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PBT/PS Blend (ps + blend)
Selected AbstractsShear-induced migration of nanoclay during morphology evolution of PBT/PS blendJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Joung Sook Hong Abstract In this study, we investigated clay migration and its localization in multiphase blend nanocomposite systems during the evolution of blend morphology to elucidate how a hydrodynamic stress and chemical affinity between the polymer and clay induce them. To observe the morphology evolution, a multilayered blend, alternatively superposed poly(butylenes terephthalate) (PBT) and polystyrene (PS)/clay films or PBT/clay and PS films, was subjected to homogeneous shear flow, 1 s,1. Furthermore, the morphology was observed at different shear rates 1 s,1. When the PBT/(PS/clay) multilayered blend is subjected to flow, the clay dispersed in the PS layer first migrates to the interface depending on the amount of applied strain. The clay at the interface causes the average drop size of blend morphology to become smaller and the blend morphology becomes more stable because of the coalescence suppression effect. As more shear is applied, the clay at the interface moves further into more compatible phase, PBT, although the viscosity of PBT is higher than PS. On the contrary, the clay in the PBT layer does not migrate to the PS phase at any shear rate, which means that its chemical affinity is strong enough to prevent shear-induced migration. The clay increases the viscosity of the PBT phase and results in a different morphology with a droplet, cocontinuous structure. As a result, when the clay is induced to migrate by hydrodynamic stress, it migrates into thermodynamically more stable positions at the interface or in the chemically more compatible phase, depending on the applied strain. Once it is located at a thermodynamically more stable position, it is difficult to push it out only by hydrodynamic stress. The location of clay is significantly affected by the morphology during evolution, which means that the blend morphology can control the droplet form and cocontinuous structure by control of the clay migration kinetics. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Effects of bulk morphology on the mechanical properties of melt-blended PP/PS blendsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Kazuhiro Yoshida Abstract We investigated the relationship between morphology and mechanical properties in binary blends of isotactic polypropylene (PP) and atactic polystyrene (PS) showing completely phase-separated morphology. The domain size and crystallinity in PP phase were controlled by the comp-molding conditions such as holding time in the hot-press and quenching temperature to prepare the sheets. The phase-inversion took place at 62.5 wt % of PS content and this leads to ductile-brittle transition at the blend composition. It was found that the mechanical properties of PP-rich blends are dominantly affected by the nature of the PP matrix and independent of the domain size of PS phase. This is associated with the interfacial separation between rigid PS droplets and PP matrix. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Deformation mechanism of polystyrene toughened with sub-micrometer monodisperse rubber particlesPOLYMER INTERNATIONAL, Issue 11 2006Guanghui Gao Abstract Core,shell polybutadiene- graft -polystyrene (PB- g -PS) rubber particles with different ratios of polybutadiene to polystyrene were prepared by emulsion polymerization through grafting styrene onto polybutadiene latex. The weight ratio of polybutadiene to polystyrene ranged from 50/50 to 90/10. These core-shell rubber particles were then blended with polystyrene to prepare PS/PB- g -PS blends with a constant rubber content of 20 wt%. PB- g -PS particles with a lower PB/PS ratio (,70/30) form a homogeneous dispersion in the polystyrene matrix, and the Izod notched impact strength of these blends is higher than that of commercial high-impact polystyrene (HIPS). It is generally accepted that polystyrene can only be toughened effectively by 1,3 µm rubber particles through a toughening mechanism of multiple crazings. However, the experimental results show that polystyrene can actually be toughened by monodisperse sub-micrometer rubber particles. Scanning electron micrographs of the fracture surface and stress-whitening zone of blends with a PB/PS ratio of 70/30 in PB- g -PS copolymer reveal a novel toughening mechanism of modified polystyrene, which may be shear yielding of the matrix, promoted by cavitation. Subsequently, a compression-induced activation method was explored to compare the PS/PB- g -PS blends with commercial HIPS, and the result show that the toughening mechanisms of the two samples are different. Copyright © 2006 Society