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Showing papers on "Miscibility published in 2017"


Journal ArticleDOI
TL;DR: This work introduces a new strategy for improving the conductivity of solution-processed n-type organic thermoelectrics by adapting the polarity of fullerene derivatives to enhance the miscibility of the host/dopant system at a nanoscale level and the high electrical conductivity.
Abstract: In this contribution, for the first time, the polarity of fullerene derivatives is tailored to enhance the miscibility between the host and dopant molecules. A fullerene derivative with a hydrophilic triethylene glycol type side chain (PTEG-1) is used as the host and (4-(1,3-dimethyl-2,3-dihydro-1H-benzoimidazol-2-yl)phenyl)dimethylamine n-DMBI) as the dopant. Thereby, the doping efficiency can be greatly improved to around 18% (<1% for a nonpolar reference sample) with optimized electrical conductivity of 2.05 S cm-1 , which represents the best result for solution-processed fullerene derivatives. An in-depth microstructural study indicates that the PTEG-1 molecules readily form layered structures parallel to the substrate after solution processing. The fullerene cage plane is alternated by the triethylene glycol side chain plane; the n-DMBI dopants are mainly incorporated in the side chain plane without disturbing the π-π packing of PTEG-1. This new microstructure, which is rarely observed for codeposited thin films from solution, formed by PTEG-1 and n-DMBI molecules explains the increased miscibility of the host/dopant system at a nanoscale level and the high electrical conductivity. Finally, a power factor of 16.7 µW m-1 K-2 is achieved at 40% dopant concentration. This work introduces a new strategy for improving the conductivity of solution-processed n-type organic thermoelectrics.

128 citations


Journal ArticleDOI
Bingcheng Luo1, Xiaohui Wang1, Hongxian Wang1, Ziming Cai1, Longtu Li1 
TL;DR: In this paper, P(VDF-HFPHFP)/PMMA composite films were fabricated using a blending and hot-molding method and investigated using both experimental and theoretical methods.

82 citations


Journal ArticleDOI
TL;DR: In this paper, a series of poly(ethylene terephthalate-co-1,4-cyclohexanedimethanol-terephthalates (PETG-block-PTMO) copolymers were synthesized by means of a polycondensation process and characterized using 1H nuclear magnetic resonance (H NMR) and Fourier transform infrared spectroscopy (FTIR) to confirm the successful synthesis of the material.
Abstract: A series of poly(ethylene terephthalate-co-1,4-cyclohexanedimethanol terephthalate)-block-poly(tetramethylene oxide) (PETG-block-PTMO) copolymers were synthesized by means of a polycondensation process and characterized using 1H nuclear magnetic resonance (H NMR) and Fourier transform infrared spectroscopy (FTIR), that confirm the successful synthesis of the material. Differential scanning calorimetry (DSC), small – and wide-angle X-ray diffraction (SAXS and WAXS), and thermogravimetric analysis (TGA) were used in order to evaluate the influence of the block copolymers' composition and microstructure on the phase transition temperatures, thermal properties, as well as the thermooxidative and thermal stability of the PETG-block-PTMO copolymers, respectively. The mechanical properties were investigated by tensile testing and dynamic mechanical measurements (DMTA). We found that along with an increase in PTMO weight fraction, both number-average molecular weights and intrinsic visocisities increase. Moreover, an increase in the flexible segments content in PETG-block-PTMO resulted in shifting the values of glass transition temperatures toward lower ones, which was confirmed by DSC and DMTA analyses, thus affirming the miscibility of both phases. At the same time, along with an increase of PTMO flexible segments amount in the PETG-block-PTMO copolymers, the values of Young's modulus, tensile strength at yield and weight losses in lower temperatures range, i.e. 280–390 °C, decrease.

