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
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
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
The miscibility and structure of A-B copolymer/C homopolymer blends with special interactions were studied by aMonte Carlo simulation in two dimensions. The interaction between segment A and segment C was repulsive, w...The miscibility and structure of A-B copolymer/C homopolymer blends with special interactions were studied by aMonte Carlo simulation in two dimensions. The interaction between segment A and segment C was repulsive, whereas it wasattractive between segment B and segment C. In order to study the effect of copolymer chain structure on the morphologyand structure of A-B copolymer/C homopolymer blends, the alternating, random and block A-B copolymers were introducedinto the blends, respectively. The simulation results indicated that the miscibility of A-B block copolymer/C homopolymerblends depended on the chain structure of the A-B copolymer. Compared with alternating or random copolymer, the blockcopolymer, especially the diblock copolymer, could lead to a poor miscibility of A-B copolymer/C homopolymer blends.Moreover, for diblock A-B copolymer/C homopolymer blends, obvious self-organized core-shell smicture was observed inthe segment B composition region from 20% to 60%. However if diblock copolymer composition in the blends is less than40%, obvious self-organized core-shell structure could be formed in the B-segment component region from 10 to 90%.Furthermore, computer statistical analysis for the simulation results showed that the core sizes tended to increasecontinuously and their distribution became wider with decreasing B-segment component.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 performance and morphology stability of polymer bulk heterojunetion solar cells based on poly（3-hexylthiophene） （P3HT） as the donor and indene-C6o bisadduct （ICBA） or methanofullerene [6,6]-phenyl C61-butyri...The performance and morphology stability of polymer bulk heterojunetion solar cells based on poly（3-hexylthiophene） （P3HT） as the donor and indene-C6o bisadduct （ICBA） or methanofullerene [6,6]-phenyl C61-butyric acid methyl ester （PCBM） as the aeceptor are compared. Effect of the different donor and aeeeptor weight ratios on photo- voltaic performance of the P3HT：ICBA device is studied. The optimal device achieved power conversion emeiency of 5.51~o with dso of l0.86mA/cm2, Voc of 0.83 V, and fill factor （FF） of 61.1 % under AM 1.5G （lOOmW/cm2） simulated solar illumination. However, the stability measurement shows that cells based on P3HT：ICBA are less stable than those of the device based on P3HT：PCBM. Atomic force microscope results reveal that the morphol- ogy of the P3HT：ICBA film changed considerably during the storage periods due to unstable interpenetrating D-A network. This observation can be explained by the fact that there is lack of intermolecular hydrogen bonds in the P3HT：ICBA system. However, in the P3HT：PCBM system the molecules in the blend film are firmly held together in the solid state by means of intermoleeular hydrogen bonds originating from C-H. ~. Os bonds （where Os comes from the singly-bonded 0 atom of PCBM）, forming a stable three-dimensional network. The measured PL decay lifetimes for P3HT：PCBM and P3HT：ICBA systems are 33.66 ns and 35.34 ns, respectively, indicating that the P3HT：ICBA system has a less efficient exciton separation eftleiency than that of P3HT：PCBM, which may result in the interracial photogenerated charges accumulated on the D： A interface. Such progressive phase segregation between P3HT and ICBA eventually leads to the degradation in performance and deteriorates the stability of the device. We also present an approach to enhance the stability of P3HT：ICBA systems by adding PCBM as the second acceptor. Our results show that by carefully tuning the contents of PCBM as the second acceptor, more stable polymer solar cells can be obtained.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
A poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide)(PLLA-PEG-PLLA)block copolymer has great potential for use as a flexible bioplastic.Highly flexible bioplastics are required for flexible packaging applicatio...A poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide)(PLLA-PEG-PLLA)block copolymer has great potential for use as a flexible bioplastic.Highly flexible bioplastics are required for flexible packaging applications.In this work,a PEG was incorporated into block copolymer as a plasticizer by solvent casting.PLLA-PEG-PLLA/PEG blends with different blend ratios were prepared,and the plasticizing effect and miscibility of PEG in block copolymer were intensively investigated compared to PLLA/PEG blends.The results indicated that the PEG was an effective plasticizer for the block copolymer.The blending of PEG decreased glass-transition temperature and accelerated the crystallization of both the PLLA and PLLA-PEG-PLLA matrices.The PEG was completely miscible when blended with block copolymer and it improved thermal stability of the block copolymer matrix but not of the PLLA matrix.Film extensibility of PLLA-PEG-PLLA/PEG blends steadily increased as the PEG ratio increased.These non-toxic and highly flexible PLLA-PEG-PLLA/PEG bioplastics are promising candidates for several applications such as biomedical devices,tissue scaffolds and packaging materials.展开更多
