Showing papers on "Polymer blend published in 2017"
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TL;DR: In this article, a materials design concept for achieving large-area, solution-coated all-polymer bulk heterojunction solar cells with stable phase separation morphology between the donor and acceptor is presented.
Abstract: The challenge of continuous printing in high-efficiency large-area organic solar cells is a key limiting factor for their widespread adoption. A materials design concept for achieving large-area, solution-coated all-polymer bulk heterojunction solar cells with stable phase separation morphology between the donor and acceptor is presented. The key concept lies in inhibiting strong crystallization of donor and acceptor polymers, thus forming intermixed, low crystallinity, and mostly amorphous blends. Based on experiments using donors and acceptors with different degree of crystallinity, the results show that microphase separated donor and acceptor domain sizes are inversely proportional to the crystallinity of the conjugated polymers. This methodology of using low crystallinity donors and acceptors has the added benefit of forming a consistent and robust morphology that is insensitive to different processing conditions, allowing one to easily scale up the printing process from a small-scale solution shearing coater to a large-scale continuous roll-to-roll (R2R) printer. Large-area all-polymer solar cells are continuously roll-to-roll slot die printed with power conversion efficiencies of 5%, with combined cell area up to 10 cm2. This is among the highest efficiencies realized with R2R-coated active layer organic materials on flexible substrate.
215 citations
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TL;DR: In this paper, a thermodynamic method was proposed to precisely control multi-walled carbon nanotubes (MWCNTs) at the interface of a co-continuous PS/PMMA blend to design conductive polymer composites with ultralow percolation threshold.
172 citations
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TL;DR: In these eco-friendly structured bio-nanocomposites, the adhesion properties and the large number of functional groups that are present in the CNC's surface and the macromolecular chains of the PVA/CMC blend are exploited to improve the interfacial interactions between the C NC and the blend.
160 citations
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TL;DR: In this paper, Fourier transform infrared (FT-IR) and Ultraviolet/Visible (UV/Vis.) analyses were used to retrace the structural and optical changes with increasing Au content.
Abstract: Casting technique was used for preparation of polyethylene oxide (PEO)/polyvinyl pyrrolidone (PVP) (70/30 wt.%) films filled with different concentrations of gold nanoparticles (Au NPs). X-ray diffraction (XRD) pattern proved the semi-crystalline nature of the pristine and filled polymer blend. Fourier transform infrared (FT-IR) and Ultraviolet/Visible (UV/Vis.) analyses were used to retrace the structural and optical changes with increasing Au content. UV/Vis. analysis spectroscopy was utilized to calculate the optical properties such as optical energy gap E g , refractive index n and Urbach energy E u for blend/Au nanocomposite films. Scanning electron micrograph (SEM) suggested the dependence of morphological structure on filling level and the surface morphology changed from rough to smooth. Transmission electron microscope (TEM) micrographs showed that the size of Au NPs was increased with continuous filling in PEO/PVP. Thermogravimetric analysis (TGA) was performed to investigate the thermal stability for nanocomposite films.
157 citations
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TL;DR: In this article, the authors report the status of the research on degradation of polymer blends focusing on thermal, thermomechanical and photo-oxidative degradation, and present a review of the existing literature.
155 citations
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TL;DR: In this article, a double percolation structure for conductive polymer composites was constructed at PS/PP weight ratio of 60w/40w and the fourth component, styrene-ethylene/butylene-styrene (SEBS) triblock copolymer, was introduced as the compatibilizer to improve the mechanical properties.
114 citations
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TL;DR: In this paper, a composite material based on polymer blends of polyvinyl alcohol (PVA) and pyrrolidone (PVP) with small optical band gap was studied.
113 citations
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TL;DR: In this article, an experimental method has been proposed to estimate the optical bandgap and determine the types of electronic transitions, where solid polymer blend electrolyte films based on PVA:PEO have been prepared by the well known solution cast technique.
