A new principle for producing fire-resistant polymer materials with increased deformation properties using a flame retardant not as a heterogeneous additive,but as a thermoplastic flame retardant in a hybrid polymer m...A new principle for producing fire-resistant polymer materials with increased deformation properties using a flame retardant not as a heterogeneous additive,but as a thermoplastic flame retardant in a hybrid polymer mixture with a polyhydrocarbon is considered.Hybrid polymer blends of low-molecular ammonium polyphosphate(APP)with an ethylene-vinyl acetate copolymer(EVA)with an APP content of 80 wt%with enhanced deformation properties were obtained by extrusion mixing at various temperatures in the range from 200°C to 250°C.A chemical scheme for the transformations of the components during the formation of the composite is proposed.X-ray diffraction analysis showed the formation of new crystalline structures of APP.The phase structure of the systems corresponding to the model of a dispersed-filled composite in which EVA plays the role of a matrix,determining the deformation of the mixture,and the filler is ammonium polyphosphate,was studied by scanning electron microscopy(SEM).The method of FTIR microscopy showed chemical interactions between EVA and APP with the formation of amide groups.The conditions for obtaining compositions characterized by heat resistance of 210°C,oxygen index of 55 and ultimate elongation at drawing of 213%were established.展开更多
The equilibrium dynamics and nonlinear rheology of unentangled polymer blends remain inadequately understood,especially regarding the influence of short-chain matrix length N_(S) on the structure and rheological behav...The equilibrium dynamics and nonlinear rheology of unentangled polymer blends remain inadequately understood,especially regarding the influence of short-chain matrix length N_(S) on the structure and rheological behavior of dispersed long chains.Using molecular dynamics simulations based on the Kremer-Grest model,we systematically explore the N_(S)-dependence of static conformations,equilibrium dynamics,and nonlinear shear responses in unentangled long-chain/short-chain polymer blends.Our results demonstrate a decoupling between the static and dynamic sensitivity to N_(S):while the static chain size,R_g,follows Flory theory with slight swelling at small N_(S) due to incomplete excluded volume screening,the diffusion coefficient,D,and the relaxation time,τ_(0),exhibit a strong,non-monotonic N_(S)-dependence,transitioning from monomeric friction dominance at small N_(S) to collective segmental rearrangement at large N_(S).Additionally,we observe partial decoupling between the viscous and normal stress responses:while the zero-shear viscosity,η,is strongly N_(S)-dependent,the first and second normal stress coefficients,Ψ_(1) and Ψ_(2),collapse onto universal curves when scaled by the dimensionless shear rate,γτ_(0),suggesting a common mechanism of orientation and stretching.Under shear,long chains compress in the vorticity direction λ_(z)~Wi^(-0.2),which reduces collision frequency and contributes to shear thinning,while the scaling of weaker orientation resistance m_(G)~Wi^(0.35)reflects hydrodynamic screening by the short-chain matrix.These findings highlight the limitations of single-chain models and emphasize the necessity of considering N_(S)-dependent matrix dynamics and flow-induced structural changes in understanding the rheology of unentangled polymer blends.展开更多
High-entropy polymer blends composed of polypropylene(PP),polystyrene(PS),polyamide 6(PA6),poly(lactic acid)(PLA),and styrene-ethylene-butylene-styrene(SEBS)were successfully fabricated using maleic anhydride-grafted ...High-entropy polymer blends composed of polypropylene(PP),polystyrene(PS),polyamide 6(PA6),poly(lactic acid)(PLA),and styrene-ethylene-butylene-styrene(SEBS)were successfully fabricated using maleic anhydride-grafted SEBS(SEBS-g-MAH)as a compatibilizer.Dynamic mechanical analysis(DMA),differential scanning calorimetry(DSC),scanning electron microscopy(SEM),and mechanical testing demonstrated that SEBS-g-MAH significantly enhanced the compatibility between the polar(PA6,PLA)and nonpolar(PP,PS,SEBS)components.The compatibilizer effectively refined the microstructure,substantially reduced the domain sizes,and blurred the phase boundaries,indicating enhanced interfacial interactions among all the components.The optimal compatibilizer content(15 wt%)notably increased tensile ductility(elongation at break from 5.0%to 23.7%)while maintaining balanced crystallization behavior,despite slightly decreasing modulus.This work not only demonstrates the broad applicability of high-entropy polymer blends as a sustainable strategy for converting complex,unsorted plastic waste into high-performance value-added materials that significantly contribute to plastic upcycling efforts,but also highlights intriguing physical phenomena emerging from such complex polymer systems.展开更多
Immiscible polymer blends are an important family of polymer materials.The interfacial thickness between different phases is a very important parameter that dictates,to a great extent,the morphology and properties of ...Immiscible polymer blends are an important family of polymer materials.The interfacial thickness between different phases is a very important parameter that dictates,to a great extent,the morphology and properties of such a blend.This work explores and optimizes an up-to-date atomic force microscopy(AFM)of type NanoIR2^(TM) system in order to quantitatively measure the interfacial thickness of immiscible polymer blends.This system is equipped with two nano-probes capable of detecting the response of a material to an infrared pulse called AFM-infrared spectroscopy mode(AFM-IR)or conducting resonance called AFM-Lorentz Contact Resonance mode(AFM-LCR),respectively.Its potential for quantitatively measuring the interfacial thickness of immiscible polymer blends is evaluated using blends composed of polyamide 6(PA6)and polyolefin elastomer(POE)in the presence or absence of a POE containing maleic anhydride(POE-g-MAH)as a compatibilizer.Surface roughness affects adversely the signal intensity and consequently an accurate measurement of the interfacial thickness.Optimum sample surface preparation procedures are proposed.展开更多
