Showing papers on "Polymer blend published in 2016"
TL;DR: This work demonstrates a rational design for fine-tuned crystallinity of polymer acceptors, and reveals the high potential of all-PSCs through structure and morphology engineering of semicrystalline polymer:polymer blends.
Abstract: Growing interests have been devoted to the design of polymer acceptors as potential replacement for fullerene derivatives for high-performance all polymer solar cells (all-PSCs). One key factor that is limiting the efficiency of all-PSCs is the low fill factor (FF) (normally <0.65), which is strongly correlated with the mobility and film morphology of polymer:polymer blends. In this work, we find a facile method to modulate the crystallinity of the well-known naphthalene diimide (NDI) based polymer N2200, by replacing a certain amount of bithiophene (2T) units in the N2200 backbone by single thiophene (T) units and synthesizing a series of random polymers PNDI-Tx, where x is the percentage of the single T. The acceptor PNDI-T10 is properly miscible with the low band gap donor polymer PTB7-Th, and the nanostructured blend promotes efficient exciton dissociation and charge transport. Solvent annealing (SA) enables higher hole and electron mobilities, and further suppresses the bimolecular recombination. As expected, the PTB7-Th:PNDI-T10 solar cells attain a high PCE of 7.6%, which is a 2-fold increase compared to that of PTB7-Th:N2200 solar cells. The FF of 0.71 reaches the highest value among all-PSCs to date. Our work demonstrates a rational design for fine-tuned crystallinity of polymer acceptors, and reveals the high potential of all-PSCs through structure and morphology engineering of semicrystalline polymer:polymer blends.
385 citations
TL;DR: In this paper, the authors provide an overview of recent progress towards the performance enhancement of polymer/polymer blend solar cells, and discuss the future outlook and challenges regarding PCEs beyond 10%.
Abstract: Polymer/polymer blend solar cells based on a blend of two types of conjugated polymers acting as an electron donor (hole transport) and acceptor (electron transport) have recently attracted considerable attention, because they have numerous potential advantages over conventional polymer/fullerene blend solar cells. The highest power conversion efficiency (PCE) was slightly above 2% five years ago, whereas PCEs of beyond 8% are the state-of-the-art today, and the efficiency gap between polymer/polymer and polymer/fullerene systems has closed very rapidly. In this review, we provide an overview of recent progress towards the performance enhancement of polymer/polymer blend solar cells. In addition, we discuss the future outlook and challenges regarding PCEs beyond 10%.
241 citations
TL;DR: In this article, the authors used time-domain thermoreflectance (TDTR) and the generation and detection of longitudinal and surface acoustic waves, to study the thermal conductivity, heat capacity, and elastic properties of thin films of poly(vinyl alcohol) (PVA), poly(acrylic acid)(PAA), polyacrylamide (PAM), polyvinylpyrrolidone), methyl cellulose (MC), poly4-styrenesulfonic acid) (PSS), polyN-acryloylpiperidine
Abstract: We use time-domain thermoreflectance (TDTR), and the generation and detection of longitudinal and surface acoustic waves, to study the thermal conductivity, heat capacity, and elastic properties of thin films of poly(vinyl alcohol) (PVA), poly(acrylic acid) (PAA), polyacrylamide (PAM), poly(vinylpyrrolidone) (PVP), methyl cellulose (MC), poly(4-styrenesulfonic acid) (PSS), poly(N-acryloylpiperidine) (PAP), poly(methyl methacrylate) (PMMA), and a polymer blend of PVA/PAA. The thermal conductivity of six water-soluble polymers in the dry state varies by a factor of ≈2, from 0.21 to 0.38 W m–1 K–1, where the largest values appear among polymers with a high concentration of hydrogen bonding (PAA, PAM, PSS). The longitudinal elastic constants range from 7.4 to 24.5 GPa and scale linearly with the shear elastic constants, suggesting a narrow distribution of Possion’s ratio 0.35 < ν < 0.40. The thermal conductivity increases with the average sound velocity, as expected based on the model of the minimum thermal c...
197 citations
TL;DR: Results indicated that interplay of the miscibility between excipients in the blends, the solubility of the materials in the dissolution media and the degree of fusion between the printed strips during FDM process can be used to manipulate the drug release rate of the dispersions.