Abstract: In this work an innovative experimental method has been proposed to estimate the optical bandgap and determine the types of electronic transitions. Solid polymer blend electrolyte films based on PVA:PEO have been prepared by the well known solution cast technique. It was observed that the absorption increased with increasing aluminum salt concentration and shifted to higher wavelengths. Shifting of absorption edge to lower photon energy indicates a good reactivity between the polymer blends and the aluminum salt which in turn the energy band gap decrement is expected. An increase in refractive index for the doped samples has been observed. The miscibility between the aluminum salt and the polymer blends can be well understood from the linear relationship between the refractive index and the volume fraction of the added salt. The increase of extinction coefficient at high wavelengths was observed. The optical band gap measured from the plots of (αhυ)^x versus photon energy (hυ) was compared to that determined from the optical dielectric loss. From the results of the present work it is understood that in order to avoid the plotting of many figures based on Tauc model, optical dielectric loss must be studied. Further research works are required to satisfy that the optical dielectric loss can be used to estimate the band gap and identify the types of electronic transition. The Urbach energy was found to increase with increasing aluminum salt concentration.
107 citations
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TL;DR: A novel approach, termed as the interfacial nanoparticle compatibilization (IPC) mechanism, to overcome the challenges by packing nanoparticles thermodynamically at the interface through melt reactive blending of immiscible binary polymer blends.
Abstract: The exclusive location of compatibilizers at the interface of immiscible binary polymer blends to bridge the neighboring phases is the most important issue for fabricating desirable materials with synergistic properties. However, the positional stability of the compatibilizers at the interface remains a challenge in both scientific and technical points of view due to the intrinsic flexibility of compatibilizer molecules against aggressive processing conditions. Herein, taking the typical immiscible poly vinylidene fluoride (PVDF)/polylactic acid (PLLA) blend as an example, we demonstrate a novel approach, termed as the interfacial nanoparticle compatibilization (IPC) mechanism, to overcome the challenges by packing nanoparticles thermodynamically at the interface through melt reactive blending. Specifically, we have first synthesized nanosilica with both reactive epoxide groups and long poly(methyl methacrylate) (PMMA) tails, called reactive PMMA-graft-SiO2 (Epoxy-MSiO2), and then incorporated the Epoxy-M...
102 citations
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TL;DR: In this paper, the authors showed that the highest conducting plasticized electrolyte possesses the lowest glass transition temperature (T g) of −275 °C using differential scanning calorimetry (DSC).
Abstract: Potato starch (PS)-methyl cellulose (MC) blend solid biopolymer electrolytes infused with ammonium nitrate (NH4NO3) and glycerol as plasticizer are made via the solution cast technique Fourier transform infrared (FTIR) spectroscopy indicates that NH4NO3 has interacted with the polymer blend host The addition of 40 wt% glycerol in the highest conducting plasticizer free electrolyte has improved the conductivity to the order of ∼10−3 S cm−1 The thermal stability of the electrolytes is identified by thermogravimetric analysis (TGA) Result from X-ray diffraction (XRD) analysis shows that the electrolyte with maximum conductivity value has the lowest degree of crystallinity Differential scanning calorimetry (DSC) analysis reveals that the highest conducting plasticized electrolyte possesses the lowest glass transition temperature (T
g) of −275 °C Conductivity trend is further verified by dielectric analysis Transference numbers of ion (t
ion) and electron (t
e) for the highest conducting electrolyte are identified to be 098 and 002, respectively, confirming that ions are the dominant charge carriers Linear sweep voltammetry (LSV) evaluates that the potential window for the electrolyte is 188 V The internal resistance of the electrochemical double-layer capacitor (EDLC) is between 29 and 64 Ω From the charged-discharged measurement, the value of C
s is 31 F g−1 The EDLC is stable over 1000 cycles
101 citations
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TL;DR: In this article, the effect of multwalled carbon nanotubes (MWCNTs) on the rheology, morphology and broadband dielectric properties of polypropylene:polystyrene (PP:PS) blends was investigated.
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TL;DR: In this article, the authors created polylactic acid (PLA) and polystyrene (PS) cocontinuous blends filled with thermally reduced graphene oxide (r-GO) localized at the interface and demonstrated that the 3D r-GO network significantly increases the conductivity and the storage modulus of the melt blends.
Abstract: Interfacial localization of graphene in cocontinuous polymer blends is shown to be effective in stabilizing the cocontinuous morphology and increasing conductivity with a low electrical percolation threshold. We created polylactic acid (PLA) and polystyrene (PS) cocontinuous blends filled with thermally reduced graphene oxide (r-GO) localized at the interface. The resulting conductive composites show dramatically improved conductivity at low filler loadings and an ultralow percolation threshold of 0.028 vol. %. We systematically studied the changes of conductivity and rheology of the PLA-PS composites during annealing. We found that r-GO transfers from the PLA phase to the interface during melt compounding and annealing and forms a spanning 3D network, which effectively suppresses the coarsening of the cocontinuous structure. Our study demonstrated that the 3D r-GO network significantly increases the conductivity and the storage modulus of the melt blends. Finally, we constructed a simple model, which qua...