61 citations


Journal ArticleDOI
TL;DR: In this article, the effects of PCBM loading, solvents, and additive on the glass transition temperature of conjugated polymers and polymer-polymer blends were investigated using dynamic mechanical thermal analysis (DMTA).
Abstract: Glass transition temperature is a critical parameter for achieving favorable and thermally stable bulk heterojunction morphology as it determines the kinetics of molecular organization of polymeric semiconducting materials. This study presents a sensitive method of precisely determining the glass transition temperature (Tg) of conjugated polymers and polymer–PCBM blends using dynamic mechanical thermal analysis (DMTA). The method presented here is very versatile in which polymer or polymer–molecule films are reinforced using a woven glass fiber and utilizes only 5–10 mg of the material. This makes the method superior to differential scanning calorimetry (DSC) for determining the thermal properties of conjugated polymers. The effects of PCBM loading, solvents, and additive on the Tg of polymer–PCBM blends and on the miscibility of different phases are investigated using the novel DMTA method. For the P3HT:PC61BM system, two different thermal transitions were found corresponding to P3HT-rich and PCBM-rich p...

53 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of aromatic, π electron interactions on miscibility and on the structure and properties of polypropylene (PP)/lignin blends were used as a reference.
Abstract: Polymer/lignosulfonate blends were prepared from three polymers containing an aromatic moiety in their chain: polystyrene (PS), polycarbonate (PC), and a glycol modified poly(ethylene terephthalate) (PETG), in order to study the effect of aromatic, π electron interactions on miscibility and on the structure and properties of the blends. Polypropylene (PP)/lignin blends were used as a reference. The components were homogenized in an internal mixer and compression molded into plates of 1 mm thickness. Structure was characterized by scanning electron microscopy (SEM) and image analysis, while mechanical properties were characterized by tensile testing and acoustic emission measurements. Component interactions were estimated from solubility parameters, the composition dependence of glass transition temperature, and mechanical properties. The results indicated that π electron interactions result in better compatibility than the dispersion forces acting in PP blends. The average size of the dispersed lignin par...

46 citations


Journal ArticleDOI
TL;DR: In this article, the noninvasive and nondestructive Fourier transform infrared (FTIR) imaging and dynamic mechanical analysis (DMA) are developed in order to evaluate the microstructure-related properties of UHMWPE/Recycled-PA6 blends.

43 citations


Journal ArticleDOI
TL;DR: In this article, the authors studied the miscibility of two polymers: the acrylonitrile butadiene styrene (ABS) composed of a dispersed elastomeric (polybutadiene rubber) polymer embedded in a SAN thermoplastic matrix, and the polycarbonate (PC).
Abstract: In the challenging prospect of developing new materials by mixing different polymers to reach a synergetic performance, the present research focuses on the study of the miscibility of two polymers: The acrylonitrile butadiene styrene (ABS) composed of a dispersed elastomeric (polybutadiene rubber) polymer embedded in a SAN thermoplastic matrix, and the polycarbonate (PC). It shall be noted that obtaining miscible polymer blends is often a difficult task because of the large size of their molecular chains and the high interfacial tension between the polymer phases. Until now, the most numerous researches developed in this field involve polymer blends obtained by compatibilization techniques in order to improve the interfacial adhesion between initial polymers. The aim of this work is to study the miscibility between ABS and PC. First, two different methods were used to mix the polymers: the twin-screw extrusion and the dissolution in a common solvent tetrahydrofuran (THF). Then, physicochemical, microscopic observation and rheological characterization were performed on samples of mixtures obtained by both extrusion processing and dissolution method. The measurement of glassy transition temperature (Tg) by differential scanning calorimetry measurements (DSC) and dynamical mechanical thermal analysis (DMTA) have shown a partial miscibility between the two polymers. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44975.

41 citations


Journal ArticleDOI
TL;DR: In this paper, a molecular dynamics simulation technique was employed to predict miscibility and interaction of Active Pharmaceutical Ingredient (API) with polymer carriers in solid dispersion system based on Hansen solubility parameter and hydrogen bond formation, respectively.
Abstract: In this study, a molecular dynamics simulation technique was employed to predict miscibility and interaction of Active Pharmaceutical Ingredient (API) with polymer carriers in solid dispersion system based on Hansen solubility parameter and hydrogen bond formation, respectively. Several APIs with and without hydrogen bonding tendency were studied. The Hansen solubility parameters of APIs and polymers calculated by molecular dynamic simulation were similar to reported values in the literature. Our simulation results were able to determine the interactions between APIs and various polymers (ionic and nonionic) and also predict the hydrogen bond interaction energy and hydrogen bond lifetime. The simulation results were verified by preparing solid dispersions using hot melt extrusion. As predicted by our simulation, clear and colorless extrudates were obtained for ibuprofen/PVP-VA 64, ibuprofen/Eudragit EPO, and fenofibrate/PVP-VA 64, which confirmed the miscibility between APIs (ibuprofen, fenofibrate) and p...