191 citations
TL;DR: In this article, an optimized composition of 1.6% poly(3-hexylthiophene) (P3HT) blended with polystyrene (PS) as a semiconductor layer were fabricated.
Abstract: Ammonia (NH 3 ) gas sensors based on organic field-effect transistor (OFET) using poly(3-hexylthiophene) (P3HT) blended with polystyrene (PS) as a semiconductor layer were fabricated. An optimized composition of 1.6 wt% P3HT in PS matrix exhibited the best performance to various concentrations of NH 3 , which is comparable to that of pure P3HT (8 wt%). The results showed the percentage responses of saturation current were 52% and 16% under 50 ppm and 5 ppm NH 3 , respectively. Also, it showed that there was a remarkable shift in the field-effect mobility after exposed to NH 3 gas. By analyzing the morphologies of blend films and the electrical characteristics of OFET sensors, it was found that the film of P3HT blended with PS has more interface to interact with NH 3 , resulting in more efficient detection to NH 3 even in the range of low concentration. Besides, the PS matrix would prevent the gas from diffusing into the semiconductor/dielectric interface directly, which was beneficial to the selectivity of P3HT/PS blend OFET sensor. Moreover, the sensing property was related to the solvents and molecular weight of PS. In addition, the environmental stability of OFET sensors was measured after storing the sensors under ambient atmosphere for 40 days, and the device with the blend semiconducting layer exhibited the superior stability.
159 citations
TL;DR: A ternary organic semiconducting blend composed of a small-molecule, a conjugated polymer, and a molecular p-dopant is developed and used in solution-processed organic transistors with hole mobility exceeding 13 cm(2) V (-1) s(-1) (see the Figure).
Abstract: A ternary organic semiconducting blend composed of a small-molecule, a conjugated polymer, and a molecular p-dopant is developed and used in solution-processed organic transistors with hole mobility exceeding 13 cm(2) V(-1) s(-1) (see the Figure). It is shown that key to this development is the incorporation of the p-dopant and the formation of a vertically phase-separated film microstructure.
158 citations
TL;DR: In this article, the glass transition temperature (T g ) of polyhedral oligomeric silsesquioxanes (POSSs) is investigated and the dependence of T g on the composition of POSS nanomaterials can be discussed and considered in terms similar to those used for polymer blends and copolymers.
144 citations
TL;DR: A critical overview of publications on applications of supercritical fluids in polymer formation, modification and processing is presented in this article, focusing on publications that appeared in 2014 only with the intent of providing an in-depth look at the activity in the most recent year to gain insights on the more recent trends and opportunities.
Abstract: A critical overview of publications on applications of supercritical fluids in polymer formation, modification and processing is presented. The review is focused on publications that appeared in 2014 only with the intent of providing an in-depth look at the activity in the most recent year to gain insights on the more recent trends and opportunities. The articles have been grouped under ten different application areas which include (1) polymer solutions and phase behavior, (2) polymerizations, (3) particle formation/micronization/drug delivery systems, (4) films, (5) fibers, (6) membranes, (7) nanocomposites, (8) porous materials – foams/scaffolds, (9) organogels, and (10) lignocellulosic polymers. In each category, articles are discussed under specific polymer or polymer type to better highlight those polymers that are receiving the greater level of attention. In 2014, more polymers were explored for their foamability, and for generation of nanocomposites. Poly(ɛ-caprolactone), poly(lactic acid) and poly(lactide-co-glycolide) were the most frequently investigated polymers for their porous matrix formation, or particle formation features using supercritical carbon dioxide because of their biomedical significance as biodegradable platforms for tissue engineering scaffolds and drug delivery devices. Poly(ethylene oxide), poly(lactic acid), and poly(methyl methacrylate) were the polymers that were explored in multiple application areas. Based on the close examination of these publications, the review provides specific observations on the advances that are made toward improved understanding of the factors that affect the miscibility of polymers in carbon dioxide, and for further understanding of the synergistic or other effects of components in polymer blends and composites, including the consequences of the presence of crystalline versus amorphous domains and morphological differences, or the consequences of the presence of nanofillers in different applications. New perspectives that are emerging in each application area are presented.