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TL;DR: In this paper, the linear viscoelastic properties of nanosilica-compatibilized PVDF/PLLA (poly(vinylidene fluoride)/poly(l-lactide)) blends are investigated using small amplitude oscillatory shear (SAOS).
Abstract: Exclusive localization of nanofillers at the interface of immiscible polymer blend has been confirmed to be effective in improving compatibility and facilitating the formation of nanofiller-network with very low percolation threshold, while the rheology of such nanofiller compatibilized blends has seldom been investigated. Herein, we present a systematic rheological study on nanosilica-compatibilized PVDF/PLLA (poly(vinylidene fluoride)/poly(l-lactide)) blends. The linear viscoelastic properties of the systems are evaluated using small amplitude oscillatory shear (SAOS). It is found that the interfacial jammed Janus grafted silica (JGS) located at the interface increases dynamic moduli at low frequency even with very low filler loadings. The nonterminal effects become more pronounced with increasing JGS loadings. Weighted relaxation spectra inferred from SAOS reveals that the shape relaxation of PVDF-droplets is strongly influenced by addition of JGS. The solid-like behavior of JGS-filled blends has been ...
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TL;DR: Melt-processing of complementary semiconducting polymer blends provides an average charge carrier mobility of 0.4 cm2 V-1 s-1 and current on/off ratios higher than 105, a record performance for melt-processed organic field-effect transistors.
Abstract: Melt-processing of complementary semiconducting polymer blends provides an average charge carrier mobility of 0.4 cm2 V-1 s-1 and current on/off ratios higher than 105 , a record performance for melt-processed organic field-effect transistors.
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TL;DR: In this paper, the effect of phase morphology on shape memory behavior was studied and a small number of MWCNTs were selectively incorporated into TPU phase of TPU50/PLA50 and TPU60/PLA40 blends to realize electro-active shape memory effect.
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TL;DR: In this paper, the solution casting technique was used to prepared polyethylene oxide (PEO)/polyvinyl pyrrolidone (PVP) polymer blend/0.72 (wt. %) gold nanoparticles (Au NPs).
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TL;DR: The results revealed that the developed bionanocomposites showed improved mechanical properties and decrease in oxygen permeability rate, and the developed bio-based composite incorporated with an optimal composition of nanocrystalline cellulose exhibits properties as compared to the polymer blend.
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TL;DR: In this paper, the effects of poly ethylene glycol (PEG) and TiO2 nanoparticles incorporation with poly (ether-block-amide) (PEBAX-1074) on CO2 and CH4 permeability values and ideal CO2/CH4 selectivity through the synthesized membranes were investigated.
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TL;DR: In this article, a molecular dynamics simulation is employed to investigate the effects of nano-SiO2 particles on the properties of polyvinyl alcohol (PVA)/poly(vinyl pyrrolidone) (PVP) blends.
Abstract: A molecular dynamics simulation is employed to investigate the effects of nano-SiO2 particles on the properties of polyvinyl alcohol (PVA)/poly(vinyl pyrrolidone) (PVP) blends and demonstrate the interaction mechanism of nano-SiO2 particles in blend systems. Six blend systems with different concentrations of SiO2 particles (0–12.8%) and two interfacial interaction models of polymers on the SiO2 surface were designed and analyzed in terms of density distribution, mechanical properties, fractional free volume, and X-ray diffraction patterns. The incorporation of nano-SiO2 particles into the PVA/PVP blend systems increased their mechanical properties, densities, and semicrystalline character. Density distribution analysis indicated PVA molecular chains are more easily adsorbed on the SiO2 surface than PVP molecular chains. Finally, an analysis of binding energies and pair correlation functions of interfacial interaction models revealed the interaction mechanism of nano-SiO2 particles in PVA/PVP systems. Hydrogen bond interactions between polar functional groups in polymer molecular chains and the hydroxyl groups of the SiO2 surface are involved in adsorption of the polymers on the SiO2 surface and explain why nano-SiO2 particles can significantly influence the properties of PVA/PVP systems.