The effects of blend composition and micro-phase structure on the mechanical behavior of A/B polymer blend film are studied by coupling the Monte Carlo(MC) simulation of morphology with the lattice spring model(LSM) o...The effects of blend composition and micro-phase structure on the mechanical behavior of A/B polymer blend film are studied by coupling the Monte Carlo(MC) simulation of morphology with the lattice spring model(LSM) of micro mechanics of materials.The MC method with bond length fluctuation and cavity diffusion algorithm on cubic lattice is adopted to simulate the micro-phase structure of A/B polymer blend.The information of morphology and structure is then inputted to the LSM composed of a three-dimensional network of springs to obtain the mechanical properties of polymer blend film.Simulated results show that the mechanical response is mainly affected by the density and the composition of polymer blend film through the morphology transition.When a force is applied on the outer boundary of polymer blend film,the vicinity of the inner cavities experiences higher stresses and strains responsible for the onset of crack propagation and the premature failure of the entire system.展开更多
Poly（vinylidene fluoride） （PVDF） and poly（butylene succinate-co-24 mol% hexamethylene succinate） （PBHS）, both crystalline polymers, formed melt-miscible crystalline/crystalline polymer blends. Both the charact...Poly（vinylidene fluoride） （PVDF） and poly（butylene succinate-co-24 mol% hexamethylene succinate） （PBHS）, both crystalline polymers, formed melt-miscible crystalline/crystalline polymer blends. Both the characteristic diffraction peaks and nonisothermal melt crystallization peak of each component were found in the blends, indicating that PVDF and PBHS crystallized separately. The crystalline morphology and crystallization kinetics of each component were studied under different crystallization conditions for the PVDF/PBHS blends. Both the spherulitic growth rates and overall isothermal melt crystallization rates of blended PVDF decreased with increasing the PBHS composition and were lower than those of neat PVDF, when the crystallization temperature was above the melting point of PBHS component. The crystallization mechanism of neat and blended PVDF remained unchanged, despite changes of blend composition and crystallization temperature. The crystallization kinetics and crystalline morphology of neat and blended PBHS were further studied, when the crystallization temperature was below the melting point of PBHS component. Relative to neat PBHS, the overall crystallization rates of the blended PBHS first increased and then decreased with increasing the PVDF content in the blends, indicating that the preexisting PVDF crystals may show different effects on the nucleation and crystal growth of PBHS component in the crystalline/crystalline polymer blends.展开更多
Various viscosity-composition curves of polymer blends are summarized in eight groups. To represent these curves. 'sub-cluster equations' are derived on the basis of so called 'sub-cluster theoryThe essent...Various viscosity-composition curves of polymer blends are summarized in eight groups. To represent these curves. 'sub-cluster equations' are derived on the basis of so called 'sub-cluster theoryThe essential concepts of sub-cluster theory and the derivation of those 'Sub-cluster equations' are briefly introduced.展开更多
Mixing two or more polymers to produce the“polymer alloy”is one of the most versatile and economical strategies for developing new polymeric materials.The compatibility between polymer components largely determines ...Mixing two or more polymers to produce the“polymer alloy”is one of the most versatile and economical strategies for developing new polymeric materials.The compatibility between polymer components largely determines the comprehensive performance of polymer blend.More recently,a type of unique surface partitioned materials,Janus particles,has been proposed to act as a novel interfacial compatibilizer for polymer blends.Such Janus particles integrates the amphipathicity of diblock copolymer and interfacial stabilization of nanoparticles,displaying a significant superiority in comparison with molecular compatibilizers for a wide range of polymer blends.In this review,we mainly focus on the compatibilizing effects of Janus nanofillers of various morphologies,including spherical,snowman-like,and two-dimensional nanosheets,on polymer blends.We shed light on the impacts of compatibilization of Janus particles on phase morphologies,mechanical properties,and functionalities of polymer blends.This review could provide a guidance for designing an effective Janus particle compatibilizer to develop high-performance polymer blends.展开更多
The effect of silica nanoparticles on the morphology of （10/90 wt%） PDMS/PBD blends during the shear induced coalescence of droplets of the minor phase at low shear rate was investigated systematically in situ by us...The effect of silica nanoparticles on the morphology of （10/90 wt%） PDMS/PBD blends during the shear induced coalescence of droplets of the minor phase at low shear rate was investigated systematically in situ by using an optical shear technique. Two blending procedures were used： silica nanoparticles were introduced to the blends by pre-blending silica particles first in PDMS dispersed phase （procedure 1） or in PBD matrix phase （procedure 2）. Bimodal or unimodal droplet size distributions were observed for the filled blends during coalescence, which depend not so much on the surface characteristics of silica but mainly on blending procedure. For pure （10/90 wt%） PDMS/PBD blend, the droplet size distribution exhibits bimodality during the early coalescence. When silica nanoparticles （hydrophobic and hydrophilic） were added to the blends with procedure l, bimodal droplet size distributions disappear and unimodal droplet size distributions can be maintained during coalescence; the shape of the different peaks is invariably Gaussian. Simultaneously, coalescence of the PDMS droplets was suppressed efficiently by the silica nanoparticles. It was proposed that with this blending procedure the nanoparticles should be mainly kinetically trapped at the interface or in the PDMS dispersed phase, which provides an efficient steric barrier against coalescence of the PDMS dispersed phase. However, bimodal droplet size distributions in the early stage of coalescence still occur when incorporating silica nanoparticles into the blends with procedure 2, and then coalescence of the PDMS droplets cannot be suppressed efficiently by the silica nanoparticles. It was proposed that with this blending protocol the nanoparticles should be mainly located in the PBD matrix phase, which leads to an inefficient steric barrier against coalescence of the PDMS dispersed phase; thus the morphology evolution in these filled blends is similar to that in pure blend and bimodal droplet size distributions can be observed during the early coalescence. These results imply that exploiting non-equilibrium processes by varying preparation protocol may provide an elegant route to regulate the temporal morphology of the filled blends during coalescence.展开更多
