最新刊期
卷 ， 期 12 ， 2012
- 摘要：Electrorheological (ER) smart fluids can rapidly and reversibly response to an external electric field by transmitting rheological properties,which have many potential technical applications.However,conventional ER fluids based on microparticles are subjected to challenges in practical applications due to the problems including large particle sedimentation and low electric-field-induced yield strength.Recent researches of using nanoparticles as the dispersal phase have led to new interest in the development of non-conventional ER fluids with improved electrorheology.In this brief review,we especially focus on the recent researches on preparation,structure and electrorheology of two-dimensional graphene-based composites including graphene/semiconduting polymer graphene/polar polymer and graphene/carbonaceous composites.The results have showed that using graphene as host to prepare novel two-dimensional ER materials possibly provide a potential approach to develop high-performance ER fluids due to the advantages of the atomically thick two-dimensional structure,excellently electric and thermal properties.关键词：Electrorheology;Graphene;Nanocomposites
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发布时间：2021-03-19
Reviews
- 摘要：Tensile and anti-UV aging properties of polyvinylidene fluoride (PVDF)/polymethyl methacrylate (PMMA) blends prepared by melting compounding were investigated.The results indicated that PVDF had a good miscibility with little PMMA (10 wt%) so that the blend was homogeneous and had the best tensile properties and weatherability.On the other hand,significant phase separation occurred in the blends containing more than 20 wt% PMMA,which led to marked reductions in tensile properties and weatherability.PMMA played a role of diluent that accelerated molecular movements and reduced relaxation time of the blend.Because of the habit of PVDF tending to self-entangle in the blends,improving molecular motion at high temperatures could lead to the occurrence of phase separation.The binodal temperature of blends was got by the small amplitude temperature scanning experiment,which decreased with increasing PMMA content.The results did not follow some previous researches on solution casting blends.Crystallinity of PVDF increased and melting point decreased with increasing PMMA content.However,XRD results indicated that PMMA did not change the crystal structure of PVDF.Furthermore,TGA tests revealed that there was no synergistic effect between thermal decompositions of PMMA and PVDF in the blends.关键词：Blend;Phase separation;Properties;Rheology
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发布时间：2021-03-19 - 摘要：The electrical and rheological percolations in the emPP/HDPE/CB ternary composites are reported.The CB particles are selectively located in the HDPE phase.The HDPE/CB phase is conductive with 20 wt% CB.When the contents of HDPE/CB phase in the matrix of emPP increases,the conductive and rheological networks of the emPP/HDPE/CB ternary composites can be found.The results show that the electrical percolation appears when the HDPE/CB content reaches 20 wt%,and the percolation content of the HDPE/CB phase in the emPP matrix is 30 wt% obtained by dynamic rheology.The loss tangent does not show a peak in the frequency sweep until the HDPE/CB phase becomes a continuous phase in the material.This finding indicates that the role of loss tangent peak is not able to give enough information about the formation of the filler network in the ternary system.This may be due to the fact that the relaxation of the phase covers the relaxation of the filler network.We proposed a way to determine the existence of the filler network in the ternary composites.First,determine whether the filler particles form a network in the filler-rich phase by a frequency sweep on this component.Second,use the power-law relationship to determine whether the filler-rich phase forms a network in the ternary composites.关键词：Composite;Filler network;Conductive;Dynamic rheology;Relaxation