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TL;DR: It is demonstrated that this 2D crystallization-driven self-assembly approach can be extended to heteroepitaxial growth by the use of different crystallizable polymers with compatible crystal structures, which allows the formation of well-defined "patchy" rectangular platelets and platelet block comicelles with different core chemistries.
Abstract: Rectangular platelets formed by the self-assembly of block copolymers in selective solvents are of interest for a range of applications. Recently, we showed that the seeded growth of crystallizable blends of a block copolymer and homopolymer yields well-defined, low area dispersity examples of these two-dimensional (2D) structures. The key feature was the use of the same crystallizable polymer segment in the seed and blend components to enable an efficient homoepitaxial growth process. Herein we demonstrate that this 2D crystallization-driven self-assembly approach can be extended to heteroepitaxial growth by the use of different crystallizable polymers with compatible crystal structures. This allows the formation of well-defined “patchy” rectangular platelets and platelet block comicelles with different core chemistries. The use of scanning transmission electron microscopy–energy-dispersive X-ray spectroscopy provided key information on the spatial location of the components in the resulting assemblies a...
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TL;DR: A review of research activities on 1-D polymer nanostructures fabricated by anodic aluminum oxide (AAO) templates is presented in this paper, where the preparation methods of polymers by AAO templates including polymer melt infiltration, polymer solution infiltration, and chemical synthesis are introduced.
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TL;DR: In this article, a phase-separated poly(ether sulfone) (PES)/sufonated poly (ether ether ketone) blend membranes with tunable pore size are prepared via the phase inversion method.
Abstract: Porous membranes with critically hydrophobic/hydrophilic phase-separated-like structures for use in vanadium flow battery application are first realized by solvent-induced reassembly of a polymer blend system. Porous poly(ether sulfone) (PES)/sufonated poly(ether ether ketone) (SPEEK) blend membranes with tunable pore size are prepared via the phase inversion method. After solidification, isopropanol (IPA) is introduced to induce the reassembly of sulfonated groups and further form ion-transport channels by using the interaction between IPA and functional groups in SPEEK. As a result, a highly phase separated membrane structure is created, composed of a highly stable hydrophobic porous PES matrix and hydrophilic interconnected small pores. The charged pore walls are highly beneficial to improving proton conductivity, while pores are simultaneously shrunk during the IPA treatment. Therefore, the resultant membranes show an excellent battery performance with a coulombic efficiency exceeding 99%, along with an energy efficiency over 91%, which is among the highest values ever reported. This article supplies an ease-to-operate and efficient method to create membranes with controlled ion-transport channels.
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TL;DR: The polymer particles with different surface textures demonstrated good cell viability and biocompatibility, indicating the promising role of the particles in the fields of drug or gene delivery for tumor therapy, vaccines, biodiagnostics, and bioimaging.
Abstract: Generally, size, uniformity, shape, and surface chemistry of biodegradable polymer particles will significantly affect the drug-release behavior in vitro and in vivo. In this study, uniform poly(d,l-lactic-co-glycolide) (PLGA) and PLGA-b-poly(ethylene glycol) (PLGA-b-PEG) microparticles with tunable surface textures were generated by combining the interfacial instabilities of emulsion droplet and polymer-blending strategy. Monodisperse emulsion droplets containing polymers were generated through the microfluidic flow-focusing technique. The removal of organic solvent from the droplets triggered the interfacial instabilities (spontaneous increase in interfacial area), leading to the formation of uniform polymer particles with textured surfaces. With the introduction of homopolymer PLGA to PLGA-b-PEG, the hydrophobicity of the polymer system was tailored, and a qualitatively different interfacial behavior of the emulsion droplets during solvent removal was observed. Uniform polymer particles with tunable su...
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TL;DR: In this article, structural, thermal, and mechanical properties of pure blend and nanocomposites based on polyurethane (PU) and polyvinyl chloride (PVC) doped with low different content of single walled-carbon nanotubes (SWCNTs) were studied.
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TL;DR: In this paper, the maleic anhydride (MAH) and styrene (St) dual monomers grafted PP, PP-g-(MAH-co-St) is prepared as a multi-phase compatibilizer, which exhibits highly effective compatibility on the PP/PA6/SEBS (70/15/15) ternary blends.