Low cycle fatigue crack propagation (FCP) behavior of two PC/ABSblends with a weight ra- tio of PC to ABS being 80/20 and 60/40,respectively, is investigated. Experiments are carried out by usingstandard compact tensi...Low cycle fatigue crack propagation (FCP) behavior of two PC/ABSblends with a weight ra- tio of PC to ABS being 80/20 and 60/40,respectively, is investigated. Experiments are carried out by usingstandard compact tension (CT) specimens. The fracture surfaces areexamined with a scanning electron mi- croscope (SEM). It is shownthat the FCP resistance of PC/ABS blend with 20/100 ABS particles ishigher than that of PC/ABS blend with 40/100 ABS particles. It isfound that proper ABS particle content can result in the tougheningof PC/ABS blends through particle cavitation and shear yielding inmatrix.展开更多
A fast coalescence mechanism is proposed to account for the wall effect on the formation of gradient morphology in phase separated polymer blends during quiescent annealing. The existence of solid wall with high polar...A fast coalescence mechanism is proposed to account for the wall effect on the formation of gradient morphology in phase separated polymer blends during quiescent annealing. The existence of solid wall with high polarity is believed to change the potential field around the dispersed particles near the wall. This additional potential interaction between the solid wall and the dispersed particles causes faster coalescence of the dispersed particles near the wall than in the bulk. The gradient phase morphology thus formed can be predicted by combining the wall-particle interaction and the touch-coalescence mechanism. The effect of interfacial tension on the gradient morphology is also discussed.展开更多
Silica rods with homogeneous(hydrophilic or hydrophobic)and amphiphilic surface properties were synthesized and their efficiencies in suppressing the flow-induced droplet coalescence of immiscible polyisobutylene(PIB)...Silica rods with homogeneous(hydrophilic or hydrophobic)and amphiphilic surface properties were synthesized and their efficiencies in suppressing the flow-induced droplet coalescence of immiscible polyisobutylene(PIB)/polydimethylsiloxane(PDMS)blends were evaluated via in situ visualization technique.The flow-induced coalescence behavior of blends was found to strongly depend on the surface nature and concentration of silica rods added as well as the blend ratio.While a trace amount of rods promoted coalescence,all kinds of rods demonstrated a morphology refinement effect at high rod concentrations.Good compatibilization effects were obtained at high rod concentrations,especially for hydrophilic and amphiphilic rods.Based on confocal laser scanning microscopy results,these phenomena observed were interpreted reasonably in terms of the selective distribution and aggregation of silica rods,which were suggested to be decisive for the stabilization mechanism and efficiency of these rods.展开更多
Series of PVC/ABS and PVC/SBS blends of composition 20/ 80. 40/ 60, 60 / 40 and 80 / 20were prepared in a screw extruder. The phase morphology, miscibility and rheological behaviour of two systems were investigated. T...Series of PVC/ABS and PVC/SBS blends of composition 20/ 80. 40/ 60, 60 / 40 and 80 / 20were prepared in a screw extruder. The phase morphology, miscibility and rheological behaviour of two systems were investigated. The viscosity-composition plots were represented by sub-cluster equation, the various differences between two systems are interpreted with the equation parameters展开更多
Compatibility of poly (vinyl acetate) (PVAc) with poly (methyl methacrylate) (PMMA) mixtures has been studied by using nuclear magnetic relaxation, differential scanning calorimeter and small-angle X-ray scattering te...Compatibility of poly (vinyl acetate) (PVAc) with poly (methyl methacrylate) (PMMA) mixtures has been studied by using nuclear magnetic relaxation, differential scanning calorimeter and small-angle X-ray scattering techniques. The nuclear magnetic relaxation time T_1's were measured as a function of composition in blends of PMMA and PVAc prepared from chloroform solution. The results show that the system is miscible for casting from chloroform solution.展开更多
The polymer blend technique is a novel method to produced carbon nanofibers. In this paper, we have prepared fine carbon fibers and porous carbon materials by this technique, and we will discuss the experiment results...The polymer blend technique is a novel method to produced carbon nanofibers. In this paper, we have prepared fine carbon fibers and porous carbon materials by this technique, and we will discuss the experiment results by means of SEM, TGA, Element Analysis, etc.展开更多
Commercial-level sodium metal batteries require electrolytes with high ionic mobility and excellent thermo-mechanical and electrochemical stability.Conventional flammable liquid electrolytes,prone to dendrite growth a...Commercial-level sodium metal batteries require electrolytes with high ionic mobility and excellent thermo-mechanical and electrochemical stability.Conventional flammable liquid electrolytes,prone to dendrite growth and unstable interfacial reactions,rarely perform beyond coin-cell demonstrations.To address these shortcomings,a multifunctional composite quasi-solid polymer electrolyte(QSPE)that incorporates boron nitride(BN)as an engineered filler in a highly conductive polymer blend system has been developed.The optimized formation(15BN QSPE)delivers a room-temperature ionic conductivity of 2.15 m S cm^(-1)and a sodium-ion transference number of 0.80.Molecular dynamics simulations elucidate the coordination environment and show improved transport in the presence of BN.BN is chemically active and bifunctional:boron acts as an electron acceptor,interacting with solvents and macromolecules,while nitrogen coordinates with sodium ions,tailoring the solvation environment and transport pathways to promote efficient ion migration.The 15BN QSPE is self-extinguishing,resists oxidative thermal degradation,and enables stable cycling in symmetric sodium cells for>1400 h at0.5 m A cm^(-2).A Prussian blue full cell achieves>1500 stable cycles at 1C with -99% Coulombic efficiency in coin-cell configuration.A two-layer pouch cell with dual 15BN QSPE layers delivers 600 stable cycles at 0.125C and withstands rigorous mechanical abuse.These results position 15BN QSPE as a scalable,highperformance electrolyte offering enhanced safety and efficiency for next-generation sodium metal batteries.展开更多