Hybrid organic-inorganic perovskites have been the subject of recent intense interest due to advances in photovoltaic and other optoelectronic applications. However, their poor stability limits commercial market appli...Hybrid organic-inorganic perovskites have been the subject of recent intense interest due to advances in photovoltaic and other optoelectronic applications. However, their poor stability limits commercial market application We enhance water stability by post treatment preparation of hybrid metal halide perovskite nanocrystal-embedded polymethylmethacrylate （PM- MA） blend films. Through blending process without any cleaning of nanocrystals, crystalline hybrid organic-inorganic perovs-kite nanocrystals were incorporated into PMMA matrix with well-dispersion Passivation of PMMA on the surface of the per-ovskite nanocrystals results in decreased traps and a long photoluminescence （PL） lifetime despite the bromine vacancies in the crystal lattice. Moreover, such color purity and inherent high transmittance for fluorescence emission of perovskite nanocrystals will endow the films with promising potentials in diverse practice photonic applications.展开更多
In this work, polypropylene (PP)/polystyrene (PS) blends with different organoclay concentrations were prepared via melt compounding. Differing from the results of previous reports, the organoclay platelets are mostly...In this work, polypropylene (PP)/polystyrene (PS) blends with different organoclay concentrations were prepared via melt compounding. Differing from the results of previous reports, the organoclay platelets are mostly located in the dispersed PS phase instead of the interface. The dimensions of the dispersed PS droplets are greatly reduced and apparent compatibilization effect still exists, which cannot be explained by the traditional compatibilization mechanism. A novel compatibilization mecha- nism, "cutting" to apparently compatibilize the immiscible PP/PS blends was proposed. The organoclay platelets tend to form a special "knife-like structure" in the PS domain under the shear stress of the continuous PP phase during compounding. The "clay knife" can split the dispersed PS domain apart and lead to the dramatic reduction of the dispersed domain size.展开更多
Evolution and fractal character of the phase morphology of high impact polystyrene/poly（cis-butadiene） rubber （HIPS/PcBR） blends during melting and mixing were investigated using scanning electron microscopy （SEM...Evolution and fractal character of the phase morphology of high impact polystyrene/poly（cis-butadiene） rubber （HIPS/PcBR） blends during melting and mixing were investigated using scanning electron microscopy （SEM）. The characteristic length L was defined as the size of particles of the dispersed phase in blends. Different fractal dimensions, Df and Din, were introduced to study the distribution width of phase dimensions in the dimensionless region and the uniformity of the spatial distribution of particles, respectively. The results showed that the average characteristic length Lm and Df increase as the volume fraction of the dispersed phase increases, when the volume fraction of the dispersed phase is lower than 50%. In other words, the size of particles increases and their distribution in the dimensionless region becomes more uniform. Meanwhile, the uniformity of the spatial distribution becomes more perfect as the volume fraction increases. At a certain composition, Lm decreases in the initial stage of the mixing and levels off in the late stage. In the initial stage, Df becomes large rapidly with the process of blending, which means that the distribution of L in the dimensionless region becomes more uniform. Meanwhile, the spatial distribution tends to be ideal rapidly in the early stage and fluctuates in a definite range in the late stage of the mixing.展开更多
This paper mainly introduced the preparation of silk fibroin membranes and their structural change characteristics.Silk fibroin membranes can be used as tissue engineering materials,enzyme-immobilizing membranes,biose...This paper mainly introduced the preparation of silk fibroin membranes and their structural change characteristics.Silk fibroin membranes can be used as tissue engineering materials,enzyme-immobilizing membranes,biosensors and drug controlled-release membranes and other different materials.They have excellent characteristics such as non-toxic,non-polluting and degradable,and thus have broad application prospects.展开更多