134 citations
TL;DR: In this paper, the compatibility of polyethersulfone (PES)-based blend membranes was investigated through thermodynamics and kinetics analyses, and the effect of SPSf on the compatibility and morphologies of PES-based membranes was characterized by Schneier theory, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), etc.
119 citations
TL;DR: In this article, the authors review computer simulation studies of the fundamental problem of homopolymers structure and dimensions in nanocomposites containing bare or grafted spherical or rod nanoparticles.
Abstract: Over the past two decades polymer nanocomposites have received tremendous interest from industry and academia due to their advanced properties comparative to polymer blends. Many computational studies have revealed that the macroscopic properties of polymer nanocomposites depend strongly on the microscopic polymer structure and conformations. In this article we review computer simulation studies of the fundamental problem of homopolymers structure and dimensions in nanocomposites containing bare or grafted spherical or rod nanoparticles. Experimentally, there is controversy over whether the addition of nanoparticles in a polymer matrix can perturb the polymer chains.
116 citations
TL;DR: In this article, an inverse relationship between mechanical ductility and mobility/molecular ordering in conjugated polymer systems was determined definitively through systematic interrogation of poly(3-hexylthiophene) (P3HT) films with varied degrees of molecular ordering and associated charge transport performance.
Abstract: An inverse relationship between mechanical ductility and mobility/molecular ordering in conjugated polymer systems was determined definitively through systematic interrogation of poly(3-hexylthiophene) (P3HT) films with varied degrees of molecular ordering and associated charge transport performance. The dilemma, whereby molecular ordering required for efficient charge transport conclusively undermines the applicability of these materials for stretchable, flexible device applications, was resolved using a polymer blend approach. Specifically, the molecular interactions between dissimilar polymer materials advantageously induced semiconducting polymer ordering into efficient π–π stacked fibrillar networks. Changes in the molecular environment surrounding the conjugated polymer during the elastomer curing process further facilitated development of high mobility networked semiconductor pathways. A processed P3HT: poly(dimethylsiloxane) (PDMS) composite afforded a semiconducting film that exhibits superior du...
TL;DR: In this article, a poly(e-caprolactone) (PCL)/poly(lactic acid) (PLA) blend is achieved through the adsorption-desorption of polymer chains on the graphene surface.
TL;DR: In this article, the formation of blends prepared via spin-coating in conditions which yield bilayer and trilayer stratifications was investigated, and the authors used a combination of in situ experimental and computational tools to study the competing effects of formulation thermodynamics and process kinetics in mediating the final vertical stratification.
Abstract: Blending of small-molecule organic semiconductors (OSCs) with amorphous polymers is known to yield high performance organic thin film transistors (OTFTs). Vertical stratification of the OSC and polymer binder into well-defined layers is crucial in such systems and their vertical order determines whether the coating is compatible with a top and/or a bottom gate OTFT configuration. Here, we investigate the formation of blends prepared via spin-coating in conditions which yield bilayer and trilayer stratifications. We use a combination of in situ experimental and computational tools to study the competing effects of formulation thermodynamics and process kinetics in mediating the final vertical stratification. It is shown that trilayer stratification (OSC/polymer/OSC) is the thermodynamically favored configuration and that formation of the buried OSC layer can be kinetically inhibited in certain conditions of spin-coating, resulting in a bilayer stack instead. The analysis reveals here that preferential loss of the OSC, combined with early aggregation of the polymer phase due to rapid drying, inhibit the formation of the buried OSC layer. The fluid dynamics and drying kinetics are then moderated during spin-coating to promote trilayer stratification with a high quality buried OSC layer which yields unusually high mobility >2 cm2 V−1 s−1 in the bottom-gate top-contact configuration.
TL;DR: The rheological, mechanical and mucoadhesive properties of the polymeric blends can be manipulated by changing the concentrations of thepolymers and they suggest the blends are worthy of biomedical applications.