The visualization of phase separation in immiscible polymer blends holds significant industrial and academic relevance,as the resultant phase architecture governs the macroscopic properties and ultimate performance of...The visualization of phase separation in immiscible polymer blends holds significant industrial and academic relevance,as the resultant phase architecture governs the macroscopic properties and ultimate performance of blended materials.To address this challenge,a dual-fluorophore labeling strategy is introduced,enabling high-contrast differentiation of polymeric phases.By covalently tethering two spectrally orthogonal fluorophores to their respective polymer components,unambiguous spatial resolution of blend morphologies is achieved through laser scanning confocal microscopy(LSCM).When compatibilizers are incorporated,LSCM imaging reveals fundamentally reconfigured phase architectures compared to uncompatibilized systems.This fluorescence-based approach permits direct assessment of blend compatibility through quantitative evaluation of interfacial domain coherence and phase dispersion homogeneity.The methodology demonstrates exceptional versatility,successfully resolving phase boundaries in both chemically dissimilar systems(e.g.,polylactic acid[PLA]/poly(butylene adipate-co-terephthalate)[PBAT]blends with pronounced polarity disparities)and structurally congruent polymers(e.g.,polyethylene[PE]/polypropylene[PP]variants).The universal applicability stems from the substantial spectral distinction between fluorophore-labeled polymers,independent of variations in polymer polarity or structural configurations.展开更多
Polyethylene oxide （PEO）-polyvinylpyrrolidone （PVP） blended Na＋ ion conducting solid polymeric membranes： （1-x） [75PEO：25NaPO3] ＋ x PVP, where 0 〈 x 〈 12 wt%, are reported. The polymeric blending was done ...Polyethylene oxide （PEO）-polyvinylpyrrolidone （PVP） blended Na＋ ion conducting solid polymeric membranes： （1-x） [75PEO：25NaPO3] ＋ x PVP, where 0 〈 x 〈 12 wt%, are reported. The polymeric blending was done using a solvent- free hot-press method. Two orders of conductivity enhancement （σca. 1.07× 10^-5 S·cm^-1） have been achieved with 3 wt% of PVP （i.e. the composition： [97（75PEO：25NaPO3） ＋ 3PVP]）, from that of the pure host： （75PEO：25NaPO3）. The conductivity enhancement in PEO-PVP blended solid polymeric membranes have been explained by the ionic conductivity, ionic mobility and mobile ion concentration measurements. Materials characterization and polymer-salt complexation were done with the help of X-ray diffraction （XRD）, scanning electron microscopy （SEM）, differential scanning calorimetry （DSC） and thermo gravimetric analysis （TGA） studies. The temperature dependent conductivity studies have also been done to compute the activation energy （Ea） values from lgσ-1/TArrhenius plots. A solid state polymeric battery was fabricated by using optimum conducting composition of solid polymer electrolyte （SPE OCC）, and some important cell parameters were also calculated from the discharge profile of the cell.展开更多
The diffusion and subsequent copolymerization of styrene （St）/butyl methacrylate （BMA） mixed monomers in iPP pellets to prepare copolymer nanoblends were investigated. The diffusion step was carded out at 90 ℃ fo...The diffusion and subsequent copolymerization of styrene （St）/butyl methacrylate （BMA） mixed monomers in iPP pellets to prepare copolymer nanoblends were investigated. The diffusion step was carded out at 90 ℃ for 2 h in water, and the copolymerization was initiated by the addition of BPO with the aid of a small amount of St. The diametrical distributions of both St and BMA units and their ratio St/BMA were investigated by micro FTIR. Both St and BMA can diffuse into the centres of iPP pellets. The diametrical distribution of St/BMA ratio is constant in all the copolymer blends. The copolymer composition depends on the comonomer feed ratio. The molecular weights of the copolymers were measured by GPC after extraction with tetrahydrofuran. The phase morphology of the copolymer blends was investigated by FESEM, showing the average particle sizes of less than 100 nm. DSC measurements show that the diffusion and subsequent copolymerization of St/BMA monomers only occur in the amorphous regions of iPP pellets.展开更多
A polymer blend comprising poly(3-hexylthiophene)(P3HT)donor and poly[2,7-(9,9′-octyl-fluorene)-alt-5,5-(4′,7′-di-2-thienyl-5′,6′-bis(hexyloxy)-2′,1′,3′-benzothiadiazole)](PFDTBT-OC6)acceptor is used as the ac...A polymer blend comprising poly(3-hexylthiophene)(P3HT)donor and poly[2,7-(9,9′-octyl-fluorene)-alt-5,5-(4′,7′-di-2-thienyl-5′,6′-bis(hexyloxy)-2′,1′,3′-benzothiadiazole)](PFDTBT-OC6)acceptor is used as the active layer to fabricate all-polymer solar cells.The blend morphology variance processed with pure and mixed solvents,and the related photovoltaic performance,are investigated in detail.It is found that,due to its low surface energy,a thin P3HT enrichment layer on the top surface of the active layer greatly increases bimolecular recombination and results in S-kinks of the illuminated current density-voltage curves.With the incorporation of p-xylene(a marginal solvent of P3HT)in the blend solution,the P3HT enrichment atop the active layer surface is effectively decreased because the high boiling-point p-xylene suppresses the diffusion of P3HT chains toward the top surface during the film-drying process.The bimolecular recombination was thus improved and the S-kinks of the photovoltaic curves were completely removed.The overall power conversion efficiencies of the devices are strongly boosted(from 0.88%to 1.41%)when chlorobenzene:p-xylene mixed solvent is used to replace pure chlorobenzene.展开更多
基金financially supported by Ministry of Science and Higher Education of the Russian Federation.