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发布时间：2021-03-19 - 摘要：The nonlinear viscoelasticity of a thixotropic yield stress fluid (3.0 wt% Laponite hydrogel) and a non-thixotropic one (0.25 wt% Carbopol hydrogel) under large amplitude oscillatory shear (LAOS) was investigated by Fourier-transform rheology (FTR).The relative intensities of the 3rd harmonic (I3/I1) and the relative phase angle of the 3rd harmonic (3) of these two hydrogels under different stress amplitudes were compared.It is found that both the nonlinear viscoelasticity and the solid-liquid transition behavior of these two hydrogels differ greatly because of their different microscopic structures.For the Carbopol hydrogel,the nonlinear intensities change gradually with the increase of applied stress,and the transition behavior shows the correlations between the deformation,relaxation as well as relative slip of the microgel particles and the oscillatory frequency.While for the Laponite hydrogel,the nonlinear viscoelasticity exhibits a non-monotonic change,which indicates several times of shear rupture of local house-of-card structure before the full solid-liquid transition.关键词：Large amplitude oscillatory shear;Fourier-transform rheology;Nonlinear viscoelasticity;Viscoplasticity
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发布时间：2021-03-19 - 摘要：Influence of processing conditions on frequency ()-dependent dynamic rheology of vapor grown carbon nanofiber (VGCF) filled polystyrene (PS) melt (200℃) with different VGCF volume fractions (=0~0.05) was studied in the framework of a modified two phase model.In comparison with the composites processed in a strong-shear mixing condition (190℃; 120 r/min-10 min),VGCF formed aggregates to a higher degree in those processed in a weak-shear mixing condition (190℃; 30 r/min-5 min).The filler aggregation was characterized by a higher value of strain amplification factor Af() and a smaller relaxation exponent n related to the filler phase.Furthermore,strain ()-dependent amplification factor,Af(, ),and characteristic elastic and viscous moduli, Gf' (,c) and Gf (,c),were introduced to the two phase model for discussing the nonlinear rheology with increasing .The results showed that the two phase model allowed discussing dynamic rheology of filled melts qualitatively.The processing condition influenced the dispersion of VGCF in the matrix while it did not influence relationships of elastic contribution Rf' () against n for -dependent rheology as well as elastic modulus Gf' (,c) against nonlinear strain exponent x and viscous modulus Gf (,c) against nonlinear strain exponent y,suggesting that the viscoelastic contribution of the filler phase was closely related to its relaxation and structural stability.关键词：Vapor grown carbon nanofiber;Polystyrene;Dynamic rheology
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发布时间：2021-03-19 - 摘要：Continuous bundles of aligned electrospun polyacrylonitrile (PAN) precursor nanofibers of different stages in electrospinning process were prepared with a flowing water bath collector.Then the as-electrospun nanofiber bundles were stretched in hot water at 97℃ into 2 and 3 times of the original lengths.Subsequently,characterizations and evaluations were carried out to understand their morphology,diameter,density,crystalline structure and orientation using SEM,WAXD etc.The study revealed that:(1) the polymer solution jet was stretched/elongated during electrospinning process,which formed and improved the crystalline structure and orientation; during the electrospinning process,the diameter of as-electrospun nanofiber bundles was decreased from 664 nm to 353 nm,while the crystallinity and the orientation increased from 42.55% to 47.76% and 37.48% to 43.93%,respectively,which led to the density increased from 1.1917 g/cm3 to 1.1943 g/cm3; and (2) the improvement of the crystalline structure and orientation was limited when most solvent was removed during the electrospinning process,and post-spinning stretching could substantially improve the crystalline structure and orientation.Meanwhile,the improvement of the crystalline structure and orientation of as-electrospun nanofiber bundles could enhance the post-spinning stretching process.关键词：Electrospinning;Polyacrylonitrile;Crystalline structure and orientation
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发布时间：2021-03-19 - 摘要：A series of well-defined hydrophobic copolymers latexes of fluorinated acrylate (FA) with 2-methacrylatoethyl trimethyl ammonium chloride (DMC) were synthesized as potential colloidal templates,and then the core-shell FA copolymer SiO2 hybrid nanoparticles (NPs) with a mobile core were synthesized via deposition of tetramethyl orthosilicate (TMOS) in aqueous media at room temperature,allowing the formation of hollow-structured silica NPs by subsequent calcinations.No experimental evidence was found for nontemplated silica formation,which indicated that silica deposition occurred exclusively in the latex surface and formed FA copolymer-SiO2 hybrid NPs,which was confirmed