The main objective was to study the anticorrosion performance of poly（o-toluidine）/nano ZrO2/epoxy composite coating.Poly（o-toluidine）/nano ZrO2 composite was prepared by in situ polymerization of o-toluidine mono...The main objective was to study the anticorrosion performance of poly（o-toluidine）/nano ZrO2/epoxy composite coating.Poly（o-toluidine）/nano ZrO2 composite was prepared by in situ polymerization of o-toluidine monomer in the presence of nano ZrO2 particles.Fourier transformation infrared spectroscopy（FT-IR）,UV-visible spectroscopy（UV-vis）,X-ray diffraction（XRD）,Scanning electron microscopy（SEM）,and Thermogravimetric analysis（TGA） were used to characterize the composition and structure of the composite.Poly（o-toluidine）/nano ZrO2 composite was mixed with epoxy resin through a solution blending method and the three components poly（o-toluidine）/nano ZrO2/epoxy composite coating was coated onto the surface of steel sample by the brush coating method.The anticorrosion performance of poly（o-toluidine）/nano ZrO2/epoxy composite coating on steel sample was studied by polarization curve and electrochemical impendence spectroscopy in 3.5% Na Cl solution as corrosion environment and also compared with that of poly（o-toluidine）/epoxy composite coating and pure epoxy coating.It was observed that the composite coating containing poly（otoluidine）/nano ZrO2 composite has got higher corrosion protection ability than that of poly（o-toluidine）.The electrochemical measurement results demonstrated that poly（o-toluidine） fillers improve the electrochemical anticorrosion performance of epoxy coating and the addition of nano ZrO2 particles increases the tortuosity of the diffusion pathway of corrosive substances.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 miscibility of poly(ethylene terephthalate (ET)- caprolactone (CL) (TCL)/poly(ethylene terephthalate) (PET) blends were examined by Differential Scanning Calorimeter (DSC). In these blends, a miscibility limit spe...The miscibility of poly(ethylene terephthalate (ET)- caprolactone (CL) (TCL)/poly(ethylene terephthalate) (PET) blends were examined by Differential Scanning Calorimeter (DSC). In these blends, a miscibility limit specified by ET content in the TCL was found to be about 70 (wt%). In the blends of TCL/TCL with different ET contents, a miscibility window defined by ET content was also found to range from 82 to 58 (wt%). Based on the experimental miscibility limits and the mean field binary interaction model, the interaction parameter between monomeric units of ET and CL was obtained.展开更多
A high-performance porous carbon material for supercapacitor electrodes was prepared by using a polymer blend method. Phenol-formaldehyde resin and gelatin were used as carbon precursor polymer and pore former polymer...A high-performance porous carbon material for supercapacitor electrodes was prepared by using a polymer blend method. Phenol-formaldehyde resin and gelatin were used as carbon precursor polymer and pore former polymer, respectively. The blends were carbonized at 800℃ in nitrogen. SEM, BET measurement and BJH method reveal that the obtained carbon possesses a mesoporous characteristic, with the average pore size between 3.0 nm and 5.0 nm. The electrochemical properties of supercapacitor using these carbons as electrode material were investigated by cyclic voltammetry and constant current charge-discharge. The results indicate that the composition of blended polymers has a strong effect on the specific capacitance. When the mass ratio of PF to gelatin is kept at 1：1, the largest surface area of 222 m2/g is obtained, and the specific capacitance reaches 161 F/g.展开更多
The transition behaviour of the blends of isotactic polypropylene (i-PP) with ethylene-propylene terpolymer (EPDM) containing 42 wt% propylene was investigated by dynamic mechanical analysis technique (DMA). Owing to ...The transition behaviour of the blends of isotactic polypropylene (i-PP) with ethylene-propylene terpolymer (EPDM) containing 42 wt% propylene was investigated by dynamic mechanical analysis technique (DMA). Owing to its high propylene content, EPDM is compatible with i-PP to some degree. The interaction between the two components was strengthened. As expected, for partially compatible system the glass transition temperature of i-PP in the blends shifted to lower temperature. It was found that there existed two transitions, αEPDM and βEPDM, for the EPDM used in this work. The former was considered to be the glass transition of the random chain segments of EPDM, while the latter the local motion of the long ethylene sequences in EPDM. The unusual transition behaviour of αEPDM in the blends was explained in terms of the greater thermal expansion of EPDM and the compatibility of the two components. On the other hand, the βEPDM changed with the composition of the blends in a regular manner.展开更多
Positron annihilation lifetime spectroscopy （PALS） is a powerful technique for the study of free volume in polymers. The lifetime of ortho-positronium （o-Ps）, a bound state of an electron and a positron, can be us...Positron annihilation lifetime spectroscopy （PALS） is a powerful technique for the study of free volume in polymers. The lifetime of ortho-positronium （o-Ps）, a bound state of an electron and a positron, can be used to assess the pore size, while the intensity can be used to characterize the number of pores. Based on the values of the long-lived o-Ps components in the lifetime spectra, the radii and fractional free volumes of sulfonated poly （2,6-dimethyl-1,4- phenyleneoxide） （SPPO） membranes with added LiCl and SPPO-PES （Polyethersulfone） blend were compared. Free volume radii in both kinds of membranes are discussed.展开更多
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.
