Showing papers on "Polymer blend published in 2003"
01 Jan 2003
TL;DR: Utracki et al. as mentioned in this paper introduced the concept of polymer blends and their application in the field of polymers and polymers processing, including the use of high energy radiation in Polymer Blends technology.
Abstract: List of Authors. Preface. 1: Introduction to Polymer Blends L.A. Utracki. 2: Thermodynamics of Polymer Blends L.A. Utracki. 3: Crystallization, Morphological Structure and Melting of Polymer Blends G. Groeninckx, M. Vanneste, V. Everaert. 4: Interphase and Compatibilization by Addition of a Compatibilizer A. Ajji. 5: Reactive Compatibilization of Polymer Blends S.B. Brown. 6: Interpenetrating Polymer Networks L.H. Sperling, R. Hu. 7: The Rheology of Polymer Alloys and Blends L.A. Utracki, M.R. Kamal. 8: Morphology. of Polymer Blends T. Inoue. 9: Compounding Polymer Blends L.A. Utracki, G. Z.-H. Shi. 10: Polymer Blends Forming M.M. Dumoulin. 11: Use of High Energy Radiation in Polymer Blends Technology A. Singh, K. Bahari. 12: Properties and Performance of Polymer Blends S.F. Xavier. 13: Applications of Polymer Alloys and Blends J.J. Scobbo Jr., L.A. Goettler. 14: Aging and Degradation of Polymer Blends J.M.G. Cowie, I.J. McEwen, R. McIntyre. 15: Commercial Polymer Blends M.K. Akkapeddi. 16: Role of Polymer Blends' Technology in Polymer Recycling L.A. Utracki. 17: Perspectives in Polymer Blend Technolog L.M. Robeson. Appendix 1: International Abbreviations for Polymers and Polymer Processing, compiled by L.A. Utracki. Appendix 2: Miscible Polymer Blends, prepared by S. Krause, S.H. Goh. Appendix 3: Examples of Commercial Blends, compiled by L.A. Utracki. Appendix 4: Dictionary of Terms Used in Polymer Science and Technology, compiled by L.A. Utracki. Subject index.
754 citations
TL;DR: A survey of the available information on the environmental fate of polyvinyl alcohol (PVA) and PVA-based materials can be found in this paper, where the biochemistry and microbial physiology of PVA biodegradation and on the influence of environmental conditions are discussed along with the biodegrading processes of other water-soluble materials.
744 citations
TL;DR: In this paper, the authors show that photovoltaic devices fabricated from blends of branched CdSe nanoparticles and a conjugated polymer give improved performance compared with devices made from nanorod/polymer blends.
Abstract: We show that photovoltaic devices fabricated from blends of branched CdSe nanoparticles and a conjugated polymer give improved performance compared with devices made from nanorod/polymer blends. The improvement is consistent with improved electron transport perpendicular to the plane of the film. Solar power conversion efficiencies of 1.8% were achieved under AM1.5 illumination for a device containing 86 wt % of nanoparticles.
648 citations
TL;DR: In this paper, the intercalation of the polymer chains between the aluminosilicates layers and morphological structure of the filled PLAs were analyzed by wide-angle X-ray scattering (WAXS).
462 citations
TL;DR: The efficiencies of solar cells using two-component particles are comparable to those of devices prepared from solution at comparable illumination conditions, and that they are not affected by the choice of solvent used in the miniemulsion process.
Abstract: Polymer layers can exhibit significantly improved performances if they possess a multicomponent phase-separated morphology. We present two approaches to control the dimensions of phase separation in thin polymer-blend layers; both rely on polymer nanospheres prepared by the miniemulsion process. In the first approach, heterophase solid layers are prepared from an aqueous dispersion containing nanoparticles of two polymers, whereas in the second approach, both polymers are already contained in each individual nanoparticle. In both cases, the upper limit for the dimension of phase separation is determined by the size of the individual nanoparticles, which can be adjusted down to a few tens of nanometres. We also show that the efficiencies of solar cells using two-component particles are comparable to those of devices prepared from solution at comparable illumination conditions, and that they are not affected by the choice of solvent used in the miniemulsion process.
398 citations
TL;DR: In this article, a review of the properties of immiscible polymer blends is presented, together with models that describe them and their behavior in high volume fractions or with strongly non-Newtonian phases.