by the combination of FTIR,EDX,TGA and XPS determination.Studies from TEM and TGA indicated that the morphology and composition of the resulted SiO2 hybrid nanoparticles could be well controlled by adjusting the DMC concentration,the amount of TMOS and the deposition time.Higher DMC concentration,higher level of TMOS amount or longer deposition time produced the FA copolymer-SiO2 hybrid nanoparticles with more enriched SiO2 content and thicker SiO2 shell.Moreover,the morphology of the core-shell hybrid nanoparticles with dented wrinkled surface turned to regular spherical nanoparticles with a mobile core after SiO2 deposition.These new core-shell FA copolymer-SiO2 hybrid nanoparticles with a mobile core and corresponding hollow-structured silica nanoparticles would have potential applications for high-performance encapsulation and delivery of drugs,pigments and the active organic molecules.关键词：Biomimetic synthesis;FA copolymer-SiO2 hybrid nanoparticles (NPs);Core-shell morphology;Mobile core
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发布时间：2021-03-19 - 摘要：Electrospinning was applied to prepare PEI fibrous membranes.The micro-structure of PEI fibrous membranes was studied by scanning electron microscope (SEM) and polarization infrared spectrum.The experimental results show that under the same solution concentration of PEI,the viscosity of spinning solution in the low boiling point organic solvent is higher than the viscosity in the N-methyl pyrrole (NMP),the volatility of the solvent and the viscosity of spinning solution have a great effect on the spinnability of PEI.When NMP was used as a solvent,air humidity greatly influenced the process of electrospinning and the morphology of PEI fiber.Under the same electrospinning condition,with raising the concentration of spinning solution,the parallelism of the oriented PEI fibers shows an increasing trend,and the average diameter of PEI fibers is also increasing,ranging from 400 nm to 3.5 m.The dielectric properties of PEI fibrous membranes were tested by a precision impedance analyzer (4294A,Agilent) in the frequency range of 103 Hz to 107 Hz at the room temperature and under ambient atmosphere.The results indicate that the dielectric constants of PEI oriented fibers are very low,can get to 1.1,meanwhile their dielectric loss are basically unchanged,maintaining at a very low level.The receiving methods of fibers and hot-stretching can influence the dielectric properties of PEI fibrous membranes.关键词：Electrospinning;Polyetherimide (PEI);Dielectric property;Micro-structure
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发布时间：2021-03-19 - 摘要：4-Chlorobutylferrocene was synthesized from 4-ferrocenylbutanoic acid by typical reactions of NaBH4-I2-THF reduction and thionyl chloride chlorination,in stead of the traditional method with ferrocene and 4-chlorobutyryl chlorid as raw materials,in which NaBH4-I2-THF system replaces toxic zinc amalgam as reducing agent.(4-Ferrocene-butyl) dimethyl silane was perpared from dimethyl chlorosilane and format reagent which was produced by magnesium powder and 4-chlorobutyl ferrocene.The butacene with high yield,which was formed from hydrosilylation,was successfully obtained by reaction of (4-ferrocene-butyl) dimethyl silane and hydroxyl-terminated polybutadiene(HTPB) in the presence of the efficient and reusable platinum catalyst (silica-supported chitosan complex of chloroplatinic acid SiO2-CS-Pt).The structure of the polymer was characterized by 1H-NMR and FTIR.Thermal stability of the polymer was studied using TGA.This work also measured the rate of grafting and the hydroxyl value.The results show that the desired target product with the advanced initial decomposition temperature,increased thermal sensitivity,increased thermal stability and excellent catalytic performance was obtained.关键词：Butacene;NaBH4-I2-THF;HTPB;Latinum catalyst