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 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This work was supported by the National Natural Science Foundation of China (20023003, 50027001, 29704008, 20074037, 50073023 and 50290090) and subsidized by the Special Funds for Major Basic Research projects (G1999064800) and the Special Pre-Funds for
文摘The miscibility and structure of A-B copolymer/C homopolymer blends with special interactions were studied by aMonte Carlo simulation in two dimensions. The interaction between segment A and segment C was repulsive, whereas it wasattractive between segment B and segment C. In order to study the effect of copolymer chain structure on the morphologyand structure of A-B copolymer/C homopolymer blends, the alternating, random and block A-B copolymers were introducedinto the blends, respectively. The simulation results indicated that the miscibility of A-B block copolymer/C homopolymerblends depended on the chain structure of the A-B copolymer. Compared with alternating or random copolymer, the blockcopolymer, especially the diblock copolymer, could lead to a poor miscibility of A-B copolymer/C homopolymer blends.Moreover, for diblock A-B copolymer/C homopolymer blends, obvious self-organized core-shell smicture was observed inthe segment B composition region from 20% to 60%. However if diblock copolymer composition in the blends is less than40%, obvious self-organized core-shell structure could be formed in the B-segment component region from 10 to 90%.Furthermore, computer statistical analysis for the simulation results showed that the core sizes tended to increasecontinuously and their distribution became wider with decreasing B-segment component.
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Supported by the Tianjin Natural Science Foundation under Grant Nos 13JCYBJC18900 and 13JCZDJC26700the National High Technology Research and Development Program of China under Grant No 2013AA014201
文摘The performance and morphology stability of polymer bulk heterojunetion solar cells based on poly（3-hexylthiophene） （P3HT） as the donor and indene-C6o bisadduct （ICBA） or methanofullerene [6,6]-phenyl C61-butyric acid methyl ester （PCBM） as the aeceptor are compared. Effect of the different donor and aeeeptor weight ratios on photo- voltaic performance of the P3HT：ICBA device is studied. The optimal device achieved power conversion emeiency of 5.51~o with dso of l0.86mA/cm2, Voc of 0.83 V, and fill factor （FF） of 61.1 % under AM 1.5G （lOOmW/cm2） simulated solar illumination. However, the stability measurement shows that cells based on P3HT：ICBA are less stable than those of the device based on P3HT：PCBM. Atomic force microscope results reveal that the morphol- ogy of the P3HT：ICBA film changed considerably during the storage periods due to unstable interpenetrating D-A network. This observation can be explained by the fact that there is lack of intermolecular hydrogen bonds in the P3HT：ICBA system. However, in the P3HT：PCBM system the molecules in the blend film are firmly held together in the solid state by means of intermoleeular hydrogen bonds originating from C-H. ~. Os bonds （where Os comes from the singly-bonded 0 atom of PCBM）, forming a stable three-dimensional network. The measured PL decay lifetimes for P3HT：PCBM and P3HT：ICBA systems are 33.66 ns and 35.34 ns, respectively, indicating that the P3HT：ICBA system has a less efficient exciton separation eftleiency than that of P3HT：PCBM, which may result in the interracial photogenerated charges accumulated on the D： A interface. Such progressive phase segregation between P3HT and ICBA eventually leads to the degradation in performance and deteriorates the stability of the device. We also present an approach to enhance the stability of P3HT：ICBA systems by adding PCBM as the second acceptor. Our results show that by carefully tuning the contents of PCBM as the second acceptor, more stable polymer solar cells can be obtained.
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financially supported by Mahasarakham University。
文摘A poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide)(PLLA-PEG-PLLA)block copolymer has great potential for use as a flexible bioplastic.Highly flexible bioplastics are required for flexible packaging applications.In this work,a PEG was incorporated into block copolymer as a plasticizer by solvent casting.PLLA-PEG-PLLA/PEG blends with different blend ratios were prepared,and the plasticizing effect and miscibility of PEG in block copolymer were intensively investigated compared to PLLA/PEG blends.The results indicated that the PEG was an effective plasticizer for the block copolymer.The blending of PEG decreased glass-transition temperature and accelerated the crystallization of both the PLLA and PLLA-PEG-PLLA matrices.The PEG was completely miscible when blended with block copolymer and it improved thermal stability of the block copolymer matrix but not of the PLLA matrix.Film extensibility of PLLA-PEG-PLLA/PEG blends steadily increased as the PEG ratio increased.These non-toxic and highly flexible PLLA-PEG-PLLA/PEG bioplastics are promising candidates for several applications such as biomedical devices,tissue scaffolds and packaging materials.