Abstract: Microstructure in an immiscible polymer blend consists of the size, shape, and orientation of the phases. Blends exhibit many interesting behaviors, including enhanced elasticity at small strains, drop-size hysteresis, enhanced shear thinning, and stress relaxation curves whose shapes are sensitive to deformation history. These behaviors are directly related to changes in the microstructure, which result from phase deformation, coalescence, retraction, and different types of breakup. These phenomena are reviewed, together with models that describe them. Rheological measurements can probe the microstructure because microstructure contributes directly to stress through interfacial tension. Rheo-optical experiments also provide important insights. Droplet theories explain most of the phenomena for Newtonian phases at low concentrations. Behaviors at high volume fractions or with strongly non-Newtonian phases are less well understood.
391 citations
TL;DR: In this paper, the open circuit voltage of the P3OT-based organic photovoltaic devices was found to be 075 V, which is larger than the theoretical limit calculated by the metal-insulator-metal (MIM) model.
Abstract: Organic photovoltaicdevices based on the bulk heterojunction concept, containing a blend of single-wall carbon nanotubes(SWNTs) and soluble polythiophenes (P3OT) were studied The open circuit voltage V oc of the devices was found to be 075 V, which is larger than the theoretical limit calculated by the metal–insulator–metal (MIM) model In order to investigate the origin of this unusually high V oc , we have prepared P3OT–SWNT based devices with different metal negative electrodes The V oc measured is only very weakly dependent on the work function of the metal, suggesting that the MIM model does not apply in this case From the analysis of the current–voltage characteristics and electron microscopy imaging of the composite structure, it is proposed that the photovoltaic response of these devices is based on the introduction of internal polymer/nanotube junctions within the polymer matrix, which due to a photoinduced electron transfer from the polymer to the nanotube contribute to enhanced charge separation and collection The data suggest that the negligible influence of the negative electrodework function on V oc can be explained by the metal negative electrode forming ohmic contacts to the nanotube percolation paths
364 citations
321 citations
Journal Article•
TL;DR: A series of blends of the biodegradable polymers poly(D,L-lactic acid) and poly( epsilon -caprolactone) were prepared by varying mass fraction across the range of compositions.
Abstract: A series of blends of the biodegradable polymers poly(D,L-lactic acid) and poly( epsilon -caprolactone) were prepared by varying mass fraction across the range of compositions. Tensile testing was performed at room temperature using an extensometer and the elastic modulus was calculated for each blend. The blends were also tested to failure, and the strain-at-failure and yield stress recorded. While the blend has been shown to have a lower critical solution temperature, the mechanical properties were insensitive to the annealing conditions. Scanning electron microscopy was used to characterize the blend microstructure and poor adhesion was observed at the interface between blend components. Differential scanning calorimetry was performed but the results were somewhat variable, indicating this blend may have complex phase behavior that depends sensitively on the method of preparation. However, nuclear magnetic resonance data indicate the two components are phase separated. A percolation model is used to explain the observed mechanical data and the results are consistent with the predictions of the Kerner-Uemura-Takayangi model. The results of these experiments demonstrate the utility of polymer blending in tuning material properties.
292 citations
TL;DR: It appears that in the case of the graft copolymer the improvement in the properties comes from suppression of the crystallinity of each component and not from component interactions, and blending may be a more efficient way to improve ductility of chitosan.
278 citations
TL;DR: In this article, a review of various ways of preparation of liquid crystal/polymer blends and composites leading to their required applications is presented. But the most important features of polymers which can be used as components of blends or composites with liquid crystals include: their film formation ability, high transparency, amorphicity, inertness in relation to a liquid crystal, good miscibility with liquid state and immiscibility in a solid state.
TL;DR: The floating behavior of the low density drug delivery systems could be combined with accurate control of the drug release patterns and could effectively be modified by varying the "matrix-forming polymer/foam powder" ratio.
TL;DR: Supercritical fluid impregnation of polymeric materials stems from the opportunity to utilize high diffusivity, low surface tension and the ease of solvent recovery for the preparation of new polymeric material as discussed by the authors.
Abstract: The interest in the supercritical fluid impregnation of polymeric materials stems from the opportunity to utilize high diffusivity, low surface tension and the ease of solvent recovery for the preparation of new polymeric materials. This term includes a wide range of applications of the supercritical impregnation process that will be discussed in this review: preparation of drug delivery systems via impregnation of an active principle in a polymer matrix, dye and organic metallic complexes impregnation and polymer blends preparation via impregnation of a monomer and an initiator in a swollen polymer matrix.