文摘A new principle for producing fire-resistant polymer materials with increased deformation properties using a flame retardant not as a heterogeneous additive,but as a thermoplastic flame retardant in a hybrid polymer mixture with a polyhydrocarbon is considered.Hybrid polymer blends of low-molecular ammonium polyphosphate(APP)with an ethylene-vinyl acetate copolymer(EVA)with an APP content of 80 wt%with enhanced deformation properties were obtained by extrusion mixing at various temperatures in the range from 200°C to 250°C.A chemical scheme for the transformations of the components during the formation of the composite is proposed.X-ray diffraction analysis showed the formation of new crystalline structures of APP.The phase structure of the systems corresponding to the model of a dispersed-filled composite in which EVA plays the role of a matrix,determining the deformation of the mixture,and the filler is ammonium polyphosphate,was studied by scanning electron microscopy(SEM).The method of FTIR microscopy showed chemical interactions between EVA and APP with the formation of amide groups.The conditions for obtaining compositions characterized by heat resistance of 210°C,oxygen index of 55 and ultimate elongation at drawing of 213%were established.
基金financially supported by the National Natural Science Foundation of China(Nos.22341304,22303100 and 12205270)the National Key R&D Program of China(Nos.2023YFA1008800 and 2020YFA0713601)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDC0180303)。
文摘The equilibrium dynamics and nonlinear rheology of unentangled polymer blends remain inadequately understood,especially regarding the influence of short-chain matrix length N_(S) on the structure and rheological behavior of dispersed long chains.Using molecular dynamics simulations based on the Kremer-Grest model,we systematically explore the N_(S)-dependence of static conformations,equilibrium dynamics,and nonlinear shear responses in unentangled long-chain/short-chain polymer blends.Our results demonstrate a decoupling between the static and dynamic sensitivity to N_(S):while the static chain size,R_g,follows Flory theory with slight swelling at small N_(S) due to incomplete excluded volume screening,the diffusion coefficient,D,and the relaxation time,τ_(0),exhibit a strong,non-monotonic N_(S)-dependence,transitioning from monomeric friction dominance at small N_(S) to collective segmental rearrangement at large N_(S).Additionally,we observe partial decoupling between the viscous and normal stress responses:while the zero-shear viscosity,η,is strongly N_(S)-dependent,the first and second normal stress coefficients,Ψ_(1) and Ψ_(2),collapse onto universal curves when scaled by the dimensionless shear rate,γτ_(0),suggesting a common mechanism of orientation and stretching.Under shear,long chains compress in the vorticity direction λ_(z)~Wi^(-0.2),which reduces collision frequency and contributes to shear thinning,while the scaling of weaker orientation resistance m_(G)~Wi^(0.35)reflects hydrodynamic screening by the short-chain matrix.These findings highlight the limitations of single-chain models and emphasize the necessity of considering N_(S)-dependent matrix dynamics and flow-induced structural changes in understanding the rheology of unentangled polymer blends.
基金supported by the National Natural Science Foundation of China(No.52173017)the Project of Introducing Urgently Needed and Scarce Talents in Key Supported Regions of Shandong Province in 2024.
文摘High-entropy polymer blends composed of polypropylene(PP),polystyrene(PS),polyamide 6(PA6),poly(lactic acid)(PLA),and styrene-ethylene-butylene-styrene(SEBS)were successfully fabricated using maleic anhydride-grafted SEBS(SEBS-g-MAH)as a compatibilizer.Dynamic mechanical analysis(DMA),differential scanning calorimetry(DSC),scanning electron microscopy(SEM),and mechanical testing demonstrated that SEBS-g-MAH significantly enhanced the compatibility between the polar(PA6,PLA)and nonpolar(PP,PS,SEBS)components.The compatibilizer effectively refined the microstructure,substantially reduced the domain sizes,and blurred the phase boundaries,indicating enhanced interfacial interactions among all the components.The optimal compatibilizer content(15 wt%)notably increased tensile ductility(elongation at break from 5.0%to 23.7%)while maintaining balanced crystallization behavior,despite slightly decreasing modulus.This work not only demonstrates the broad applicability of high-entropy polymer blends as a sustainable strategy for converting complex,unsorted plastic waste into high-performance value-added materials that significantly contribute to plastic upcycling efforts,but also highlights intriguing physical phenomena emerging from such complex polymer systems.
基金The authors thank the National Natural Science Foundation of China(No.51973193)the State Key Laboratory of Chemical Engineering(No.SKL-ChE-13D)for their financial support.