Abstract: The development of binary polymeric mixtures (polymer blends) containing bioadhesive and thermoresponsive polymers can provide new materials for biomedical applications, with higher contact, increased adhesion, prolonged residence time, protection, and in determined cases, secured absorption of an active agent from the site of application. Mixtures were prepared using a wide range of poloxamer 407 and Carbopol 971P(®) amounts. The rheological (flow and oscillatory), sol-gel transition temperature, mechanical (hardness, compressibility, adhesiveness, cohesiveness and elasticity), softness, and mucoadhesive properties of formulations were investigated. Moreover, the interaction between the different proportions of polymers was also analyzed. Continuous shear and oscillatory rheometry identified the plastic flow with various degrees of thixotropy, besides the viscoelastic behavior of formulations. The determination of gelation temperature displayed values ranged from 27.17 to 41.09°C. It was also found that low carbomer concentrations were enough to provide positive interaction parameter. However, the highest values were obtained for the polymeric blends with higher concentration of poloxamer 407. The mucoadhesion and softness index were greater in preparations containing 20% (w/w) poloxamer 407. The rheological, mechanical and mucoadhesive properties of the polymeric blends can be manipulated by changing the concentrations of the polymers and they suggest the blends are worthy of biomedical applications.
TL;DR: In this paper, a flexible dielectric composites composed of polyvinyl alcohol (PVA), polyethylene glycol (PEG), and graphene oxide (GO) was developed using facile and eco-friendly colloidal processing technique.
Abstract: Novel flexible dielectric composites composed of polyvinyl alcohol (PVA), polyethylene glycol (PEG), and graphene oxide (GO) with high dielectric constant and low dielectric loss have been developed using facile and eco-friendly colloidal processing technique. The structure and morphology of the PVA/PEG/GO composites were evaluated using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, UV-vis spectroscopy (UV-vis), X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The dielectric behavior of PVA/PEG/GO composites was investigated in the wide range of frequencies from 50 Hz to 20 MHz and temperature in the range 40 to 150 °C using impedance spectroscopy. The dielectric constant for PVA and PVA/PEG (50/50) blend film was found to be 10.71 (50 Hz, 150 °C) and 31.22 (50 Hz, 150 °C), respectively. The dielectric constant for PVA/PEG/GO composite with 3 wt% GO was found to be 644.39 (50 Hz, 150 °C) which is 60 times greater than the dielectric constant of PVA and 20 times greater than the dielectric constant of PVA/PEG (50/50) blend film. The PVA/PEG/GO composites not only show high dielectric constant but also show low dielectric loss which is highly attractive for practical applications. These findings underline the possibilities of using PVA/PEG/GO composites as a flexible dielectric material for high-performance energy storage applications such as embedded capacitors.
TL;DR: In this article, a new amine-containing polymer/zeolite Y composite membrane was successfully synthesized for CO2/N2 separation from flue gas, and the composite membrane with a selective amine layer thickness of more than 200nm showed a better performance compared to the membrane without the zerosilite Y seed layer, which was due to the fact that the ZY layer had a smaller interparticle pore size than the PES substrate.
TL;DR: In this paper, the relationship between donor/acceptor phase separation, domain size, and the resulting photovoltaic characteristics of PDFQx3T and PNDI2OD-T2-based all-PSCs was investigated.
Abstract: The control of the bulk-heterojunction (BHJ) morphology in polymer/polymer blends remains a critical hurdle for optimizing all-polymer solar cells (all-PSCs). The relationship between donor/acceptor phase separation, domain size, and the resulting photovoltaic characteristics of PDFQx3T and P(NDI2OD-T2)-based all-PSCs was investigated. We varied the film-processing solvents (chloroform, chlorobenzene, o-dichlorobenzene, and p-xylene), thereby manipulating the phase separation of all-polymer blends with the domain size in the range of 30–300 nm. The different volatility and solubility of the solvents strongly influenced the aggregation of the polymers and the BHJ morphology of polymer blends. Domain sizes of all-polymer blends were closely correlated with the short-circuit current density (JSC) of the devices, while the open-circuit voltage (0.80 V) and fill factor (0.60) were unaffected. All-PSCs with the smallest domain size of ∼30 nm in the active layer (using chloroform), which is commensurate with the...