TL;DR: In this paper, the properties of polymer-organoclay composites prepared by melt-blending of polystyrene (PS), poly(methyl methacrylate) (PMMA), and PS/PMMA blends with Cloisite® organoclays were examined by transmission electron microscopy, X-ray scattering, secondary ion mass spectroscopy, differential scanning calorimetry, and rheological techniques.
Abstract: Morphology, thermal and rheological properties of polymer-organoclay composites prepared by melt-blending of polystyrene (PS), poly(methyl methacrylate) (PMMA), and PS/PMMA blends with Cloisite® organoclays were examined by transmission electron microscopy, small-angle X-ray scattering, secondary ion mass spectroscopy, differential scanning calorimetry, and rheological techniques. Organoclay particles were finely dispersed and predominantly delaminated in PMMA-clay composites, whereas organoclays formed micrometer-sized aggregates in PS-clay composites. In PS/PMMA blends, the majority of clay particles was concentrated in the PMMA phase and in the interfacial region between PS and PMMA. Although incompatible PS/PMMA blends remained phase-separated after being melt-blended with organoclays, the addition of organoclays resulted in a drastic reduction in the average microdomain sizes (from 1–1.5 μm to ca. 300–500 nm), indicating that organoclays partially compatibilized the immiscible PS/PMMA blends. The effect of surfactant (di-methyl di-octadecyl-ammonia chloride), used in the preparation of organoclays, on the PS/PMMA miscibility was also investigated. The free surfactant was more compatible with PMMA than with PS; the surfactant was concentrated in PMMA and in the interfacial region of the blends. The microdomain size reduction resulting from the addition of organoclays was definitely more significant than that caused by adding the same amount of free surfactant without clay. The effect of organoclays on the rheological properties was insignificant in all tested systems, suggesting weak interactions between the clay particles and the polymer matrix. In the PS system, PMMA, and organoclay the extent of clay exfoliation and the resultant properties are controlled by the compatibility between the polymer matrix and the surfactant rather than by interactions between the polymer and the clay surface. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 44–54, 2003
TL;DR: In this article, a one-step combined twin-screw/single screw extrusion setup is used to carry out the melt-melt mixing of polyethylene/thermoplastic starch blends.
TL;DR: Although the PVA/lignin blend system is immiscible in the bulk, the results herein show the existence of some specific intermolecular interaction between PVA and lignin.
TL;DR: In this paper, an all-polymer high-dielectric composite material fabricated by a combination of conductive polyaniline particles (K>105) within a poly(vinylidene fluoride-trifluoroethylene-chlorotrifluorethylene) terpolymer matrix was presented.
Abstract: We report here an all-polymer high-dielectric (dielectric constant K>1000 at 1 kHz) percolative composite material, fabricated by a combination of conductive polyaniline particles (K>105) within a poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) terpolymer matrix (K>50). These high-K polymer hybrid materials also exhibit high electromechanical responses. For example, 1.5% strain, which is proportional to the square of the field applied, can be induced by a field of 9.5 MV/m, an eightfold reduction in field applied compared with that in a fluoroterpolymer matrix.
TL;DR: The effect of cooling rate on crystallization and subsequent aging of high stereoregular poly(lactide) (PLA) blended with poly(ethylene glycol) (PEG) was studied by thermal analysis and by direct observation of the solid state structure with atomic force microscopy (AFM) as discussed by the authors.
TL;DR: In this paper, a chitosan-polyvinyl alcohol (PVA) blend films were prepared and characterized for mechanical and optical properties using FTIR, and the moisture content increased with increase in PVA concentration.
TL;DR: In this paper, different formulations of biodegradable starch-polyester blend nanocomposite materials have been film blown on a pilot scale film blowing tower, and the physical properties of different films have been examined by thermal and mechanical analysis and X-ray diffraction.
