Showing papers on "Miscibility published in 1992"
TL;DR: In this article, the relationship between the miscibility and transesterification in the individual blend pairs is detailed in a review, including polyester liquid crystals, and a variety of polyester blends are discussed.
301 citations
TL;DR: In this article, a new criterion is proposed based on the classical Huggins equation and the huggins coefficient K(m) in the blends, which is reasonable and suitable to predict polymer-polymer miscibility by the viscometry method.
180 citations
TL;DR: In this article, the glass transition temperature and mechanical properties of binary mixtures of the food biopolymers amylopectin, casein and gluten have been studied in the ratio 1:1 in the presence of water.
119 citations
TL;DR: In this article, the relaxation dynamics in miscible blends of PEO and PMMA ranging in composition from 20 to 60 wt% of PMMA were studied subsequent to a linear step strain using the simultaneous measurement of infrared dichroism and birefringence.
Abstract: Relaxation dynamics in miscible blends of PEO and PMMA ranging in composition from 20 to 60 wt% of PMMA are studied subsequent to a linear step strain using the simultaneous measurement of infrared dichroism and birefringence. From the temperature and composition dependences of component relaxation times it is clear that each component of the blend retains a separate rheological identity. Component relaxation dynamics shows a dramatic and complex sensitivity to blend composition. In PMMA-rich blends each component adopts a separate friction factor with a unique temperature dependence
112 citations
TL;DR: In this paper, the effect of shear flow on the phase behavior of partially miscible polymer blends exhibiting a lower critical solution temperature behavior was investigated, with and without the application of flow, using light scattering and as a shift in the glass transition temperature.
106 citations
TL;DR: In this article, the thermal behavior and miscibility of poly(3-hydroxybutyrate) (P(3HB)/poly(vinyl alcohol) blend films prepared by casting have been analyzed by d.s.c., n.r.
101 citations
TL;DR: In this article, a ternary blend composed of poly(ether imide) (PEI), poly (ether ether ketone) (PEEK) and a liquid crystalline polymer (LCP; HX4000, Du Pont).
94 citations
TL;DR: In this paper, anionically prepared monodisperse 1,2-polybutadiene and polyisoprene blends are studied over a wide temperature range and individual relaxations of the components are observed.
Abstract: DSC data show that anionically prepared monodisperse 1,2-polybutadiene (>99% 1,2; 1,2-PBd) and polyisoprene (93% 1,4; PI) are miscible but the glass transition region is very broad for blends with high 1,2-PBd content. The viscoelastic properties of the blends have been studied over a wide temperature range. Individual relaxations of the components are observed. The blends are thermorheologically complex because the temperature dependence of the 1,2-PBd relaxation is stronger than that of PI. Analysis of the temperature dependence of the relaxation times suggests that each component in the blend experiences its own T g
89 citations
TL;DR: In this paper, a mixture of lightly sulfonated polystyrene (10.1 mol % sulfonation) neutralized with zinc (ZnSPS) and nylon-6 (N6) were found to be miscible over the entire compositional range.
Abstract: Blends of a lightly sulfonated polystyrene (10.1 mol % sulfonation) neutralized with zinc (ZnSPS) and nylon-6 (N6) were found to be miscible over the entire compositional range. Miscibility was a coneequence of transition metal complexation between the metal sulfonate and the amide groups. Melting point depression data gave a value for the polymer-polymer interaction parameter of x = -1.3, which indicates very strong intermolecular interactions. FTIR and SAXS analyses indicated that the polyamide effectively solvated the ionic associations in the blends. (ZnSPS). Differential scanning calorimetry (DSC) was used to determine miscibility and x. Fourier transform infrared spectroscopy (FTIR) was used to characterize the local environment of the Zn sulfonate groups as a function of the blend composition. This yielded infor- mation about the specific interactions between ZnSPS and N6 as well as about the ionic associations within ZnSPS. Small-angle X-ray scattering (SAXS) was em- ployed to investigate the microstructural changes in the blends, specifically the effect on the cluster morphology. Experimental Section
85 citations
TL;DR: In this article, the authors investigated the miscibility and domain structure of poly(vinyl alcohol)/poly (vinylpyrrolidone) (PVA/PVP) blends by high-resolution solid-state 13 C nuclear magnetic resonance methods.
84 citations
TL;DR: In this article, a surface energy analysis is developed for predicting the locus of the MBS particles in the two-phase matrix, combined with knowledge of pair miscibility proved to be a useful predictive method.
TL;DR: In this paper, two and three-component polypropylene (PP) blends and composites were prepared to study their structure/property relationships, and the experimental results indicate a transition to an interpenetrating network (IPN) like structure with increasing elastomer content.