文摘Hybrid organic-inorganic perovskites have been the subject of recent intense interest due to advances in photovoltaic and other optoelectronic applications. However, their poor stability limits commercial market application We enhance water stability by post treatment preparation of hybrid metal halide perovskite nanocrystal-embedded polymethylmethacrylate （PM- MA） blend films. Through blending process without any cleaning of nanocrystals, crystalline hybrid organic-inorganic perovs-kite nanocrystals were incorporated into PMMA matrix with well-dispersion Passivation of PMMA on the surface of the per-ovskite nanocrystals results in decreased traps and a long photoluminescence （PL） lifetime despite the bromine vacancies in the crystal lattice. Moreover, such color purity and inherent high transmittance for fluorescence emission of perovskite nanocrystals will endow the films with promising potentials in diverse practice photonic applications.
文摘In this work, polypropylene (PP)/polystyrene (PS) blends with different organoclay concentrations were prepared via melt compounding. Differing from the results of previous reports, the organoclay platelets are mostly located in the dispersed PS phase instead of the interface. The dimensions of the dispersed PS droplets are greatly reduced and apparent compatibilization effect still exists, which cannot be explained by the traditional compatibilization mechanism. A novel compatibilization mecha- nism, "cutting" to apparently compatibilize the immiscible PP/PS blends was proposed. The organoclay platelets tend to form a special "knife-like structure" in the PS domain under the shear stress of the continuous PP phase during compounding. The "clay knife" can split the dispersed PS domain apart and lead to the dramatic reduction of the dispersed domain size.
基金This work was supported by the National Natural Science Foundation of China (No. 50390090).
文摘Evolution and fractal character of the phase morphology of high impact polystyrene/poly（cis-butadiene） rubber （HIPS/PcBR） blends during melting and mixing were investigated using scanning electron microscopy （SEM）. The characteristic length L was defined as the size of particles of the dispersed phase in blends. Different fractal dimensions, Df and Din, were introduced to study the distribution width of phase dimensions in the dimensionless region and the uniformity of the spatial distribution of particles, respectively. The results showed that the average characteristic length Lm and Df increase as the volume fraction of the dispersed phase increases, when the volume fraction of the dispersed phase is lower than 50%. In other words, the size of particles increases and their distribution in the dimensionless region becomes more uniform. Meanwhile, the uniformity of the spatial distribution becomes more perfect as the volume fraction increases. At a certain composition, Lm decreases in the initial stage of the mixing and levels off in the late stage. In the initial stage, Df becomes large rapidly with the process of blending, which means that the distribution of L in the dimensionless region becomes more uniform. Meanwhile, the spatial distribution tends to be ideal rapidly in the early stage and fluctuates in a definite range in the late stage of the mixing.
基金Supported by Chongqing Natural Science Foundation Project(18219)Chongqing Scientific Research Institution Performance Incentive Project(19537,20521)+1 种基金Chongqing Rongchang Agriculture and Animal Husbandry High Tech Industry R&D Special Project(20209)Chongqing Modern Mountain Characteristic Benefit Agriculture(Sericulture)Technology System Diversified Development Research Office(18304).
文摘This paper mainly introduced the preparation of silk fibroin membranes and their structural change characteristics.Silk fibroin membranes can be used as tissue engineering materials,enzyme-immobilizing membranes,biosensors and drug controlled-release membranes and other different materials.They have excellent characteristics such as non-toxic,non-polluting and degradable,and thus have broad application prospects.