Abstract: Different formulations of biodegradable starch-polyester blend nanocomposite materials have been film blown on a pilot scale film blowing tower The physical properties of different films have been examined by thermal and mechanical analysis and X-ray diffraction The results show that the addition of an organoclay (from 0 to 5 wt%) significantly improves both the processing and tensile properties over the original starch blends Wide angle X-ray diffraction (WAXD) results indicate that the best results were obtained for 30wt% starch blends, and the level of delamination depends on the ratio of starch to polyester and amount of organoclay added The crystallisation temperature of the nanocomposite blends is significantly lower than the base blend This is probably due to the platelets inhibiting order, and hence crystallisation, of the starch and polyester The mechanical and thermal properties of the blends are also sensitive to the way the clay particles are dispersed (C) 2003 Society of Chemical Industry
TL;DR: In this paper, a single-layer polymer light-emitting diodes fabricated from binary blends of conjugated poly(9,9-dioctylfluorene) with either thermally stable poly(vinyl diphenylquinoline) (PVQ) or polystyrene was obtained.
Abstract: Spectrally stable blue electroluminescence (EL) is obtained from single-layer polymer light-emitting diodes fabricated from binary blends of conjugated poly(9,9-dioctylfluorene) (PFO) with either thermally stable poly(vinyl diphenylquinoline) (PVQ) or polystyrene. The brightness and EL efficiency of the polymer blend LEDs were enhanced by a factor of 5−14 compared to the PFO homopolymer devices. The additional green emission observed in the EL spectra of pure PFO devices was substantially suppressed in the blend LEDs. The electrical characteristics of the diodes and electric-field-modulated PL spectroscopy results indicate increased spatial confinement induced exciton stability and electron−hole recombination efficiency in the blend devices. The variation of the device performance with blend composition is related to the phase-separated morphology of the blends. The origin of the spectral stability lies in the improved thermal stability of the PFO:PVQ blends due to the high glass transition temperature (T...
TL;DR: In this article, the effect of the binary interaction parameter, χ, on Tg was analyzed, in which specific intermolecular interactions exist, and a strong hydrogen bond between the aromatic hydroxyl proton and the ether oxygen in PEO.
Abstract: Polymer blending is a convenient method to develop products with desirable properties. Through specific intermolecular interactions favorable polymer blending can occur, and composite materials with desirable properties can be produced. In this study we have prepared poly(ethylene oxide)−lignin blends using thermal mixing. Miscible blends were observed over the entire blend ratio. A melting point depression, comparable to results obtained from phenoxy/PEO blends, and a negative deviation of Tg from the weight-average values was observed. The effect of the binary interaction parameter, χ, on Tg was analyzed. Satisfactory prediction of the Tg−composition curve was obtained, in which specific intermolecular interactions exist. FT-IR analyses revealed a strong hydrogen bond between the aromatic hydroxyl proton and the ether oxygen in PEO.
TL;DR: In this paper, the mixture of amorphous poly(DL-lactide) and poly(methyl methacrylate) (PMMA) was examined by differential scanning calorimetry.
Abstract: Blends of amorphous poly(DL-lactide) (DL-PLA) and crystalline poly(L-lactide) (PLLA) with poly(methyl methacrylate) (PMMA) were prepared by both solution/precipitation and solution-casting film methods. The miscibility, crystallization behavior, and component interaction of these blends were examined by differential scanning calorimetry. Only one glass-transition temperature (Tg) was found in the DL-PLA/PMMA solution/precipitation blends, indicating miscibility in this system. Two isolated Tg's appeared in the DL-PLA/PMMA solution-casting film blends, suggesting two segregated phases in the blend system, but evidence showed that two components were partially miscible. In the PLLA/PMMA blend, the crystallization of PLLA was greatly restricted by amorphous PMMA. Once the thermal history of the blend was destroyed, PLLA and PMMA were miscible. The Tg composition relationship for both DL-PLA/PMMA and PLLA/PMMA miscible systems obeyed the Gordon–Taylor equation. Experiment results indicated that there is no more favorable trend of DL-PLA to form miscible blends with PMMA than PLLA when PLLA is in the amorphous state. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 23–30, 2003
TL;DR: The use of scanning near-field optical microscopy, scanning force microscopy and nuclear-reaction analysis to study the structure of a thin film of a phase-separated blend of two conjugated polymers prepared by spin-casting shows that in addition to the well-known micrometre-scale phase- separation morphology, one of the polymers preferentially wets the surface and forms a 10-nm-thick, partially crystallized wetting layer.