Abstract: Two- and three-component polypropylene (PP) blends and composites were prepared to study their structure/property relationships. Butadiene-styrene (BDS) copolymers of low compatibility formed large particles of poor adhesion in PP resulting in inferior mechanical properties. Better miscibility of ethylene-propylene-diene (EPDM) elastomer results in more finely dispersed particles and the experimental results indicate a transition to an interpenetrating network (IPN)– like structure with increasing elastomer content. Effective impact modification can be achieved only with EPDM elastomers of sufficient miscibility. Mutual wettability and adhesion of the components determine the structure and properties in PP/elastomer/filler systems. Modification of PP by acrylic acid grafting promotes PP/filler adhesion which, in turn, results in the separate dispersion of the components. In an unmodified PP matrix, a significant amount of the filler is encapsulated by the elastomer. At low filler content, better low temperature impact strength is achieved in the case of separately dispersed components, while encapsulation is more advantageous at high filling grades.
TL;DR: In this paper, the authors show that there is an optimum composition of the blends of the lithium sulfonated ionomers (LiSPS) with polyamide-6 (PA-6) at which the simultaneous disruptions of the stiffening effects of crystallinity and of the ''cluster phase» in the blends are at a maximum.
Abstract: Blends [50:50 (w/w)] of polyamide-6 (PA-6) with sulfonated polystyrene ionomers (containing 9.8 mol% of functional groups) show considerable miscibility enhancement (single glass transition at some compositions) when the counterion is Li but are immiscible when the counterion is Na. Dynamic mechanical measurements show that there is an optimum composition of the blends of the lithium sulfonated ionomers (LiSPS) with PA-6 at which the simultaneous disruptions of the stiffening effects of crystallinity and of the «cluster phase» in the blends are at a maximum
TL;DR: In this article, two polymer blend systems were studied: the poly (acrylonitrile) (PAN)-poly (styrene sulfonic acid) (PSSA) and the polyvinyl alcohol (PVA)-PSSA blend.
TL;DR: In this article, a mixture of poly(vinylphenol) with poly(ethylene oxide) (PEO) or poly-ethylene glycol (PEG) blends is studied and the results indicate that an intermolecular hydrogen-bonding interaction causes the blends to be miscible.
Abstract: Blends of poly(vinylphenol) (PVPh) with poly(ethylene oxide) (PEO) or poly(ethylene glycol) (PEG) blends are studied. The results indicate that an intermolecular hydrogen-bonding interaction causes the blends to be miscible. The miscibility and the phase structure of the blends show a significant compositional dependence. When PVPh is rich, the two polymers are miscible and form an amorphous phase homogeneous on the 20-30 A scale as well as the 200-300 A scale. The motion of PEO (PEG) in the miscible phase is restricted by PVPh. At a PEO (PEG) composition of about 50 wt%, the amorphous PEO (PEG) phase appears and coexists with the miscible phase
TL;DR: In this paper, an association model is applied to blends where one component contains secondary alkyl hydroxyl groups, and the model can be applied to the poly(hydroxy ether of Bisphenol A) (Phenoxy).
Abstract: An association model is applied to blends where one component contains secondary alkyl hydroxyl groups. The use of this model requires a knowledge of parameters (equilibrium constants) describing the self-association of the pure component, and the determination of these parameters from infrared studies of model compounds is described. Included is the complication that the self-associating species also contains ether groups, so that the model can be applied to the poly(hydroxy ether of Bisphenol A) (Phenoxy). Phase diagrams and miscibility windows for Phenoxy blends with polyesters and polymethacrylates were calculated
TL;DR: In this article, an endothermic heat of demixing and its concentration and temperature dependences were measured by DSC and extrapolated from these measurements and the results were interpreted in terms of the modified Flory's equation-of-state theory by Hamada et al. and compared with predictions of the directional specific interaction model of ten Brinke and Karasz.
Abstract: Amorphous blends of PMMA and PVC prepared by solution precipitation were found to be miscible over the entire composition range at temperatures below 180°C. An endothermic heat of demixing and its concentration and temperature dependences were measured by DSC. Spinodal and cloud point curves were extrapolated from these measurements and the results were interpreted in terms of the modified Flory's equation-of-state theory by Hamada et al. and compared with predictions of the directional specific interaction model of ten Brinke and Karasz.
TL;DR: The scale of miscibility of the different blends was evaluated from NMR data as mentioned in this paper, ranging from 4 to more than 30 nm. The possible factors affecting the results are discussed.
Abstract: Blend films of cellulose with poly(vinyl alcohol), polyacrylonitrile, poly(e-caprolactone) and nylon 6 were prepared from mixed solutions in DMAc/LiCl by coagulation in a nonsolvent. The scale of miscibility of the different blends was evaluated from NMR data. The values lie in the range from 4 to more than 30 nm. The possible factors affecting the results are discussed.