40 citations


Journal ArticleDOI
TL;DR: In this paper, a mixture of poly(3-hydroxybutyrate) (PHB) and polycaprolactone (PCL) was obtained through solution casting and their miscibility and crystallinity were studied.

34 citations


Journal ArticleDOI
05 Oct 2017
TL;DR: The final properties of the multiphase polymeric composites are found to be related to the morphology obtained and inherent properties ofThe individual constituents.
Abstract: The incorporation of poly(lactic acid) (PLA) and poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) as a partial biobased polymer substitute for polypropylene (PP) was investigated. The ternary blends were prepared through melt compounding extrusion followed by injection molding techniques with a constant biopolymer ratio of 30 wt %. Further addition of pyrolyzed miscanthus-based carbon was carried out to establish a contrast between talc-filled PP. When the morphology of the biopolymer minor phase was analyzed theoretically using contact angle for interfacial tension and spreading coefficient values along with solubility parameter calculations and via scanning electron microscopy imaging, the core–shell architecture was found with the PHBV encasing the PLA phase. Mechanical testing of the materials showed that only the tensile properties were reduced for all samples, whereas the impact strength was increased above the neat PP. With inclusion of the biobased carbon filler into the blend system, the thermomec...

33 citations


Journal ArticleDOI
TL;DR: In this article, high-resolution scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) capabilities were used for microstructural characterization of transition metal (Co-Cu-Fe) high entropy alloys.

Journal ArticleDOI
TL;DR: In this paper, the acceptor loadings in optimized bulk-heterojunction (BHJ) solar cells were analyzed as a function of the polymer-fullerene miscibility.
Abstract: Organic photovoltaics is one of the most promising technologies for sustainable green energy supply. Because of their high electron affinity and superior electron-transporting ability, fullerene-based materials are deemed as very strong electron-accepting components in organic solar cells. However, the most widely used fullerene-based acceptors, such as phenyl-C61-butyric acid methyl ester, exhibit limited microstructural stability and unsatisfactory thermal stability owing to their insufficient compatibility with organic donors. Here, we in-depth investigate the carrier dynamics along with structural evolution and analyze the acceptor loadings in optimized bulk-heterojunction (BHJ) solar cells as a function of the polymer–fullerene miscibility. The polymer–fullerene miscibility has more influential effects than the crystallinity of single components on the optimized acceptor : donor ratio in polymer–fullerene solar cells. The findings demonstrated in this work suggest that the balance between the miscibility of BHJ composites and their optoelectronic properties has to be carefully considered for future development and optimization of OPV solar cells based on BHJ composites. Miscibility is proposed in addition to crystallinity as a further design criterion for long lived and efficient solar cells.

Journal ArticleDOI
TL;DR: Aqueous sodium hydroxide (NaOH) solution is proposed to modulate the miscibility of a representative natural-synthetic hybrid of gelatin (GT) and polycaprolactone (PCL) for electrospinning homogeneous composite nanofibers to solve the phase separation issue of the synthetic-natural hybrid GT/PCL.
Abstract: Electrospun natural-synthetic composite nanofibers, which possess favorable biological and mechanical properties, have gained widespread attention in tissue engineering. However, the development of biomimetic nanofibers of hybrids remains a huge challenge due to phase separation of the polymer blends. Here, aqueous sodium hydroxide (NaOH) solution is proposed to modulate the miscibility of a representative natural-synthetic hybrid of gelatin (GT) and polycaprolactone (PCL) for electrospinning homogeneous composite nanofibers. Alkali-doped GT/PCL solutions and nanofibers examined at macroscopic, microscopic, and internal molecular levels demonstrate appropriate miscibility of GT and PCL after introducing the alkali dopant. Particularly, homogeneous GT/PCL nanofibers with smooth surface and uniform diameter are obtained when aqueous NaOH solution with a concentration of 10 m is used. The fibers become more hydrophilic and possess improved mechanical properties both in dry and wet conditions. Moreover, biocompatibility experiments show that stem cells adhere to and proliferate better on the alkali-modified nanofibers than the untreated one. This study provides a facile and effective approach to solve the phase separation issue of the synthetic-natural hybrid GT/PCL and establishes a correlation of compositionally and morphologically homogeneous composite nanofibers with respect to cell responses.