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发布时间：2021-03-19 - 摘要：Poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) hollow fiber membranes were prepared by melt spinning method with FEP as polymer matrix,composite of inorganic particles as pore-forming agent and dioctyl phthalate (DOP) as the diluent.The pure water flux and pore size distribution of the hollow fiber membranes were tested.Effect of FEP and composite of inorganic particles contents on the thermal properties,changes in thermodynamic properties and mechanical properties of the hollow fiber membranes were analyzed and discussed.The cross-section and surface morphologies of the hollow fiber membranes were observed by scanning electronic microscopy (SEM).The results showed that the spongy-like structure could be observed obviously in the cross-section of the hollow fiber membrane,which consisted of dissolved micro-voids and interfacial micro-voids formed by stretching.As the pore-forming agent contents increasing,the dispersed homogeneous degree became worse,which would brought about not only larger pores but also wider pore size distribution.The impact of pore-forming and diluent on the thermal properties and thermodynamic properties of the hollow fiber membranes was little.As the FEP contents reached 70 wt%,the compact layers formed on the hollow fiber surface induced the decrease of FEP hollow fiber membrane permeability.关键词：FEP;Melt-spinning;Hollow fiber membrane;Property
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发布时间：2021-03-19 - 摘要：Ferrocene-grafted polyethyleneimine (PEI-Fc) was synthesized via the reaction of ferrocene carboxaldehyde with branched PEI.The graft level of Fc was about 8.35%.Based on the host-guest interaction between ferrocene and -cyclodextrin (CD),CD-modified PEI was successfully prepared.1H-NMR spectrum indicated that there were 26 CD molecules per PEI-Fc chain.CD-modified PEI via host-guest interaction showed effective DNA condensation ability.At N/P ratio above 3,the positive nanoparticles with diameter of about 150~250 nm were formed.At the cell culture medium of DMEM with 10% FBS,PEI-Fc/CD/DNA polyplexes showed excellent stability.It was probably due to the electronic adsorption of proteins on the surface of polyplexes.HEK293 cells culture results indicated that the transfection of PEI-Fc/CD/DNA polyplexes at N/P ratio of 3,5 and 10 was almost 2~3 folds of that of PEI polyplexes at N/P ratio of 10.The CD modified PEI via host-guest interactions significantly improved the transfection efficiency.关键词：Non-viral gene vectors;Host-guest assembly;PEI;Cyclodextran
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发布时间：2021-03-19 - 摘要：The present study examined the effect of mesophase separation on the crystallizaiton behavior of olefin block copolymer (OBC).Two OBCs with different C8 (octene content difference between the soft and hard segments) were chosen,which were shown to have different phase and crystallization morphology in the solid state.The melt morphology was further examined by rheology.The isothermal crystallization dynamics of OBCs was investigated by differential scanning calorimetry (DSC).The morphology of OBCs after isothermal crystallization was observed utilizing an atomic force microscope (AFM).The results showed that the both the two OBCs exhibited mesophase separation well above the melting temperature.Upon isothermal crystallization,the OBC with higher C8 kept the mesophase separated morphology,while the OBC with lower C8 displayed random distributed lamellar structure.Both the two OBCs had Avrami parameter n 3,indicating that crystallization of OBC with mesophase separation exhibited a three dimensional spread manner.This striking phenomenon was attributed to the phase mixing in OBCs.Some shorter crystalline hard segments can dissolve in the amorphous soft phase,which can transfer the growth of crystals into adjacent hard segment domains upon crystallization.关键词：Olefin Block Copolymer;Phase separation;Crystallization
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发布时间：2021-03-19 - 摘要：The PP/POE blends with different contents of compatibilizer were prepared by melt mixing process,and the brittle-ductile transition behavior,thermal property and mechanical performance of the PP/POE blends were examined.The results showed that the addition of ethylene-propylene block copolymer based compatibilizer decreased the brittle-ductile transition temperature of PP/ POE blends accordingly.AFM results suggested that proper contents of compatibilizer induced the well dispersion and phase morphologies of POE particles in PP matrix.STEM results showed that the compatibilizer decreased the critical interparticle distance (IDc) of POE domains,leading to their homogeneous distribution.The dispersed POE particles and PP matrix diffused and interpenetrated into each other near the edge of their interfaces,indicating the improvement of the blend systems compatibility.When the content of compatibilizer reached 10%,the small and well homogenous POE domains were obtained and the obvious hard core - tough shell structures of POE domains were formed.The average diameter of POE domains was 0.54 m and the interparticle distance was 0.1 m.The DSC curves during the cooling and the second heating runs demonstrated that the incorporation of proper content of compatibilizer could enhance the crystallization degree of PP/POE blends.Mechanical testing data illustrated that the addition of compatibilizer not only enhanced the toughness of PP/POE blends and decreased their brittle-ductile transition temperature,but also maintained the materials stiffness,so the stiffness-toughess balance of the PP/POE blends was well kept.关键词：Polypropylene;Poly(ethylene-co-1-octene);Compatibilizer;Brittle-ductile transition;Impact strength;Stiffness-toughess balance