TL;DR: In this paper, the influence of phase separation on the linear viscoelastic response has been studied in miscible blends of polystyrene and poly(vinyl methyl ether) with a lower critical solution temperature near 110°C.
Abstract: The influence of phase separation on the linear viscoelastic response has been studied in miscible blends of polystyrene and poly(vinyl methyl ether) with a lower critical solution temperature near 110 °C. At temperatures between 25 and 155 °C, and for compositions in the range 20% to 60% polystyrene, the complex moduli G’ and G‘ were measured at frequencies in the range of 0.01 to 100 rad/s. Time–temperature superposition was applied in the single phase region to obtain the complex modulus over eight decades of frequency. Increasing the polystyrene content resulted in an increase in the zero‐shear viscosity and a shift of the terminal behavior to lower frequencies or longer times. The phase separation above the lower critical solution temperature was measured as a sudden increase in the fluorescence intensity of an anthracene‐labeled polystyrene (approximately 1 wt % in the blend), using an optical probe in the rheometer fixture. For the 20/80 and 40/60 PS/PVME samples, the terminal zone was in the acces...
TL;DR: In this paper, the phase separation of an aromatic polyethersulfone and a polyimide mixture was studied by differential scanning calorimetry, dynamic mechanical analysis, and rheological techniques.
Abstract: Blends of an aromatic polyethersulfone (commercial name Victrex) and a polyimide (commercial name Matrimid 5218), the condensation product of 3,3′,4,4′-benzophenone tetracarboxylic dianhydride and 5(6)-amino-1-(4′-aminophenyl)-1,3,3′-trimethylindane, were studied by differential scanning calorimetry, dynamic mechanical analysis, and rheological techniques. The blends appeared to be miscible over the whole range of compositions when cast as films or precipitated from solution in a number of solvents. After annealing above the apparent phase boundary, located above Tg, the blends were irreversibly phase separated indicating that the observed phase boundary does not represent a true state of equilibrium. Only a narrow “processing window” was found for blends containing up to 20 wt % polyimide. Rheological measurements in this range of compositions indicated that blending polyethersulfone with polyimide increases the complex viscosity and the elastic modulus of the blends. For blends containing more than 10 wt % polyimide, abrupt changes in the rheological properties were observed at temperatures above the phase boundary. These changes may be consistent with the formation of a network structure (due to phase separation and/or crosslinking). Blends containing less than 10 wt % polyimide exhibited stable rheological properties after heating at 320°C for 20 min, indicating the existence of thermodynamic equilibrium.
TL;DR: In this paper, the equilibrium phase behavior of binary blends of various polycarbonates (PC) with polystyrene (PS), poly(methyl methacrylate) (PMMA), bisphenol A polycarbonate and tetramethylbisphernol Apolycarbonate is studied.
Abstract: The equilibrium phase behavior of binary blends of various polycarbonates (PC) with polystyrene (PS), poly(methyl methacrylate) (PMMA), bisphenol A polycarbonate and tetramethylbisphernol A polycarbonate is studied. The variations in PC structure primarily involved substitutions onto the phenyl rings, or both, of the bisphenol monomer. Polar connector groups promote favorable interactions with PMMA while ring substitution with methyl groups improves miscibility with PS. Other structural changes in the connector group or on the phenyl rings can act against the miscibility of PC with PMMA or PS
TL;DR: In this paper, the authors show that the average interaggregate spacing is roughly the same in ZnSPS and its 50/50 blend with poly(2,6-dimethyl-1,4-phenylene oxide) at a given sulfonation level.
Abstract: Zinc-neutralized sulfonated polystyrene ionomers (ZnSPS) and poly(2,6-dimethyl-1,4-phenylene oxide) (PXE) form miscible blends up to at least 7.8 mol% sulfonation as measured by thermal and mechanical criteria. The addition of an equal weight of PXE raises the T g of ZnSPS by 40-50°C. However, this miscibility is not achieved by eradicating the microdomain structure present in ZnSPS. SAXS indicates that while the average interaggregate spacing is roughly the same in ZnSPS and its 50/50 blend with PXE at a given sulfonation level; hte extent of phase separation is reduced upon PXE addition
TL;DR: In this article, a new concept is presented based upon the utilization of the individual component contributions to the solubility parameter, which describes the interaction of polymer repeat units, provides semi-quantitative values which relate the three basic interactive forces, i.e. dispersive, polar and hydrogen bonding.
TL;DR: In this article, the critical stress intensity factor (K 1c ) and critical strain energy release rate (G 1c ), the morphology and glass transition temperatures were examined by a three-point bending test, scanning and transmission electron microscopy and by dynamic mechanical analysis, respectively.
TL;DR: In this article, the presence of three phases between SmA and the antiferroelectric SmCA* phase in optically active (R)-4-(1-methylheptyloxycarbonyl)phenyl 4'-octylbiphenyl-4-carboxylate was found.