文摘Immiscible polymer blends are an important family of polymer materials.The interfacial thickness between different phases is a very important parameter that dictates,to a great extent,the morphology and properties of such a blend.This work explores and optimizes an up-to-date atomic force microscopy(AFM)of type NanoIR2^(TM) system in order to quantitatively measure the interfacial thickness of immiscible polymer blends.This system is equipped with two nano-probes capable of detecting the response of a material to an infrared pulse called AFM-infrared spectroscopy mode(AFM-IR)or conducting resonance called AFM-Lorentz Contact Resonance mode(AFM-LCR),respectively.Its potential for quantitatively measuring the interfacial thickness of immiscible polymer blends is evaluated using blends composed of polyamide 6(PA6)and polyolefin elastomer(POE)in the presence or absence of a POE containing maleic anhydride(POE-g-MAH)as a compatibilizer.Surface roughness affects adversely the signal intensity and consequently an accurate measurement of the interfacial thickness.Optimum sample surface preparation procedures are proposed.
基金Supported by the National Natural Science Foundation of China （20976044 20736002）
文摘The effects of blend composition and micro-phase structure on the mechanical behavior of A/B polymer blend film are studied by coupling the Monte Carlo(MC) simulation of morphology with the lattice spring model(LSM) of micro mechanics of materials.The MC method with bond length fluctuation and cavity diffusion algorithm on cubic lattice is adopted to simulate the micro-phase structure of A/B polymer blend.The information of morphology and structure is then inputted to the LSM composed of a three-dimensional network of springs to obtain the mechanical properties of polymer blend film.Simulated results show that the mechanical response is mainly affected by the density and the composition of polymer blend film through the morphology transition.When a force is applied on the outer boundary of polymer blend film,the vicinity of the inner cavities experiences higher stresses and strains responsible for the onset of crack propagation and the premature failure of the entire system.
基金financially supported by the National Natural Science Foundation of China(No.51221002)
文摘Poly（vinylidene fluoride） （PVDF） and poly（butylene succinate-co-24 mol% hexamethylene succinate） （PBHS）, both crystalline polymers, formed melt-miscible crystalline/crystalline polymer blends. Both the characteristic diffraction peaks and nonisothermal melt crystallization peak of each component were found in the blends, indicating that PVDF and PBHS crystallized separately. The crystalline morphology and crystallization kinetics of each component were studied under different crystallization conditions for the PVDF/PBHS blends. Both the spherulitic growth rates and overall isothermal melt crystallization rates of blended PVDF decreased with increasing the PBHS composition and were lower than those of neat PVDF, when the crystallization temperature was above the melting point of PBHS component. The crystallization mechanism of neat and blended PVDF remained unchanged, despite changes of blend composition and crystallization temperature. The crystallization kinetics and crystalline morphology of neat and blended PBHS were further studied, when the crystallization temperature was below the melting point of PBHS component. Relative to neat PBHS, the overall crystallization rates of the blended PBHS first increased and then decreased with increasing the PVDF content in the blends, indicating that the preexisting PVDF crystals may show different effects on the nucleation and crystal growth of PBHS component in the crystalline/crystalline polymer blends.
文摘Various viscosity-composition curves of polymer blends are summarized in eight groups. To represent these curves. 'sub-cluster equations' are derived on the basis of so called 'sub-cluster theoryThe essential concepts of sub-cluster theory and the derivation of those 'Sub-cluster equations' are briefly introduced.
基金the National Natural Science Foundation of China (Nos. 52173076 and 52042302)China Postdoctoral Science Foundation (No. 2021M701825)+1 种基金Tsinghua-Foshan Innovation Special Fund (TFISF) (No. 2021THFS0212)Joint Agency Affiliate Projects of China Petroleum & Chemical Corporation (No. 20212930037)。
文摘Mixing two or more polymers to produce the“polymer alloy”is one of the most versatile and economical strategies for developing new polymeric materials.The compatibility between polymer components largely determines the comprehensive performance of polymer blend.More recently,a type of unique surface partitioned materials,Janus particles,has been proposed to act as a novel interfacial compatibilizer for polymer blends.Such Janus particles integrates the amphipathicity of diblock copolymer and interfacial stabilization of nanoparticles,displaying a significant superiority in comparison with molecular compatibilizers for a wide range of polymer blends.In this review,we mainly focus on the compatibilizing effects of Janus nanofillers of various morphologies,including spherical,snowman-like,and two-dimensional nanosheets,on polymer blends.We shed light on the impacts of compatibilization of Janus particles on phase morphologies,mechanical properties,and functionalities of polymer blends.This review could provide a guidance for designing an effective Janus particle compatibilizer to develop high-performance polymer blends.
基金financially supported by the National Basic Research Program of China(973 Program,2012CB821500)supported by the National Natural Science Foundation of China(Nos.21222407,21074137 and 50930001)
文摘The effect of silica nanoparticles on the morphology of （10/90 wt%） PDMS/PBD blends during the shear induced coalescence of droplets of the minor phase at low shear rate was investigated systematically in situ by using an optical shear technique. Two blending procedures were used： silica nanoparticles were introduced to the blends by pre-blending silica particles first in PDMS dispersed phase （procedure 1） or in PBD matrix phase （procedure 2）. Bimodal or unimodal droplet size distributions were observed for the filled blends during coalescence, which depend not so much on the surface characteristics of silica but mainly on blending procedure. For pure （10/90 wt%） PDMS/PBD blend, the droplet size distribution exhibits bimodality during the early coalescence. When silica nanoparticles （hydrophobic and hydrophilic） were added to the blends with procedure l, bimodal droplet size distributions disappear and unimodal droplet size distributions can be maintained during coalescence; the shape of the different peaks is invariably Gaussian. Simultaneously, coalescence of the PDMS droplets was suppressed efficiently by the silica nanoparticles. It was proposed that with this blending procedure the nanoparticles should be mainly kinetically trapped at the interface or in the PDMS dispersed phase, which provides an efficient steric barrier against coalescence of the PDMS dispersed phase. However, bimodal droplet size distributions in the early stage of coalescence still occur when incorporating silica nanoparticles into the blends with procedure 2, and then coalescence of the PDMS droplets cannot be suppressed efficiently by the silica nanoparticles. It was proposed that with this blending protocol the nanoparticles should be mainly located in the PBD matrix phase, which leads to an inefficient steric barrier against coalescence of the PDMS dispersed phase; thus the morphology evolution in these filled blends is similar to that in pure blend and bimodal droplet size distributions can be observed during the early coalescence. These results imply that exploiting non-equilibrium processes by varying preparation protocol may provide an elegant route to regulate the temporal morphology of the filled blends during coalescence.
