest due to its high-energy-density and abundance.However,there is a lack of industry-friendly and low-carbon fabrication strategies for high-performance sulfur-based active particles,which,however,is in critical need by their practical success.Herein,based on a hail-inspired sulfur nano-storm(HSN)technology developed in our lab,we report an energy-saving,solvent-free strategy for producing core-shell sulfur/carbon electrode particles(CNT@AC-S)in minutes.The fabrication of the CNT@AC-S electrode particles only involves low-cost sulfur blocks,commercial carbon nanotubes(CNT)and activated carbon(AC)micro-particles with high specific surface area.Based on the above core-shell CNT@AC-S particles,sulfur cathode with a high sulfur-loading of 9.2 mg cm^(-2) delivers a stable area capacity of 6.6 mAh cm^(-2) over 100 cycles.Furthermore,even for sulfur cathode with a super-high sulfur content(72 wt%over the whole electrode),it still delivers a high area capacity of 9 mAh cm^(-2) over50 cycles in a quasi-lean electrolyte condition.In a nutshell,this study brings a green and industryfriendly fabrication strategy for cost-effective production of rationally designed S-rich electrode particles.
基金This work was financially supported by the Special Funds for Major State Basic Research Projects of China (No. G1999064800).
文摘According to the present theories of plastic toughening, it is impossible to enhance the toughness, stiffness and/orheat resistance of plastics simultaneously by using rubber. A series of novel nano-rubber particles (UFPR) were introduced,which were prepared through irradiating common rubber lattices and spray drying them. Epoxies toughened with UFPRshowed a much better toughening effect than those with CTBN, and the heat resistance of epoxy was unexpectedly elevated.For polypropylene toughening, UFPR can improve the toughness, stiffness and heat resistance of PP simultaneously. Thesespecial toughening effects overcome the deficiencies in rubber toughening technology and are worth further investigating.
基金the KANEKA Corporation for their financial support。
文摘The dispersion of nanoparticles plays a key role in enhancing the mechanical performance of polymer nanocomposites.In this work,one hybrid epoxy nanocomposite reinforced by a well dispersed,zinc oxide functionalized,multi-wall carbon nanotube (Zn O-MWCNT) and core-shell rubber (CSR) was prepared,which possesses both high modulus and fracture toughness while maintaining relatively high glass transition temperature (Tg).The improved fracture toughness from 0.82 MPa mfor neat epoxy to 1.46 MPa mfor the ternary epoxy nanocomposites is resulted from a series of synergistic toughening mechanisms,including cavitation of CSR-induced matrix shear banding,along with the fracture of MWCNTs and crack deflection.The implication of the present study for the preparation of high-performance polymer nanocomposites is discussed.
文摘Two highly cross-linked superfine styrene-butadiene rubber particles, one with 1 wt% of carboxyl groups and theother without such groups having particle sizes of 130-150 nm and 80-100 nm respectively, were used to prepare nylon6/rubber composites via in situ polymerization. It was found that carboxylic styrene-butadiene dispersed uniformly in nylonmatrix and there was strong interfacial interaction because of the graft polymer formed by the reaction of nylon with carboxylgroup of the rubber, resulting in considerably improved impact strength with almost unchanged tensile strength. However,the addition of styrene-butadiene without carboxyl groups showed intensive agglomeration of the rubber particles and weakinterfacial interactions, and the toughness of the materials was improved slightly. The crystallization and rheological behavior of the composites were also discussed.
基金Project supported by the National Natural Science Foundation of China(Grant No.11772058)
文摘Natural aluminum particles have the core-shell structure.The structure response refers to the mechanical behavior of the aluminum particle structure caused by external influences.The dynamic behavior of the structural response of aluminum core-shell particles before combustion is of great importance for the aluminum powder burning mechanism and its applications.In this paper,an aluminum particle combustion experiment in a detonation environment is conducted and analyzed;the breakage factors of aluminum particles shell in detonation environment are analyzed.The experiment results show that the aluminum particle burns in a gaseous state and condenses into a sub-micron particle cluster.The calculation and simulation demonstrate that the rupture of aluminum particle shell in the detonation environment is mainly caused by the impact of the detonation wave.The detonation wave impacts the aluminum particles,resulting in shell cracking,and due to the shrinkage-expansion of the aluminum core and stripping of the detonation product,the cracked shell is fractured and peeled with the aluminum reacting with the detonation product.
文摘A new kind of inelastomer impact modifier with a coreshell structure was synthesized by employing a multistep composite emulsion polymerization technique, the size and morphology structure of the coreshell particles could be controlled by the multistep composite emulsion polymerization technique. The study of the impact strength and the elongation at break of the PVC/CPE blend with different contents of coreshell particles(CS) indicated that the mechanical properties of PVC/CPE/CS composite were the best when the concentration of the particle was 25%(mass fraction) which showed the different regularities and characteristics of elastomer toughening plastic.
文摘The PAn-PEO-PAn triblock copolymer with the PEG chain length of 400 was synthesized by chemical oxidation copolymerization of aniline and α,ω-bis(p-aminophenyl)poly(ethylene glycol)and characterized by FT-IR and TEM.The experimental results show that the copolymer particles are of μtypical core-shell structure after the self-assembly process in water.Its conductivity is much lower than that of the pure PAn.The suspension containing 20 vol% PAn-PEO-PAn tiblock copolymer in silicone oil exhibits.a typical electrorheological (ER) effect in DC electric field.while it shows a lower leakage current density than that of the pure PAn-based ER fluids.Therefore,the PEO shell hinders the electric hop among PANI chains and decreases the current density of ER fluids in an external electric field.at the same time the interface polarity improves the ER effects.
文摘This paper discusses the utilization of nano-sized fillers in Polyamide 6 to increase the fracture resistance of the composites, which are crucial for various engineering applications. The toughening of the composites is achieved by using dispersed nano-scaled rubber particles (Polyether block copolymer) as the inclusion in Polyamide 6 matrix. For a better understanding of the mechanical behavior of the composites, it is indispensable to use analytical and numerical models for evaluating the overall mechanical behavior and damage mechanism of the composite. In this work the toughening mechanism is studied through literature review and by analytical modeling. The mechanical behavior of the composites such as elastic plastic and damage properties are calculated numerically with 3D representative volume element (RVE) models. The numerical results are compared with previously obtained experiments. The influence of volume fraction and aspect ratio of inclusions on the macroscopic stress strain curve as well as the size effect of inclusions and also the failure properties of the composite are studied in detail.