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发布时间：2021-03-19 - 摘要：A kind of active ether compound with acetal structure was synthesized through the adding-reaction between ethyl vinyl ether and pyrogallol polycondensation resins.The optimized reaction conditions are as follows:35℃,the mixture of methylene chloride and acetone (50∶50) as the solvent,sulfamic acid as the catalyst,the molar ratio of vinyl ether to phenolic hydroxyl group being 3∶1,reacting for 14 h.This kind of active ether compound can be used in room temperature chemically amplified positive photosensitive imaging and positive thermal imaging as an inhibitational/accelerational reagent for being able to be acid-decomposed and heat-decomposed under room temperature.Being used in CTP thermal imaging directions,it makes for the plates high sensitivity,anti-alkaline and high stability.Being used in positive CTcP photosensitive imaging directions,it makes for the plates excellent performance of integrated imaging.Being used in positive photoresist imaging directions,it makes for the positive photoresist high sensitivity and high resolution.关键词：Active ether compounds;Inhibitational/accelerational reagents;Positive thermal CTP plates;Positive CTcP plates;Positive photoresist
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发布时间：2021-03-19 - 摘要：Using the obtained porous honeycomb-structured films via breath figures method as molding substrates,we prepared poly(dimethylsiloxane) (PDMS) negative replica (reverse honeycomb-structured substrate) with arrays of island-like protuberances by means of soft lithography.Utilizing the patterned micro-sized PDMS arrays as substrate,hierarchical superhydrophobic surfaces were successfully fabricated by introducing nano-scale roughness via two different methods.For the first method,chemical deposition of silver nanoparticles onto PDMS substrate was achieved by applying silver mirror reaction.Compact layers of silver nanoparticles were formed wrapping the PDMS protuberances nicely.Contact angle as high as 166? was achieved.Layer-by-layer (LBL) assembly of polyelectrolyte/silica nanoparticles was employed for the second method.After two cycles of assembly,the deposited silica nanoparticles together with micro-sized PDMS protuberances form an ideal composite structure which endows the obtained surface with superhydrophobic property.Simple ways were shown to demonstrate the potential of the breath figures method to construct functional structure.It is a solid way to fabricate micro-sized patterned template via breath figures method.With further second-processing steps,certain novel properties can be endowed depending on the ordered structures.关键词：Breath figure method;Honeycomb structure;Superhydrophobic surface;Micro- and nanoscale hierarchical structure
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发布时间：2021-03-19 - 摘要：In this study,first,the preparation process of poly(R-3-hydroxybutyrate-co-R-3-hydroxyhexanoate) (PHBHHx) (with 12 mol% HHx content) original fiber was optimized by lowering down the extrusion temperature to 120℃,which could greatly accelerate the crystallization rate and shorten the subsequent processing time.Then,PHBHHx fibers with excellent mechanical properties were successfully obtained following an isothermal crystallization-drawing-annealing with fixed ends processing technique.The average tensile strength could reach up to 262 MPa,with an elongation at break of still larger than 120%.Two-dimensional X-ray diffraction measurements and Raman spectroscopy showed that the polymer chains in the high-strength PHBHHx fibers were highly oriented along the drawing direction both in crystalline and amorphous regions,and no crystal modification was observed in the highly oriented PHBHHx fibers with or without annealing procedure,which was quite different from poly(R-3-hydroxybutyrate) (PHB) fiber and poly(R-3-hydroxybutyrate-co-R-3-hydroxyvalerate) (PHBV) fiber.Dynamic mechanical analysis (DMA) results demonstrated that annealing procedure was beneficial for improving the storage module (G') of fibers.For example,after annealing at 70℃ for 3 h,the G' could be doubled at 30℃ and increased by five folds at 40℃.Further study revealed that the mechanical properties of fibers could be easily regulated by changing the annealing conditions,which would guide the further study and lead to wide potential applications of PHBHHx materials.关键词：Poly(R-3-hydroxybutyrate-co-R-3-hydroxyhexanoate);Fiber;Processing technique;Mechanical properties