Journal ArticleDOI
Yang Yu1, Lin Sang1, Zhiyong Wei1, Xuefei Leng1, Yang Li1 
21 Apr 2017-Polymer
TL;DR: In this paper, a model of crystal lattice structure of copolyesters was proposed to better understand the difference in cocrystallization miscibility effect of comonomers between isodimorphism and isomorphism.

Journal ArticleDOI
24 Mar 2017-Polymer
TL;DR: In this article, the authors explored the different methods currently available to obtain the partial solubility parameters of polymers in order to apply them for the prediction of miscibility in polymer/polymer blends.

Journal ArticleDOI
TL;DR: In this article, computer simulation and experiments were performed to investigate the miscibility of PLA/PEG blends with different PEG concentrations, and the calculated χ parameter and radial distribution function suggest that the PLA and PEG blends are likely miscible at low pEG concentrations (10-30-wt), but they become apparently immiscible at higher pEG content (>50-wt%).
Abstract: Computer simulation and experiments were performed to investigate the miscibility of PLA/PEG blends with different PEG concentrations. Flory-Huggins interaction (χ) parameter used to predict the miscibility for the blends was estimated by molecular dynamic simulation of fully atomistic model. The calculated χ parameter and radial distribution function suggest that the PLA and PEG blends are likely miscible at low PEG concentrations (10–30 wt%), but they become apparently immiscible at higher PEG content (>50 wt%). This result is consistent with density distribution of PLA and PEG beads calculated from dissipative particle dynamics simulation of coarse-grained model. To support the computational results, experiments based on differential scanning calorimetry (DSC) and rheometry were also performed. The DSC thermograms of 90:10, 80:20, and 70:30 (wt/wt) of PLA/PEG blends showed a single glass transition and PLA melting peak, indicating PLA/PEG is miscible over this composition. In rheometry, frequency (ω) dependence of storage moduli (G′) at low frequencies for 75:25 and 70:30 blends indicate that these samples are near the phase separation point.

Journal ArticleDOI
21 Dec 2017-Polymers
TL;DR: In this article, a mixture of 3-hydroxybutyrate (PHB), poly(e-caprolactone) and poly(lactic acid) was used to improve the low intrinsic toughness of PLA.
Abstract: Ternary blends with a constant poly(lactic acid) (PLA) content (60 wt %) and varying amounts of poly(3-hydroxybutyrate) (PHB) and poly(e-caprolactone) (PCL) were manufactured by one step melt blending process followed by injection moulding, with the main aim of improving the low intrinsic toughness of PLA. Mechanical properties were obtained from tensile and Charpy impact tests. The miscibility and morphology of the system was studied by thermal analysis and field emission scanning electron microscopy (FESEM). The obtained results showed a clear phase separation, thus indicating poor miscibility between these three biopolyesters, i.e., PLA, the continuous component with dispersed PHB and PCL domains in the form of different sphere size. Nevertheless, the high fragility of PLA was remarkably reduced, as detected by the Charpy impact test. In accordance with the decrease in brittleness, a remarkable increase in elongation at break is achieved, with increasing PCL load due to its flexibility; in addition, increasing PCL load provides thermal stability at high temperatures. Thus, tailored materials can be manufactured by melt blending PLA, PHB, and PCL in different percentages to offer a wide range of biodegradable polymer blends.