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TL;DR: In vitro study indicated electrospun collagen/PCL/NBG nanofibrous conduit promoted Human Endometrial Stem cells (hEnSCs) adhesion and proliferation and contact angle and tensile tests were indicated that electrospin webs showed good hydrophilicity and toughness properties.
Abstract: Among various methods, nerve tissue engineering (NTE) is one of the applicable methods to reconstruct damaged nerve tissues. Electrospinning technique and biomaterials are often considered to fabricate fibrous tissue engineered conduits which have great similarity to the extracellular matrix on fiber structure. Polymer blending is one of the most effective methods for the production of new materials with outstanding features. In this study, conduit structures as main part of the peripheral nerve regeneration based on polymer blend nanocomposites poly(e-caprolactone)/collagen/nanobioglass (PCL/collagen/NBG) were manufactured by electrospinning technique. Various properties of electrospun mats were investigated by using contact angle, tensile, degradation time, porosity, scanning electron microscopy (SEM), Fourier-transform infrared (FTIR), and wide-angle X-ray scattering (WAXS). The SEM analysis was shown that size range and average pore size of polymer blend nanocomposite nanofibers were about 250-400 nm and 0.7 µm, respectively, with an optimum porosity of 62.5%. The XRD result was shown that synthesized nanoparticles of NBG had amorphous structures. Also, FTIR analysis indicated that good interaction between polymer-polymer macromolecules and polymer particles. The contact angle and tensile tests were indicated that electrospun webs showed good hydrophilicity and toughness properties. According to SEM, MTT assay and DAPI staining technique, the ability to support cell attachment and viability of samples were characterized. In vitro study indicated electrospun collagen/PCL/NBG nanofibrous conduit promoted Human Endometrial Stem cells (hEnSCs) adhesion and proliferation. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1960-1972, 2017.
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TL;DR: In this article, the influence of viscosity ratio on the morphology, mechanical, thermal and rheological properties of PLA/PBAT (70/30 w/w) blends was investigated.
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TL;DR: In this paper, the dielectric dispersion and relaxation processes in these polymer nanocomposite (PNC) films (i.e., (PVA-PEO)- x wt% ZnO; x = 0, 1, 3 or 5) have been investigated over the frequency range from 20-Hz to 1-MHz by employing the DRS.
Abstract: The organic-inorganic nanocomposite materials consisted of poly(vinyl alcohol) (PVA) and poly(ethylene oxide) (PEO) blend matrix (50/50 wt%) dispersed with zinc oxide (ZnO) nanoparticles have been prepared by the aqueous solution-cast method. The dielectric dispersion and relaxation processes in these polymer nanocomposite (PNC) films (i.e., (PVA-PEO)- x wt% ZnO; x = 0, 1, 3 or 5) have been investigated over the frequency range from 20 Hz to 1 MHz by employing the dielectric relaxation spectroscopy (DRS). Influence of ZnO contents on the complex dielectric permittivity, electrical conductivity, electric modulus and impedance properties of these PNC materials has been explored. The dielectric permittivity and the relaxation time values corresponding to polymers cooperative chain segmental motion significantly change with the variation of ZnO contents in the PVA-PEO blend matrix at ambient temperature. The temperature dependent relaxation times and dc conductivity values of (PVA-PEO)-3 wt% ZnO film have been investigated which obey the Arrhenius behaviour. The dielectric permittivity of the film as a function of temperature exhibits linear behaviour at radio frequencies and non-linear variation at lower audio frequencies. X-ray diffraction measurements confirm a huge decrease in crystalline phase of the polymer blend matrix on the addition of 1 wt% ZnO nanoparticles. These PNC materials have low values of dielectric permittivity and electrical conductivity which confirm their suitability as novel flexible-type polymer nanodielectric for the insulation in microelectronic devices, whereas the fast chain segmental dynamics and high amorphous phase reveal these materials as a potential candidate for the preparation of nanocomposite solid polymer electrolytes.
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TL;DR: In this article, the same authors examined the same acid-base blend PBI-based materials to obtain a deeper understanding of the relationship between the chemical structure and the membrane properties, particularly in the presence of phosphoric acid.
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TL;DR: In this paper, a flat-sheet ultra-filtration (UF) membrane was constructed from acid/base polymer complexes via non-solvent induced phase inversion and the potential for ultra-filtering was explored.