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发布时间：2021-03-19 - 摘要：Micron-sized silica gel particles were surface-modified with coupling agent -aminopropyltrimethoxysilane (AMPS),obtaining the modified particles AMPS-SiO2.A redox initiating system was constituted by the amino groups on the surface of AMPS-SiO2 particles and persulfate in the solution,and the surface-initiated graft-polymerization of 2-hydroethyl methacrylate was performed,resulting in the grafted particles PHEMA/SiO2.Subsequently,a polymer reaction of the grafted PHEMA was carried out,and it was the nucleophilic substitution reaction between the hydroxyl group of the grafted PHEMA and the chloromethyl group of 5-chloromethyl-8-hydroxyquinoline (CHQ).As a result,the 8-hydroxyquinoline-functionalization transform of the grafted PHEMA was realized,obtaining the functional composite particles HQ-PHEMA/SiO2.The two kinds of particles were characterized by several methods.In this work,the graft-polymerization mechanism for the amino group-persulfate initiation system was mainly investigated,and the mechanism of the substitution reaction between the hydroxyl group of the grafted PHEMA and the chloromethyl group of CHQ was also explored in depth.Finally,the chelating adsorption property of HQ-PHEMA/SiO2 for heavy metal ions was preliminarily examined.The experimental results show that the amino group-persulfate initiation system has very high initiation activity,and it can effectively initiates the graft-polymerization of HEMA on silica gel particles.At room temperature (30℃),the grafted particles PHEMA/SiO2 with high grafting degree (40 g/100 g) can obtained.The substitution reaction between the hydroxyl groups of the grafted PHEMA and CHQ has a reaction mechanism of SN1,and using the solvent with strong polarity is advantageous to the reaction.The functional particles HQ-PHEMA/SiO2 possess very strong chelating adsorption ability for heavy metal ions.The functional composite particles are promising and potential in the analysis and separation fields.关键词：2-Hydroethyl methacrylate;8-Hydroxyquinoline;Surface-initiated graft-polymerization;Nucleophilic substitution reaction;Chelation adsorption
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发布时间：2021-03-19 - 摘要：A conjugated polymer ( P0 ) containing tetraphenylethene (TPE) group and benzothiadiazole (BT) group has been designed and synthesized by Suzuki coupling reaction of 1,2-di［4-(6-bromohexyloxy)phenyl］-1,2-di(4-bromophenyl)ethene ( M1 ),1,2-di［4-(6-bromohexyloxy) phenyl］-1,2-di(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)ethylene ( M2 ) and 4,7-dibromo-2,1,3-benzothiadiazole ( M3 ).The ratio of TPE unit to BT unit at 0.803∶0.197 was determined by 1H-NMR spectrum.A water-soluble cationic conjugated polyelectrolyte ( P1 ) is obtained by quaternization P0 with trimethylamine,which is completely soluble in water and insoluble in common organic solvents such as THF and acetone.When P1 is aggregated by adding a poor solvent such as THF into P1 aqueous solution,the fluorescence intensity and color of P1 change drastically.The intensity increases up to seven times and the maximum emission peak is red-shifted up to 30 nm.The color is changing from khaki (no aggregation)to orange (aggregation)under ultraviolet irradiation.Therefore,dual-channel fluorescence response as the unique properties of P1 was applied to detect heparin,a highly sulfated glycosaminoglycan with the highest negative charge density among the known biological molecules.The fluorescence intensity gradually increased upon addition of heparin into P1 aqueous solution with a linear response to concentration of heparin,and the correlation coefficient was up to 0.9999.In addition,a linear red shift of the maximum emission peak was observed as the concentration of heparin increased with a correlation coefficient up to 0.9998.These results indicate that P1 is a potential material for developing dual-channel fluorescence probe for heparin