基金Funded by the Innovation Project of Guangxi Graduate Education(No.YCSZ2014202)
文摘The main objective was to study the anticorrosion performance of poly（o-toluidine）/nano ZrO2/epoxy composite coating.Poly（o-toluidine）/nano ZrO2 composite was prepared by in situ polymerization of o-toluidine monomer in the presence of nano ZrO2 particles.Fourier transformation infrared spectroscopy（FT-IR）,UV-visible spectroscopy（UV-vis）,X-ray diffraction（XRD）,Scanning electron microscopy（SEM）,and Thermogravimetric analysis（TGA） were used to characterize the composition and structure of the composite.Poly（o-toluidine）/nano ZrO2 composite was mixed with epoxy resin through a solution blending method and the three components poly（o-toluidine）/nano ZrO2/epoxy composite coating was coated onto the surface of steel sample by the brush coating method.The anticorrosion performance of poly（o-toluidine）/nano ZrO2/epoxy composite coating on steel sample was studied by polarization curve and electrochemical impendence spectroscopy in 3.5% Na Cl solution as corrosion environment and also compared with that of poly（o-toluidine）/epoxy composite coating and pure epoxy coating.It was observed that the composite coating containing poly（otoluidine）/nano ZrO2 composite has got higher corrosion protection ability than that of poly（o-toluidine）.The electrochemical measurement results demonstrated that poly（o-toluidine） fillers improve the electrochemical anticorrosion performance of epoxy coating and the addition of nano ZrO2 particles increases the tortuosity of the diffusion pathway of corrosive substances.
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.
文摘The miscibility of poly(ethylene terephthalate (ET)- caprolactone (CL) (TCL)/poly(ethylene terephthalate) (PET) blends were examined by Differential Scanning Calorimeter (DSC). In these blends, a miscibility limit specified by ET content in the TCL was found to be about 70 (wt%). In the blends of TCL/TCL with different ET contents, a miscibility window defined by ET content was also found to range from 82 to 58 (wt%). Based on the experimental miscibility limits and the mean field binary interaction model, the interaction parameter between monomeric units of ET and CL was obtained.
基金Projects(50772033,50972043) supported by the National Natural Science Foundation of ChinaProject(09JJ3095) supported by the Natural Science Foundation of Hunan Province,China+2 种基金Project(09A001) supported by the Scientific Research Fund of Hunan Provincial Education Department,ChinaProject(2010FJ3151) supported by the Science and Research Plan of Hunan Province,ChinaProject supported by the Science and Technology Innovative Research Team in Higher Education Institution of Hunan Province,China
文摘A high-performance porous carbon material for supercapacitor electrodes was prepared by using a polymer blend method. Phenol-formaldehyde resin and gelatin were used as carbon precursor polymer and pore former polymer, respectively. The blends were carbonized at 800℃ in nitrogen. SEM, BET measurement and BJH method reveal that the obtained carbon possesses a mesoporous characteristic, with the average pore size between 3.0 nm and 5.0 nm. The electrochemical properties of supercapacitor using these carbons as electrode material were investigated by cyclic voltammetry and constant current charge-discharge. The results indicate that the composition of blended polymers has a strong effect on the specific capacitance. When the mass ratio of PF to gelatin is kept at 1：1, the largest surface area of 222 m2/g is obtained, and the specific capacitance reaches 161 F/g.
基金This Paper was presented before the Symposium on Polymers,Chengdu,P.R.China.Nov,14-18,1989
文摘The transition behaviour of the blends of isotactic polypropylene (i-PP) with ethylene-propylene terpolymer (EPDM) containing 42 wt% propylene was investigated by dynamic mechanical analysis technique (DMA). Owing to its high propylene content, EPDM is compatible with i-PP to some degree. The interaction between the two components was strengthened. As expected, for partially compatible system the glass transition temperature of i-PP in the blends shifted to lower temperature. It was found that there existed two transitions, αEPDM and βEPDM, for the EPDM used in this work. The former was considered to be the glass transition of the random chain segments of EPDM, while the latter the local motion of the long ethylene sequences in EPDM. The unusual transition behaviour of αEPDM in the blends was explained in terms of the greater thermal expansion of EPDM and the compatibility of the two components. On the other hand, the βEPDM changed with the composition of the blends in a regular manner.
基金supported by National Natural Science Foundation (No. 60602065)Innovation Funds of University of Science and Technology of China for Graduate Student (No.KD2006009)
文摘Positron annihilation lifetime spectroscopy （PALS） is a powerful technique for the study of free volume in polymers. The lifetime of ortho-positronium （o-Ps）, a bound state of an electron and a positron, can be used to assess the pore size, while the intensity can be used to characterize the number of pores. Based on the values of the long-lived o-Ps components in the lifetime spectra, the radii and fractional free volumes of sulfonated poly （2,6-dimethyl-1,4- phenyleneoxide） （SPPO） membranes with added LiCl and SPPO-PES （Polyethersulfone） blend were compared. Free volume radii in both kinds of membranes are discussed.