Abstract: The presence of three phases was found between SmA and the antiferroelectric SmCA* phase in optically active (R)-4-(1-methylheptyloxycarbonyl)phenyl 4'-octylbiphenyl-4-carboxylate. Two of these phases were identified as SmCα* and SmCγ* by the miscibility test. The remaining phase between these was confirmed to be another antiferroelectric phase from dielectric measurement and conoscopic observation. Thus, antiferroelectric order appears at least three times: SmCα*, the new antiferroelectric phase and SmCA*. The new antiferroelectric phase is different from the SmCA* phase in that it exhibits much lower stability against an electric field.
TL;DR: In this article, the Flory-Huggins interaction parameter calculated by using these data assumes values about 0.035 ± 0.010, which is very close to values foreseen by the rule of mixtures.
Abstract: Dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) concurrently show that polycarbonate (PC)/poly(methyl methacrylate) (PMMA) blends have a two-phase structure. The differences between the Tgs of parent polymers and the Tgs of conjugate phases, determined by both DMTA and DSC, indicate a limited miscibility of components and allow the approximate composition of conjugate phases to be calculated. The Flory-Huggins interaction parameter calculated by using these data assumes values about 0.035 ± 0.010. Phase inversion occurs in an interval close to the 50/50 composition, though the molar masses and melt viscosities of the polymers were rather different. Partial miscibility of components ensures interfacial adhesion capable of sustaining the stress transfer between phases up to fracture. Yield stress of the blends is very close to values foreseen by the rule of mixtures. A specific feature of the blends studied is that the addition of 10 to 20 vol% of PMMA to PC increases the strain at break and work to fracture, which are rather low for the PC used. The enhanced capability of the blends to absorb mechanical energy is probably linked to plastic deformation of the dispersed PMMA.
TL;DR: In this paper, the authors derived dimensionless equilibrium constants describing the selfassociation of the hexafluoro-2-phenyl-2propanol (HFPP) group from IR spectroscopic data.
Abstract: Dimensionless equilibrium constants describing the self-association of the hexafluoro-2-phenyl-2-propanol (HFPP) group have been determined from IR spectroscopic data. Corresponding values of these equilibrium constants for polymers containing the p-(hexafluoro-2-hydroxy-2-propyl)styrene (HFPS) group were calculated by taking into account differences in the molar volume of the model and what we define as the «specific repeat» of the polymer. Equilibrium constants describing the interassociation of HFPS with methacrylate and acetoxy groups were obtained from spectroscopic data
TL;DR: In this paper, a triple-resonance 1H,19F,13C solid-state CPMAS NMR was used to examine the miscibility of isotactic, syndiotactic, or atactic PMMA with poly(vinylidene fluoride) (I).
Abstract: Triple-resonance 1H,19F,13C solid-state CPMAS NMR was used to examine the miscibility of isotactic, syndiotactic, or atactic PMMA with poly(vinylidene fluoride) (I). From the fluorine-to-carbon cross-polarization expts., the av. distance between F and OCH3 carbons in intimately mixed I and PMMA was estd. Exptl. evidence for a specific interaction between I and PMMA segments was presented. The proton-to-fluorine cross-depolarization expts. yielded information on size and compn. of the mixed PMMA/I phase. The fraction of nonmixed PMMA was detd. for these blends, and this fraction was smaller for isotactic than for atactic and syndiotactic PMMA. Large differences in the amts. of isolated PMMA were obsd. between melt-mixed and copptd. blends.
TL;DR: In this article, the phase behavior of binary blends of copolycarbonates of tetramethyl bisphenol-A and bisphensol-a (TMPC-PC) with copolymers of styrene with acrylonitrile (SAN) or styrenewith methyl methacrylate (SMMA) has been examined as a function of composition of each copolymer.
TL;DR: The morphology of blends of styrenic polymers in a matrix of 75% Nylon-6 prepared in a Brabender Plasti-Corder was examined by scanning electron microscopy.
Abstract: The morphology of blends of styrenic polymers in a matrix of 75% Nylon-6 prepared in a Brabender Plasti-Corder was examined by scanning electron microscopy. Styrene/acrylonitrile copolymers (SAN) form smaller particles as the AN level increases owing to the corresponding decrease in the SAN–polyamide interfacial tension. Various styrenic polymers containing functional groups, maleic anhydride or oxazoline type, that can react with Nylon-6 during melt processing were added to the SAN phase which also led to a decrease in the particle size owing to the graft copolymer formed in situ. The effects of functional group type, amount of functional groups per chain, amount of functional polymer added, and the miscibility of the styrene/maleic anhydride (SMA) and SAN copolymers on the morphology of the styrenic phase in the Nylon-6 matrix are described. © 1992 John Wiley & Sons, Inc.