of Chemical Industry [source] Reactively and physically compatibilized immiscible polymer blends: stability of the copolymer at the interfaceMACROMOLECULAR SYMPOSIA, Issue 1 2003Charef Harrats Abstract This paper reports on the interfacial behaviour of block and graft copolymers used as compatibilizers in immiscible polymer blends. A limited residence time of the copolymer at the interface has been shown in both reactive blending and blend compatibilization by preformed copolymers. Polystyrene (PS)/polyamide6 (PA6), polyphenylene oxide (PPO)/PA6 and polymethylmethacrylate (PMMA)/PA6 blends have been reactively compatibilized by a styrene-maleic anhydride copolymer SMA. The extent of miscibility of SMA with PS, PPO and PMMA is a key criterion for the stability of the graft copolymer at the interface. For the first 10 to 15 minutes of mixing, the in situ formed copolymer is able to decrease the particle size of the dispersed phase and to prevent it from coalescencing. However, upon increasing mixing time, the copolymer leaves the interface which results in phase coalescence. In PS/LDPE blends compatibilized by preformed PS/hydrogenated polybutadiene (hPB) block copolymers, a tapered diblock stabilizes efficiently a co-continuous two-phase morphology, in contrast to a triblock copolymer that was unable to prevent phase coarsening during annealing at 180°C for 150 minutes. [source] Reactive blending of poly (dimethylsiloxane) with nylon 6 and poly (styrene):Effect of reactivity on morphologyPOLYMER ENGINEERING & SCIENCE, Issue 4 2001M. Mari Reactive compatibilization was used to control and stabilize 20,30wt% poly(dimethylsioxane) (PDMS) dispersions in nylon 6 (PA) and poly(styrene) (PS), respectively. The effect of the type of reation (amine (NH2)/anhydride (An), NH2/ epoxy(E) and carboxylic acid (COOH)/E) on the morphology was studied with electron microscopy. PS and PDMS have mutual solvents thus it was possible to use gel permeation chromatography (GPC) to determine the concentration of block copolymer in PS/PDMS blends. Reactive blending of PA6 with difunctional PDMS-(AN)2 did not decrease the PDMS particle size compared to the non-reactive blend (,10,m). Particle size decreaeased significantly to about 0.5 ,m when PA6 was blended with a PDMS containing about 4 random An groups along the chain. For the PS/PDMS blends, GPC revealed that the NH2/An reaction formed about 3% block copolymer and produced stable PDMS particles , 0.4 ,m. No reaction was detected for the PS-NH2/PDMS-E blend and the morphology was coarse and unstable. Also, PS-NH2/PDMS-An reactivity was lower compared to other systems such as PS/ poly (isoprene) and PS/poly(methaacrylte) using the same reaction. This was attributed to the relatively thinner PS/PDMS interface dueto the high PS/PDMs immiscibility. [source] Effect of mixing protocol on compatibilized polymer blend morphologyPOLYMER ENGINEERING & SCIENCE, Issue 5 2006Bin Lin We investigated the effect of mixing protocol on the morphology of compatibilized polymer blends made with premade compatibilizer and reactively formed in-situ compatibilizer in a custom-built miniature mixer Alberta Polymer Asymmetric Minimixer (APAM). The compatibilized blends show a finer morphology than uncompatibilized blends if the polymers are mixed together in the dry state and then fed into the mixer. It is found that premelting one polymer, and premixing polymers and compatibilizer, both greatly affect the compatibilized blends' morphology. The effects are complex since the dispersed phase particle size and distribution of the compatibilized blends may be smaller or larger when compared with the uncompatibilized system, depending on the material's physical and chemical properties; for example, diblock molecular weight or the preference of copolymer to migrate to a particular phase can change the final morphology. Good mobility of the copolymer to reach the interface is crucial to obtain a finer morphology. Micelles are observed when a high molecular weight diblock copolymer P(S- b -MMA) is used for a PS/PMMA blend. Because of its enhanced mobility, no micelles are found for a low molecular weight diblock copolymer P(S- b -MMA) in a PS/PMMA blend. For PS/PE/P(S- b -E) blends, finer morphology is obtained when P(S- b -E) is first precompounded with PS. Because the block copolymer prefers the PE phase, if the P(S- b -E) block copolymer is compounded with PE first, some remains inside the PE phase and does not compatibilize the interface. In the case of reactive blend PSOX/PEMA, premelting and holding the polymers at high temperature for 5 min decreases final dispersed phase particle size; however, premelting and holding for 10 min coarsens the morphology. POLYM. ENG. SCI. 46:691,702, 2006. © 2006 Society of Plastics Engineers. [source] Phase separation