Journal ArticleDOI
TL;DR: In this article, an asymmetrical lower critical solution temperature (LCST) phase diagram was observed from dynamic temperature sweep experiments in which the system became immiscible after the solid-liquid phase transition (SLPS) temperatures in the PEO-rich blends.
Abstract: Blends of two semi-crystalline polymers, poly(vinylidene fluoride) (PVDF) and poly(ethylene oxide) (PEO), were prepared via solution mixing method over the whole composition range. The research focuses on the liquid–liquid phase separation (LLPS) and miscibility window in the PVDF/PEO blends by employing several techniques. Small-amplitude oscillatory shear measurements were carried out to detect LLPS and determine spinodal and binodal decomposition temperatures in its early stages. An asymmetrical lower critical solution temperature (LCST) phase diagram was observed from dynamic temperature sweep experiments in which the system became immiscible after the solid–liquid phase transition (SLPS) temperatures in the PEO-rich blends. In fact, a one-way partial miscibility of PEO in the PVDF-rich phase blends was observed. The rheologically determined phase diagram was also verified by means of optical microscopy and cloud point technique. The results revealed that the PVDF/PEO blends undergo a viscoelastic phase separation (VPS). This was attributed to the large viscoelastic asymmetry of the components in the blend. A compressible regular solution free energy model was employed to determine the spinodal temperatures theoretically. The comparison between the experimental results and the mathematical modeling indicated that the model is able to predict the phase behavior qualitatively.

Journal ArticleDOI
08 Nov 2017-Langmuir
TL;DR: The mechanism by which the core/shell structure is transformed into single-hole hollow microspheres is proposed to be primarily based on the evaporation through the shell and extraction by ethanol of the core solution and is described in detail.
Abstract: We describe the co-electrospraying of hollow microspheres from a polycaprolactone (PCL) shell solution and various core solutions including water, cyclohexane, polyethylene oxide (PEO) and polyethylene glycol (PEG), using different collectors. The morphologies of resultant microspheres were characterized by scanning electron microscopy (SEM), confocal microscopy and nano-XCT. The core/shell solution miscibility played an important role in the co-electrospraying process and the formation of microsphere structures. Spherical shaped particles were more likely to be produced from miscible combinations of core/shell solutions than those from immiscible ones. Hollow PCL microspheres with a single-hole in their surfaces were produced when an ethanol bath was used as the collector. The mechanism by which the core/shell structure is transformed into single-hole hollow microspheres is proposed to be primarily based on the evaporation through the shell and extraction by ethanol of the core solution and is described ...

Journal ArticleDOI
TL;DR: The fatty acid as switchable solvent could be applied for oily contaminant removal from oily solid wastes as it shows a negligible adsorption on solid surfaces.

Journal ArticleDOI
TL;DR: In this article, a melt-induced degradation process of PLA/PHB blends was implemented, termed the in-situ selfcompatibilization approach, to produce low-molecular-weight PHB during melt blending process.
Abstract: Biodegradable polymer blends of high-molecular-weight poly(3-hydroxybutyrate) (PHB) and poly(lactic acid) (PLA) are not miscible in general Yet, by decreasing the molecular weight of PHB, the low-molecular-weight PHB could have improved miscibility with the PLA In this study, a melt-induced degradation process of PLA/PHB blends was therefore implemented, termed the in-situ self-compatibilization approach, to produce low-molecular-weight PHB during melt blending process The solution blends of PLA and oligomer PHB (PLA/OPHB) were also prepared as a basis to understand the role of low-molecular-weight PHB to improve its miscibility with PLA in PLA/PHB blends Only one single glass transition temperature (Tg) was found for the resulting PLA/PHB blends at compositions of 95/05 to 80/20, proving that the miscibility was greatly improved by decreasing molecular weight of PHB Because the degraded PHB had a relatively lower Tg, it thus provided plasticization effect to the PLA and resulted in the decreased crystallization temperature Moreover, with increasing PHB content to 20% in the blend, the elongation at break increased significantly from 72% to 227%, more than 30-fold The extensive shear yielding and necking behavior were observed during tensile testing for the blend of 80/20 The localized plasticization within PLA/PHB matrix with the reduction of local yield stress and the well-dispersed PHB crystallites were the major contributing factors to trigger shear yielding phenomenon Moreover, initial modulus decreased only 20%, from 168 to 135 GPa A common problem of severely reduced stiffness from the added plasticizer encountered in the plasticized PLA blends was therefore not perceived here

Journal ArticleDOI
24 Feb 2017-Polymer
TL;DR: In this article, the phase inversion of the polymer solution was studied using the cloud-point method, light microscopy, and Langmuir isotherm, which was mainly attributed to an increase in polymer miscibility in the aqueous non-solvent bath with an increasing degree of sulfonation.