基金the Excellent Young Teachers Programthe Research Foundation for Doctoral Project of the Ministry of Education of China.
文摘Low cycle fatigue crack propagation (FCP) behavior of two PC/ABSblends with a weight ra- tio of PC to ABS being 80/20 and 60/40,respectively, is investigated. Experiments are carried out by usingstandard compact tension (CT) specimens. The fracture surfaces areexamined with a scanning electron mi- croscope (SEM). It is shownthat the FCP resistance of PC/ABS blend with 20/100 ABS particles ishigher than that of PC/ABS blend with 40/100 ABS particles. It isfound that proper ABS particle content can result in the tougheningof PC/ABS blends through particle cavitation and shear yielding inmatrix.
基金This work was supported by research grants from the National Natural Science Foundation of China and The Special Funds for Major State Basic Research Projects (G199906408).
文摘A fast coalescence mechanism is proposed to account for the wall effect on the formation of gradient morphology in phase separated polymer blends during quiescent annealing. The existence of solid wall with high polarity is believed to change the potential field around the dispersed particles near the wall. This additional potential interaction between the solid wall and the dispersed particles causes faster coalescence of the dispersed particles near the wall than in the bulk. The gradient phase morphology thus formed can be predicted by combining the wall-particle interaction and the touch-coalescence mechanism. The effect of interfacial tension on the gradient morphology is also discussed.
基金supported by the National Natural Science Foundation of China(Nos.51873111,51721091)the Scientific Research Foundation of Sichuan Province(No.2018HH0001)+1 种基金the Programme of Introducing Talents of Discipline to Universities(No.B13040)the Graduate Innovation Foundation of Sichuan University(No.2018YJSY088).
文摘Silica rods with homogeneous(hydrophilic or hydrophobic)and amphiphilic surface properties were synthesized and their efficiencies in suppressing the flow-induced droplet coalescence of immiscible polyisobutylene(PIB)/polydimethylsiloxane(PDMS)blends were evaluated via in situ visualization technique.The flow-induced coalescence behavior of blends was found to strongly depend on the surface nature and concentration of silica rods added as well as the blend ratio.While a trace amount of rods promoted coalescence,all kinds of rods demonstrated a morphology refinement effect at high rod concentrations.Good compatibilization effects were obtained at high rod concentrations,especially for hydrophilic and amphiphilic rods.Based on confocal laser scanning microscopy results,these phenomena observed were interpreted reasonably in terms of the selective distribution and aggregation of silica rods,which were suggested to be decisive for the stabilization mechanism and efficiency of these rods.
文摘Series of PVC/ABS and PVC/SBS blends of composition 20/ 80. 40/ 60, 60 / 40 and 80 / 20were prepared in a screw extruder. The phase morphology, miscibility and rheological behaviour of two systems were investigated. The viscosity-composition plots were represented by sub-cluster equation, the various differences between two systems are interpreted with the equation parameters
文摘Compatibility of poly (vinyl acetate) (PVAc) with poly (methyl methacrylate) (PMMA) mixtures has been studied by using nuclear magnetic relaxation, differential scanning calorimeter and small-angle X-ray scattering techniques. The nuclear magnetic relaxation time T_1's were measured as a function of composition in blends of PMMA and PVAc prepared from chloroform solution. The results show that the system is miscible for casting from chloroform solution.
基金China Postdoctoral Science Foundation (2005037463)
文摘The polymer blend technique is a novel method to produced carbon nanofibers. In this paper, we have prepared fine carbon fibers and porous carbon materials by this technique, and we will discuss the experiment results by means of SEM, TGA, Element Analysis, etc.
基金a seed grant from IIT Delhi(SGNF148)supported by the JST-ERATO Yamauchi Materials SpaceTectonics Project(JPMJER2003)+2 种基金the ARC Australian Laureate Fellowship(FL230100095)the UQ-Yonsei International Joint Research Projectthe support from JSPS Postdoctoral Fellowships for Research in Japan。
文摘Commercial-level sodium metal batteries require electrolytes with high ionic mobility and excellent thermo-mechanical and electrochemical stability.Conventional flammable liquid electrolytes,prone to dendrite growth and unstable interfacial reactions,rarely perform beyond coin-cell demonstrations.To address these shortcomings,a multifunctional composite quasi-solid polymer electrolyte(QSPE)that incorporates boron nitride(BN)as an engineered filler in a highly conductive polymer blend system has been developed.The optimized formation(15BN QSPE)delivers a room-temperature ionic conductivity of 2.15 m S cm^(-1)and a sodium-ion transference number of 0.80.Molecular dynamics simulations elucidate the coordination environment and show improved transport in the presence of BN.BN is chemically active and bifunctional:boron acts as an electron acceptor,interacting with solvents and macromolecules,while nitrogen coordinates with sodium ions,tailoring the solvation environment and transport pathways to promote efficient ion migration.The 15BN QSPE is self-extinguishing,resists oxidative thermal degradation,and enables stable cycling in symmetric sodium cells for>1400 h at0.5 m A cm^(-2).A Prussian blue full cell achieves>1500 stable cycles at 1C with -99% Coulombic efficiency in coin-cell configuration.A two-layer pouch cell with dual 15BN QSPE layers delivers 600 stable cycles at 0.125C and withstands rigorous mechanical abuse.These results position 15BN QSPE as a scalable,highperformance electrolyte offering enhanced safety and efficiency for next-generation sodium metal batteries.