of polymer-functionalized SWNTs within a PMMA/polystyrene blendJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 2 2009James D. Mayo Abstract Phase separation of polystyrene (PS) and poly(methyl methacrylate) (PMMA) blends was used as a means to segregate PS- or PMMA-functionalized single-walled carbon nanotubes (SWNTs) in thin films. Dilute solutions (5 wt % in THF) of 1:1 PS/PMMA blends containing the functionalized nanotubes were spin cast and annealed at 180 °C for 12 h. Two different polymer molecular weights were used (Mn = 8000 or Mn = 22,000), and were of approximately equivalent molecular weight to those attached to the surface of the nanotubes. Nanotube functionalization was accomplished using the Cu(I)-catalyzed [3 + 2] Huisgen cycloaddition, in which alkyne-decorated nanotubes were coupled with azide-terminated polymers, resulting in polymer-SWNT conjugates that were soluble in THF. Characterization of the annealed films by scanning Raman spectroscopy, which utilized the unique Raman fingerprint of carbon nanotubes, enabled accurate mapping of the functionalized SWNTs within the films relative to the two phase-separated polymers. It was found that nanotube localization within the phase-separated polymer films was influenced by the type of polymer attached to the nanotube surface, as well as its molecular weight. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 450,458, 2009 [source] Effect of ,-irradiation on the physical properties and dyeability of poly(vinyl butyral) blends with polystyrene and poly(ethylene glycol)POLYMER COMPOSITES, Issue 6 2008Horia M. Nizam El-Din Cast films of polymer blends essentially based on poly(vinyl butyral) (PVB) and equal ratios of polystyrene (PS) and poly(ethylene glycol) (PEG) were prepared from benzene and butyl alcohol solutions of the individual polymers. The effect of ,-irradiation on the thermal decomposition and tensile mechanical properties was investigated. Moreover, the effect of ,-irradiation on the dye affinity of PVB/PS and PVB/PEG for basic and acid dyestuffs was studied. The thermogravimetric analysis (TGA) study showed that the unirradiated PVB polymer films prepared in benzene displayed higher thermal stability than the same polymer films prepared in butanol. However, in all cases the thermal stability was found to increase with increasing ,-irradiation dose. On the other hand, PVB/PS blend possesses higher thermal stability than PVB/PEG, as shown from the determination of the weight loss (%) at different heating temperatures, the temperatures of the maximum rate of reaction and the activation energy. While, pure PS films showed the stress-strain behavior of brittle polymers, PVB/PS films showed the behavior of tough polymers with yielding properties. The results of dyeing clearly showed that the solvent type, blend composition, and irradiation dose are determining factors for the dye affinity for basic or acid dyes. For example, unirradiated PVB films prepared from butanol displayed a higher affinity for the basic and acid dyes than the same polymer prepared from the same benzene. However, PVB prepared from butanol showed higher affinity to the dyes than PS prepared from the same solvent. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers [source] Macroscopically Aligned Ionic Self-Assembled Perylene-Surfactant Complexes within a Polymer Matrix,ADVANCED FUNCTIONAL MATERIALS, Issue 13 2008Ari Laiho Abstract Ionic self-assembled (ISA) surfactant complexes present a facile concept for self-assembly of various functional materials. However, no general scheme has been shown to allow their overall alignment beyond local polydomain-like order. Here we demonstrate that ionic complexes forming a columnar liquid-crystalline phase in bulk can be aligned within polymer blends upon shearing, taken that the matrix polymers have sufficiently high molecular weight. We use an ISA complex of N,N,-bis(ethylenetrimethylammonium)perylenediimide/bis(2-ethylhexyl) phosphate (Pery-BEHP) blended with different molecular weight polystyrenes (PS). Based on X-ray scattering studies and transmission electron microscopy the pure Pery-BEHP complex was found to form a two-dimensional oblique columnar phase where the perylene units stack within the columns. Blending the complex with PS lead to high aspect ratio Pery-BEHP aggregates with lateral dimension in the mesoscale, having internal columnar liquid-crystalline order similar to the pure Pery-BEHP complex. When the Pery-BEHP/PS blend was subjected to a shear flow field, the alignment of perylenes can be achieved but requires sufficiently high molecular weight of the polystyrene matrix. The concept also suggests a simple route for macroscopically aligned nanocomposites with conjugated columnar liquid-crystalline functional additives. [source] | ||||||||||