Journal ArticleDOI
TL;DR: The novel method presented resulted in the formation of biocomposite films whose physico-chemical properties can be tuned by silk fibroin conformational changes by applying different component mixing ratios.
Abstract: Miscibility is an important issue in biopolymer blends for analysis of the behavior of polymer pairs through the detection of phase separation and improvement of the mechanical and physical properties of the blend. This study presents the formulation of a stable and one-phase mixture of collagen and regenerated silk fibroin (RSF), with the highest miscibility ratio between these two macromolecules, through inducing electrostatic interactions, using salt ions. For this aim, a ternary phase diagram was experimentally built for the mixtures, based on observations of phase behavior of blend solutions with various ratios. The miscibility behavior of the blend solutions in the miscible zones of the phase diagram was confirmed quantitatively by viscosimetric measurements. Assessing the effects of biopolymer mixing ratio and salt ions, before and after dialysis of blend solutions, revealed the importance of ion-specific interactions in the formation of coacervate-based materials containing collagen and RSF blends that can be used in pharmaceutical, drug delivery, and biomedical applications. Moreover, the conformational change of silk fibroin from random coil to beta sheet, in solution and in the final solid films, was detected by circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR), respectively. Scanning electron microscopy (SEM) exhibited alterations of surface morphology for the biocomposite films with different ratios. Surface contact angle measurement illustrated different hydrophobic properties for the blended film surfaces. Differential scanning calorimetry (DSC) showed that the formation of the beta sheet structure of silk fibroin enhances the thermal stability of the final blend films. Therefore, the novel method presented in this study resulted in the formation of biocomposite films whose physico-chemical properties can be tuned by silk fibroin conformational changes by applying different component mixing ratios.

Journal ArticleDOI
TL;DR: In this article, the effects of blend ratio and molecular mass of PCL (PCL1 and PCL2) on morphology, miscibility, crystallinity, thermal properties, surface hydrophilicity and cell culture of the nanofibres were investigated.
Abstract: Ternary blends of poly(lactic acid) (PLA), polycaprolactone (PCL) and cellulose acetate butyrate (CAB) were fabricated into the form of electrospun nanofibres targeted for skin tissue scaffolds. The effects of blend ratio and molecular mass of PCL (PCL1 and PCL2) on morphology, miscibility, crystallinity, thermal properties, surface hydrophilicity and cell culture of the nanofibres were investigated. Blends with high PLA loading (80/10/10 PLA/PCL/CAB) gave fibres with a smooth surface, owing to the enhanced miscibility between the polymer chains from the presence of CAB, which acts as compatibilizer. In contrast, blends with high PCL loading were immiscible, which led to beads during the electrospinning process. The increased molecular mass of PCL2 produced smoother fibres than low-molecular-mass PCL1. The XRD patterns of blends of PLA/PCL1/CAB and PLA/PCL2/CAB were similar to one another, in which the high-crystallinity peaks of PCL seen for 20/70/10 blends were very small for 50/40/10 blends and much less prevalent for 80/10/10 blends. Better fibre formation (80/10/10>50/40/10>20/70/10) with less crystallinity occurs in well-formed fibres. Selected blends of PLA/PCL/CAB promoted growth of NIH/3T3 fibroblast cells, demonstrating that our novel biocompatible ternary blend nanofibrous scaffolds have potential in skin tissue repair applications. In addition, this work helps in the design and understanding of the factors that control the properties of nanofibrous PLA/PCL/CAB scaffolds.

Journal ArticleDOI
TL;DR: It is demonstrated that both temperature and surface pressure affected the miscibility between the milk-SM and cholesterol.

Journal ArticleDOI
TL;DR: In this article, a comprehensive study on the electrospinning of the blends [pitch and polyacrylonitrile (PAN)] was explored, where Fourier transfer infrared spectroscopy was used to show interaction and potential reaction between pitch and PAN molecules.
Abstract: Continuous carbon nanofibers had been widely studied based on different processing methods and precursors. Especially, electrospinning was introduced as a versatile method for fabricating ultrathin fibers. However, as the limitation of precursor, pitch had not been well studied due to its viscosity and miscibility problem. A comprehensive study on the electrospinning of the blends [pitch and polyacrylonitrile (PAN)] was explored. Thermodynamic miscibility was studied by using differential scanning calorimeter. Fourier transfer infrared spectroscopy was used to show interaction and potential reaction between pitch and PAN molecules. Finally, smooth, continuous, and cylindrical carbon nanofibers were successfully fabricated by electrospinning technique. Based on Raman analysis result, the addition of pitch enhanced the carbon crystallite which improved the overall electrical conductivity and modulus of nanofibers. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45388.