quantification.The UV spectra of P1 /heparin complexing titration dont show any change.This indicates that there is no inter-chains or intra-chains - stacking of P1 .DLS result indicates some aggregates can be formed through electrostatic interaction between P1 and heparin,which can reduce the radiative decay when the intramolecular rotation of phenyl group on the side chains is restricted and the fluorescent emission can correspondingly be enhanced.Moreover,due to existence of BT,a typical fluorescence acceptor in fluorescence resonance energy transfer,the fluorescence of TPE segments can effectively be transferred to BT segments when the aggregates are formed by electrostatic interaction between P1 and heparin,which leads to red-shifts of the maximum emission wavelength.Based on these different responses to electrostatic interaction between P1 and heparin,dual-channel signals can be obtained as the above discussion.This study thus provides a new concept for designing dual-channel fluorescence sensing material.关键词：Tetraphenylethene (TPE);2,1,3-Benzothiadiazole;Heparin;Conjugated polyelectrolyte;Fluorescence resonance energy transfer (FRET)
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发布时间：2021-03-19 - 摘要：Trimethylated chitosan-O-poly(-caprolactone) (TMC-PCL) micelles were used as nanocarriers for co-loading of two types of drugs with distinct hydrophilicity,including FDA-approved near-infrared (NIR) photosensitizer,indocyanine green (ICG) and a first-line anti-cancer drug,doxorubicin (DOX).Both two agents could be incorporated within the micelles with entrapment efficiency of more than 85% and loading content of up to 20%.The loading content could be adjusted by varying feed ratio of the agents to the micelles.A red-shift in absorption peak of ICG from 780 nm to 800 nm was observed upon incorporation in to the micelles.The competitive binding of the micelles to ICG molecules also increased the momoner/dimer ratio of ICG.TMC-PCL micelles showed an excellent ICG retention ability,and only 18.18% of ICG was leaked from micelles after 48 hours incubation in physiological media.In addition,the incorporation of ICG within the micelles enhanced its thermal and optical stability.ICG-loaded micelles (ICG-micelles) exhibited higher heating capacity than free ICG.DOX release behavior was affected by the temperature,while the presence of ICG within the micelles had little effect on DOX release.The cytotoxicity of the dual-agent-loaded micelles towards HepG2 cells was found to be higher than that of single-agent-loaded counterparts.关键词：Chitosan;Cationic micelle;Co-incorporation;Tumor targeting
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发布时间：2021-03-19 - 摘要：Crosslinked maleic anhydride-vinyl acetate copolymer microspheres were synthesized by charge transfer complexes (CTC) self-stable precipitation polymerization with mean diameter of about 150 nm.Afterwards,copolymer microspheres/poly(ethylene) composites (CM/LLDPE) with low CM contents were used as pre-dispersed composites and melt-mixed with nylon6 (PA6) resin to prepare a series of PA6/LLDPE/CM composites with low CM contents.It was found that the divinylbenzenes double bond groups and poly(ethylene),anhydride groups and nylon6 produced chemical reaction on phase interface respectively.According to the SEM analyses,it was found that the effect of various amounts of copolymer microspheres on the morphological structure and size of dispersed phase was obvious.It can effectively reduce the size of dispersed phase to fill the copolymer microspheres; on the surface of poly(ethylene) dispersed phase,the nano-sized microspheres played the role of a dispersed phase stabilizer,and this was similar to the emulsifier in emulsion polymerizationin.When the nano-sized microspheres content reached about 1.75%,the performance of composites was improved obviously:the impact strength of composites was increased by 1.35 times compared to pure nylon 6,although the tensile strength and Youngs modulus of composites were reduced by about 10%.The water absorption percentage droped to 1.2% compared to 4.9% of pure nylon 6.The toughening mechanism was also discussed in this paper;it was a new and important method to compatibilize two phase by stabilizing the size of dispersed phase.关键词：Maleic anhydride-vinyl acetate copolymer microspheres;Nylon 6;Linear low density poly-(ethylene);Compatibility;Dispersed phase stabilizer
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发布时间：2021-03-19
Research Article
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