TL;DR: Evaluating the effect of reprocessing on the structure and properties of a low density polyethylene/thermoplastic starch (LDPE/TPS) blend compared to LDPE indicated that multiple extrusion steps led to a reduction in the average size of the starch-rich phases of LDPe/TPS blends and minor changes in the mechanical and rheological properties of the materials.
TL;DR: Results revealed that choosing low-hardness TPU or replacing neat PCL layers by TPU/PCL blend with co-continuous morphology were beneficial to achieving outstanding shape memory performances.
Abstract: Shape memory materials containing alternating layers of thermoplastic polyurethane (TPU) and polycaprolactone (PCL) were fabricated through layer-multiplying extrusion. As a type of special co-continuous morphology, the multilayer structure had stable and well-defined continuous layer spaces and could be controlled by changing the number of layers. Compared with conventional polymer blends, the multilayer-assembled system with the same compositions had higher shape-fixing and -recovery ratios that could be further improved by increasing the number of layers. By analyzing from a viscoelastic model, the deformation energy preserved in elastic TPU layers would be balanced by adjacent PCL layers through interfacial shearing effect so that each component in the multilayer structure was capable of endowing the maximum contribution to both of the shape-fixing and -recovery stages. Besides, the influence of the hardness of TPU layers and the morphology of PCL layers were respectively concerned as well. Results revealed that choosing low-hardness TPU or replacing neat PCL layers by TPU/PCL blend with co-continuous morphology were beneficial to achieving outstanding shape memory performances.
TL;DR: This study reports an in depth investigation of the impact of the electrospinning process on the phase separation of a model partially miscible polymer blend, PVP K90 and HPMCAS, in comparison to other conventional solvent evaporation based processes including film casting and spin coating.
Abstract: Electrospun fibrous materials have a wide range of biomedical applications, many of them involving the use of polymers as matrices for incorporation of therapeutic agents. The use of polymer blends improves the tuneability of the physicochemical and mechanical properties of the drug loaded fibers. This also benefits the development of controlled drug release formulations, for which the release rate can be modified by altering the ratio of the polymers in the blend. However, to realize these benefits, a clear understanding of the phase behavior of the processed polymer blend is essential. This study reports an in depth investigation of the impact of the electrospinning process on the phase separation of a model partially miscible polymer blend, PVP K90 and HPMCAS, in comparison to other conventional solvent evaporation based processes including film casting and spin coating. The nanoscale stretching and ultrafast solvent removal of electrospinning lead to an enhanced apparent miscibility between the polymers, with the same blends showing micronscale phase separation when processed using film casting and spin coating. Nanoscale phase separation in electrospun blend fibers was confirmed in the dry state. Rapid, layered, macroscale phase separation of the two polymers occurred during the wetting of the fibers. This led to a biphasic drug release profile from the fibers, with a burst release from PVP-rich phases and a slower, more continuous release from HPMCAS-rich phases. It was noted that the model drug, paracetamol, had more favorable partitioning into the PVP-rich phase, which is likely to be a result of greater hydrogen bonding between PVP and paracetamol. This led to higher drug contents in the PVP-rich phases than the HPMCAS-rich phases. By alternating the proportions of the PVP and HPMCAS, the drug release rate can be modulated.
TL;DR: In this paper, the authors demonstrate that a monolayer of particles jamming at interfaces can effectively suppress coarsening and stabilize the cocontinuous morphology of polyethylene/poly(ethylene oxide) blends.
Abstract: Cocontinuous polymer blends have wide applications. They can form conductive plastics with improved mechanical properties. When one phase is extracted, they yield porous polymer sheets, which can be used as filters or membrane supports. However, the cocontinuous morphology is intrinsically unstable due to coarsening during static annealing. In this study, silica nanoparticles, ∼100 nm diameter, with different wetting properties were melt compounded in polyethylene/poly(ethylene oxide) blends. Calculated wetting coefficients of these particles match well with their phase contact angles and their locations in the blends. We demonstrated that a monolayer of particles jamming at interfaces can effectively suppress coarsening and stabilize the cocontinuous morphology. We also correlated the wettability of individual particles at interface to their coarsening suppression ability and found that the most hydrophobic silica nanoparticle is the most effective to arrest coarsening. Moreover, during annealing, we use...