Journal ArticleDOI
TL;DR: A persistent challenge in membrane biophysics has been to quantitatively predict how membrane physical properties change upon addition of new amphiphiles, and here it is found that when GUVs of canonical ternary mixtures are formed in aqueous solutions of short-chain n-alcohols (n ≤ 10), Tmix increases relative to GUVs in water.

Journal ArticleDOI
TL;DR: In this article, the intermolecular interactions and miscibility behavior of two polyimide blend systems, Extem/Matrimid and extem/U-Varnish, in compositions of 100/0, 80/20, 50/50, 20/80, 0/100 have been evaluated by different analytical techniques such as optical microscopy, Differential scanning calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD) and rheological measurements.
Abstract: The intermolecular interactions and miscibility behavior of two polyimide blend systems, Extem/Matrimid and Extem/U-Varnish, in compositions of 100/0, 80/20, 50/50, 20/80, 0/100 have been evaluated. The polymer blend systems have been characterized by different analytical techniques such as optical microscopy, Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD) and rheological measurements. DSC results for the Extem/U-Varnish system showed the existence of a single glass transition temperature (Tg) in each composition, suggesting the miscibility of the blends, whereas DSC analysis of Extem/Matrimid system indicated immiscibility but compatibility between two polymers. In order to study the specific interactions between Extem and U-Varnish polymers, the Tgs of the polymer blends were estimated by theoretical equations and compared with experimental data. The empirical Tg values formed a concave curve as a function of composition and exhibited a positive deviation from the linearity, indicating the presence of specific interactions between Extem and U-Varnish polymer chains; this was confirmed by FTIR spectra. Interactions between studied polymer systems and four aprotic solvents including N -methyl-2-pyrrolidone (NMP), Dimethylacetamide (DMAc), Dimethylformamide (DMF) and Dimethyl sulfoxide (DMSO) were assessed on the basis of the difference between their solubility parameters. Among the selected solvents, DMAc showed the highest affinity with both blend systems. XRD patterns and rheological behavior of Extem/U-Varnish system revealed that the crystalline nature and viscosity of the blend polymers decreases as the ratio of Extem/U-Varnish increases. As an overall conclusion, Extem and U-Varnish were found to constitute a miscible pair at a molecular level over the entire composition range whereas Extem and Matrimid could not form a miscible blend.

Journal ArticleDOI
Chen Nan1, Yao Xuerong1, Zheng Cui1, Yujing Tang1, Minqiao Ren1, Ren Yi1, Meifang Guo1, Shijun Zhang1, Li-Zhi Liu1 
25 Aug 2017-Polymer
TL;DR: In this paper, the miscibility, crystalline structure and morphology, as well as properties of polyamide 6 (PA6)/polyvinylidene fluoride (PVDF) blends (with up to 50% of PVDF) were studied.

Journal ArticleDOI
TL;DR: In this paper, multicomponent metal-oxide nanoparticles consisting of combinations of Co, Ni, and Cu were synthesized by using scanning probe block copolymer lithography and characterized using correlated electron microscopy.
Abstract: Multicomponent nanoparticles can be synthesized with either homogeneous or phase-segregated architectures depending on the synthesis conditions and elements incorporated To understand the parameters that determine their structural fate, multicomponent metal-oxide nanoparticles consisting of combinations of Co, Ni, and Cu were synthesized by using scanning probe block copolymer lithography and characterized using correlated electron microscopy These studies revealed that the miscibility, ratio of the metallic components, and the synthesis temperature determine the crystal structure and architecture of the nanoparticles A Co-Ni-O system forms a rock salt structure largely owing to the miscibility of CoO and NiO, while Cu-Ni-O, which has large miscibility gaps, forms either homogeneous oxides, heterojunctions, or alloys depending on the annealing temperature and composition Moreover, a higher-ordered structure, Co-Ni-Cu-O, was found to follow the behavior of lower ordered systems