基金support from the National Natural Science Foundation of China(22322103,and 22271057)State Key Laboratory of Molecular Engineering of Polymers,Department of Macromolecular Science,Fudan University,Shanghai Pilot Program for Basic Research-Fudan University(21TQ1400100,25TQ005)Shanghai Titan Natural Science Development Foundation.
文摘The visualization of phase separation in immiscible polymer blends holds significant industrial and academic relevance,as the resultant phase architecture governs the macroscopic properties and ultimate performance of blended materials.To address this challenge,a dual-fluorophore labeling strategy is introduced,enabling high-contrast differentiation of polymeric phases.By covalently tethering two spectrally orthogonal fluorophores to their respective polymer components,unambiguous spatial resolution of blend morphologies is achieved through laser scanning confocal microscopy(LSCM).When compatibilizers are incorporated,LSCM imaging reveals fundamentally reconfigured phase architectures compared to uncompatibilized systems.This fluorescence-based approach permits direct assessment of blend compatibility through quantitative evaluation of interfacial domain coherence and phase dispersion homogeneity.The methodology demonstrates exceptional versatility,successfully resolving phase boundaries in both chemically dissimilar systems(e.g.,polylactic acid[PLA]/poly(butylene adipate-co-terephthalate)[PBAT]blends with pronounced polarity disparities)and structurally congruent polymers(e.g.,polyethylene[PE]/polypropylene[PP]variants).The universal applicability stems from the substantial spectral distinction between fluorophore-labeled polymers,independent of variations in polymer polarity or structural configurations.
文摘Polyethylene oxide （PEO）-polyvinylpyrrolidone （PVP） blended Na＋ ion conducting solid polymeric membranes： （1-x） [75PEO：25NaPO3] ＋ x PVP, where 0 〈 x 〈 12 wt%, are reported. The polymeric blending was done using a solvent- free hot-press method. Two orders of conductivity enhancement （σca. 1.07× 10^-5 S·cm^-1） have been achieved with 3 wt% of PVP （i.e. the composition： [97（75PEO：25NaPO3） ＋ 3PVP]）, from that of the pure host： （75PEO：25NaPO3）. The conductivity enhancement in PEO-PVP blended solid polymeric membranes have been explained by the ionic conductivity, ionic mobility and mobile ion concentration measurements. Materials characterization and polymer-salt complexation were done with the help of X-ray diffraction （XRD）, scanning electron microscopy （SEM）, differential scanning calorimetry （DSC） and thermo gravimetric analysis （TGA） studies. The temperature dependent conductivity studies have also been done to compute the activation energy （Ea） values from lgσ-1/TArrhenius plots. A solid state polymeric battery was fabricated by using optimum conducting composition of solid polymer electrolyte （SPE OCC）, and some important cell parameters were also calculated from the discharge profile of the cell.
基金financially supported by the National Natural Science Foundation of China(No.51173095)
文摘The diffusion and subsequent copolymerization of styrene （St）/butyl methacrylate （BMA） mixed monomers in iPP pellets to prepare copolymer nanoblends were investigated. The diffusion step was carded out at 90 ℃ for 2 h in water, and the copolymerization was initiated by the addition of BPO with the aid of a small amount of St. The diametrical distributions of both St and BMA units and their ratio St/BMA were investigated by micro FTIR. Both St and BMA can diffuse into the centres of iPP pellets. The diametrical distribution of St/BMA ratio is constant in all the copolymer blends. The copolymer composition depends on the comonomer feed ratio. The molecular weights of the copolymers were measured by GPC after extraction with tetrahydrofuran. The phase morphology of the copolymer blends was investigated by FESEM, showing the average particle sizes of less than 100 nm. DSC measurements show that the diffusion and subsequent copolymerization of St/BMA monomers only occur in the amorphous regions of iPP pellets.
基金supported by the National Basic Research Program of China(2014CB643504)the National Natural Science Foundation of China(51325303,51273193,21334006)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB12030200)
文摘A polymer blend comprising poly(3-hexylthiophene)(P3HT)donor and poly[2,7-(9,9′-octyl-fluorene)-alt-5,5-(4′,7′-di-2-thienyl-5′,6′-bis(hexyloxy)-2′,1′,3′-benzothiadiazole)](PFDTBT-OC6)acceptor is used as the active layer to fabricate all-polymer solar cells.The blend morphology variance processed with pure and mixed solvents,and the related photovoltaic performance,are investigated in detail.It is found that,due to its low surface energy,a thin P3HT enrichment layer on the top surface of the active layer greatly increases bimolecular recombination and results in S-kinks of the illuminated current density-voltage curves.With the incorporation of p-xylene(a marginal solvent of P3HT)in the blend solution,the P3HT enrichment atop the active layer surface is effectively decreased because the high boiling-point p-xylene suppresses the diffusion of P3HT chains toward the top surface during the film-drying process.The bimolecular recombination was thus improved and the S-kinks of the photovoltaic curves were completely removed.The overall power conversion efficiencies of the devices are strongly boosted(from 0.88%to 1.41%)when chlorobenzene:p-xylene mixed solvent is used to replace pure chlorobenzene.