Abstract: Blends of conjugated polymers are frequently used as the active semiconducting layer in light-emitting diodes and photovoltaic devices. Here we report the use of scanning near-field optical microscopy, scanning force microscopy and nuclear-reaction analysis to study the structure of a thin film of a phase-separated blend of two conjugated polymers prepared by spin-casting. We show that in addition to the well-known micrometre-scale phase-separated morphology of the blend, one of the polymers preferentially wets the surface and forms a 10-nm-thick, partially crystallized wetting layer. Using near-field microscopy we identify unexpected changes in the fluorescence emission from the blend that occurs in a 300-nm-wide band located at the interface between the different phase-separated domains. Our measurements provide an insight into the complex structure of phase-separated conjugated-polymer thin films. Characterizing and controlling the properties of the interfaces in such films will be critical in the further development of efficient optoelectronic devices.
TL;DR: A route for producing semiconducting polymer blends is demonstrated in which a doped pi-conjugated polymer is forced into a three-dimensionally continuous minor phase by the self-assembly of colloidal particles and block copolymers.
Abstract: A route for producing semiconducting polymer blends is demonstrated in which a doped pi-conjugated polymer is forced into a three-dimensionally continuous minor phase by the self-assembly of colloidal particles and block copolymers. The resulting cellular morphology can be viewed as a high-internal phase polymeric emulsion. Compared with traditional blending procedures, this process reduces the percolation threshold for electrical conductivity by a factor of 10, increases the conductivity by several orders of magnitude, and simultaneously improves thermal stability. Following this route, new applications can be envisaged for semiconducting polymer blends that require only minimal concentrations of doped pi-conjugated polymer.
TL;DR: In this paper, a detailed characterization of the electronic and optical properties of polyfluorene chains and compared them to those in copolymers containing alternating fluorene and benzothiadiazole or ethylenedioxythiophene units.
Abstract: We report a detailed quantum-chemical characterization of the electronic and optical properties of polyfluorene chains and compare them to those in copolymers containing alternating fluorene and benzothiadiazole or ethylenedioxythiophene units. The introduction of the comonomer can strongly modify the excitonic properties as well as the efficiency of charge- and energy-transfer processes. The choice of the comonomer is thus critical in targeting specific optical properties while maintaining good transport properties.
TL;DR: In this article, thermoplastic starch/natural rubber polymer blends were prepared using directly natural latex and cornstarch, with natural rubber content varying from 2.5 to 20%.
TL;DR: In this article, a detailed analysis of the various factors that contribute to increase or decrease the growth rate of spherulites is reported and supported by several examples, mainly with regard to miscibility of the components.
TL;DR: In this paper, the dispersion of carbon black in an immiscible polymer blend of poly-(methyl methacrylate) (PMMA) and polypropylene (PP) was studied as the viscosity of PMMA increased.
Abstract: The dispersion of carbon black (CB) in an immiscible polymer blend of poly-(methyl methacrylate) (PMMA) and polypropylene (PP) was studied as the viscosity of PMMA increased. It was found that the dispersion of carbon black was strongly influenced by the viscosity of PMMA. The CB was dispersed in the PMMA phase when the viscosities of PMMA and PP are comparable, as predicted by Sumita's model. As the viscosity of PMMA increases, the CB was found to be located at the interface between the PMMA and PP phases. On further increase in the viscosity of PMMA, the CB was found to be dispersed in the PP phase. In addition, the CB dispersion in the PP/PMMA blends can significantly influence the positive temperature coefficient (PTC) intensity of the blends.
TL;DR: In this article, the authors present a survey of commercially available instrumentation for inkjet printing of polymer micro-arrays for combinatorial materials research, and the requirements of these instruments.
Abstract: This article reviews commercially available instrumentation for inkjet printing of polymer micro-arrays for combinatorial materials research, and requirements thereof. These include a print head positioning accuracy better than 10 μm and a minimum drop volume of 100 pL. Commercially available instruments that fulfill these requirements can be divided into two categories, depending on whether they receive ink from a reservoir (dispense mode) or through fluid aspiration (pipette mode). Instruments belonging to the first category are restricted to the preparation of polymer blend micro-arrays. These consist of a few substances mixed in various ratios. The other instruments can be used for the preparation of both micro-arrays of large numbers of different pure polymer compounds and polymer blend micro-arrays. Moreover, ways to mix compounds are discussed.