TL;DR: The role of Joncryl as a compatibilizer for the PLA/PA11 system has been demonstrated by the significant decrease of particle size and interfacial tension as well as the improvement of ductile properties, and a new relaxation peak appeared in the relaxation spectrum, indicating the generation of a copolymer at the polymer-polymer interface.
Abstract: The objective of this study was to gain a deep understanding of composition and compatibilization effects on the properties of entirely sustainably sourced polymer blends based on polylactide (PLA) and polyamide 11 (PA11). Generally, PLA cannot challenge regular commodity polymers due to its weak thermo-mechanical properties and its poor elongation properties. With this work, however, we present a promising route to overcome these drawbacks in order to enhance the processability of PLA: blending the polymer with various compositions of other ductile biopolymers such as PA11, as well as mixing PLA/PA11 blends with various amounts of a chain extender, Joncryl ADR®-4368, containing reactive epoxy functions, in a laboratory-scale twin-screw extruder. The effects on the rheological, morphological and mechanical properties were investigated. Results showed that a “self compatibilization” between PLA and PA11 chains can occur but it was found to be insufficient, contrary to recent work reported in the literature. The role of Joncryl as a compatibilizer for the PLA/PA11 system has been demonstrated by the significant decrease of particle size and interfacial tension as well as the improvement of ductile properties. Moreover, a new relaxation peak appeared in the relaxation spectrum, indicating the generation of a copolymer at the polymer-polymer interface.
TL;DR: In this paper, recent advances in the crystallization of ultrathin films of homopolymers and miscible polymer blends are described, with an emphasis on morphologies and, in the case of blends, on mixtures made of two crystalline polymers.
19 Apr 2016
TL;DR: In this paper, Fourier Transform Infrared (FTIR) and Raman spectroscopy was used to identify alteration of functional group in PLA-PEG400 blend using direct casting to produce matrix film.
Abstract: As a biodegradableplastic, polylactideacid (PLA) can be blended with polyethylene glycol (PEG) to form a polymer blend because PEG has a good miscibility with PLA. Furthermore, this paper study the functional groups of PLA-PEG400 blend using direct casting to produce matrix film. Fourier Transform Infrared (FTIR) and Raman spectroscopy was used to identify alteration of functional group PLA-PEG400 blend. Absorbance and frequency wavenumber were used to observe any changing among functional group. In general, PLA-PEG blend did not produce a new configuration or chemical properties although some functional groups tended to decrease. PLA-PEG400 film spectra showed a similaritycompared to those of neat PLA because of each pristine polymer. However, FTIR and Raman investigated reducing carbonyl group of PLA with PEG400 addition and followed improving CH-COC bonding. Methyl group represented CH3symmetricchanged both the shift and absorbance.FTIR and Raman spectroscopy observed increasing hydrogen bonding with i...
TL;DR: In this article, a rapid electroactive ternary shape memory polymer (SMP) composites containing multiwalled carbon nanotubes (MWCNTs) and two biodegradable polyesters, namely poly(propylene carbonate) (PPC) and poly(lactic acid) (PLA), were presented.
TL;DR: In this paper, the effects of different concentrations of graphene oxide (GO) in the nanocomposite, as well as the role of pH and nanocomposition load in Pb2+ removal were investigated.
Abstract: The present study describes the successful incorporation of graphene oxide (GO) into a binary polymer composite blend of chitosan–poly(acrylic acid) (CS–PAA) to obtain porous hydrogel nanocomposite beads with higher lead removal and regeneration capability than any other chitosan hydrogel material or activated carbon. In the present study, we determine the effects of different concentrations of GO in the nanocomposite, as well as the role of pH and nanocomposite load in Pb2+ removal. The mechanisms of sorption and diffusion of lead in this new nanocomposite, as well as its reusability after regeneration were also investigated. The results show that the addition of GO into the polymer blend has increased significantly the metal uptake capacity owing to the additional oxygen-containing functional groups present in GO and the increase in surface area. Additionally, the solution pH affected the nanocomposite adsorption, with the best adsorption occurring at pH 5. The most economical adsorbent loading was determined to be 37.5 g of hydrogel beads per liter of solution. The pseudo second-order model best described the adsorption kinetics and determined that chemisorption was the mechanism of lead removal. The diffusion mechanism of this new nanocomposite was determined using the intraparticle diffusion model, which suggested that adsorption occurred in three distinct phases. The adsorption isotherms for the hydrogel beads all showed excellent fit to the Langmuir isotherm model. The CS–PAA beads with 5% GO presented the highest Pb2+ adsorption capacity (138.89 mg g−1). When this material was subjected to 3 cycles of adsorption–desorption, relatively high removal values were obtained, indicating good reusability and showing that the GO–CS–PAA nanocomposite beads could be applied to remove lead from water.
TL;DR: In this paper, the ionic conductivity and dielectric properties of PVA/PVP/Li2CO3 polymer blend electrolyte films were investigated using an impedance spectroscopy.
Abstract: New solid polymer blend electrolyte films based on biodegradable polymer blend comprising of polyvinyl alcohol (PVA) and poly (N-vinyl pyrrolidone) (PVP) doped with different wt% of lithium carbonate (Li2CO3) salt have been prepared by solution casting method. The resulting PVA/PVP/Li2CO3 polymer blend electrolyte films have been characterized by various analytical techniques such as FTIR, UV–vis, XRD, TGA, polarized optical microscopy and scanning electron microscopy. The FTIR and XRD analysis confirmed the complex formation between PVA/PVP blend and Li2CO3 salt. The ionic conductivity and the dielectric properties of PVA/PVP/Li2CO3 polymer blend electrolyte films were investigated using an impedance spectroscopy. It was observed that the ionic conductivity of PVA/PVP/Li2CO3 electrolyte system increases as a function of Li2CO3 concentration. The highest ionic conductivity was found to be 1.15 × 10−5 S cm−1 for polymer blend electrolyte with 20 wt% Li2CO3 content. On the other hand, the dielectric results revealed the non-Debye type of behaviour. The dielectric constant values indicate a strong dielectric dispersion in the studied frequency range which increases as the Li2CO3 content increases. The dielectric constant as high as 1200 (e = 1201.57, 50 Hz, 150 °C) and the dielectric loss well below 4 (tan δ = 3.94, 50 Hz, 150 °C) were obtained for polymer blend electrolytes with 25 wt% Li2CO3 salt. Thus, the results obtained in the present study suggest that the PVA/PVP/Li2CO3 polymer blend electrolyte system seems to be a promising candidate for solid state battery applications.
TL;DR: Coating HAp with a polymeric blend composed of Ch and PLGA led to a decrease in the reactivity and antimicrobial activity of the composite particles, but also to an increase in the quality of the newly formed bone tissue in the reconstructed defect area.
TL;DR: In this article, the interfacial properties in polymer blend nanocomposites are calculated by micromechanical modeling of experimental tensile strength and modulus, and the effects of nanofiller content on the interfacer properties are determined.
TL;DR: In this article, the cell structure of polypropylene (PP)/polystyrene (PS) blend foams with a bimodal cell structure were prepared by using supercritical carbon dioxide (scCO 2 ) in continuous extrusion.
Abstract: It is generally difficult to predict the cell structure foamed from a binary polymer blend compared to a single polymer, as many factors in polymer blends add to the complexity of the foaming process without easy control, such as blend morphology, blend viscosity, and solubility and diffusivity of the foaming agent, etc. In this study, polypropylene (PP)/polystyrene (PS) blend foams with a bimodal cell structure were prepared by using supercritical carbon dioxide (scCO 2 ) in continuous extrusion. By comparison of the cell structure of blend foams before and after extraction, it was found that the large cells were mainly formed in PS phase, while the small ones were mostly formed in PP phase. A possible mechanism was proposed to explain the formation of the bimodal cell structure. It was believed that a prominent difference in cell nucleation in the two phases of the PP/PS blends was required for the formation of bimodal cell structure. The proposed mechanism was confirmed by further experimental results, which showed that the bimodal cell structure could be changed by altering the nucleation ability in PP phase and PS phase through changing experimental conditions, such as the content of scCO 2 and the pressure drop, or through applying a heterogeneous nucleating agent.