Miscibility Of Poly Research Articles

Thermally driven collapse of a polymer brush in a polymer matrix

The segment density profile of end-functionalized deuterated polystyrene $(d\ensuremath{-}\mathrm{PS})$ brush in a miscible poly(vinyl methyl ether) (PVME) polymer matrix was studied using neutron reflectivity. Brushes were chemically anchored to a silicon substrate. PVME has a favorable interaction with PS at room temperature. As the temperature increases, the interaction between PS and PVME becomes more unfavorable until in the bulk phase separation would occur. From the reflectivity experiments, it was found that the PVME was expelled from the brush as the temperature was increased. This process was reversible for temperatures up to $90\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$; above this the volume fraction in the brush approached unity and macroscopic dewetting occurred. The height of the brush was sufficiently well predicted by a scaling theory, which predicts a cube root dependence on the Flory-Huggins interaction parameter.

Miscibility and interpolymer complexation of poly(1-vinyl-imidazole) with hydroxyl- and carboxyl-containing polymers

The miscibility of poly(1-vinylimidazole) (PVI) with some hydroxyl- and carboxyl-containing polymers was studied. Each of the binary blends or complexes of PVI with poly(p-vinylphenol) (PVPh), poly(2-hydroxypropyl methacrylate) (PHPMA) and poly(acrylic acid) (PAA) showed a single glass transition temperature (T g ), indicating miscibility. However, PVI is immiscible with poly(styrene-co-allyl alcohol) (SAA) and poly(hydroxyether of bisphenol-A) (Phenoxy) as shown by the appearance of two T g 's in each of the blends. Based on the frequency shifts of the hydroxyl band of the hydroxyl-containing polymers, the intensities of hydrogen bonding interactions between PVI and hydroxyl-containing polymers are in the order PVPh > PHPMA > SAA and Phenoxy. PVI interacts with PAA via ionic interaction.

Miscibility of poly(epichlorohydrin)/poly( N-vinyl-2-pyrrolidone) blends investigated with high-resolution solid-state 13C n.m.r.

The miscibility of poly(epichlorohydrin)/poly( N-vinyl-2-pyrrolidone) (PECH/PVP) blends was investigated by 13C cross-polarization combined with magic-angle sample spinning and high-power dipolar decoupling (CP/MAS/DD) techniques. Intermolecular cross-polarization and the downfield shifting of the carbonyl resonance of PVP indicate intermolecular hydrogen bonding. 1H T 1ρ relaxation rates monitored at the carbonyl group in PECH/PVP blends were found as the weighted averages between the T 1ρ relaxation rate of the carbonyl group in pure PVP and that of the mobile α-hydrogen in pure PECH. A 1.3 ppm downfield shift was found for the carbonyl carbon of PVP in the 13C CP/MAS/DD spectra. These observations provide evidence of strong hydrogen-bonding interactions between the carbonyl group and the α-hydrogen. The polymer components are completely miscible at the molecular level at all compositions. In addition, the methine β-C of PECH is split into two peaks at 80.0 and 76.2 ppm and the methylene γ-C is also split into two peaks at 70.6 and 66.0 ppm. The upfield shifts of the methine and methylene peaks are due to strong dipolar interactions resulting in higher shielding of the 13C nuclei.

Miscibility and phase behavior of poly(D,L-lactide)/poly(p-vinylphenol) blends

The miscibility of poly(D,L-lactide) (PDLLA) and poly(p-vinylphenol) (PVPh) blends has been studied by differential scanning calorimetry and Fourier transform infrared spectroscopy (FTIR). Phase separation was observed in blends over a wide composition range. A PDLLA-rich phase was found to coexist with an almost pure PVPh phase. The quenched blend samples showed two glass transitions (Tgs), except for a blend with a low PVPh content. However, the Tg value of the PDLLA-rich phase showed a gradual increase with increasing PVPh content. No evidence of interassociation (hydrogen bond formation) between PDLLA and PVPh was found by FTIR. The phase behavior of the blends was simulated using an association model. The results suggested that the equilibrium constant of interassociation between PDLLA and PVPh was small. The phase compositions of the two separated phases were calculated using Fox, Gordon-Taylor, and Couchman equations. The amount of PVPh in the PDLLA-rich phase increased with increasing PVPh content in the blend. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 811–816, 1998

Reversibility of thermodynamic lower critical solution temperature phenomenon in miscible poly(ε-caprolactone)/poly(benzyl methacrylate)

Differential scanning calorimetry and optical microscopy were performed to examine the reversibility of phase separation at above the lower critical solution temperatures in a miscible poly(e-caprolactone) (PCL)/poly(benzyl methacrylate) (PBzMA) blend system. Upon heating, phase separation occurred via a binodal nucleation and growth (NG) mechanism at above 240 °C, which is a lower critical solution temperature (LCST). The pattern of phase domains suggests that the phase separation was meta-stable. Interestingly, the LCST phase separation was found to be readily reversible to original homogeneity upon cooling at regularly accessible rates. A major factor may be that the temperature window between the LCST curve and blend Tg curve is wide, resulting in a convenient temperature range for the polymer chains to kinetically reorganize to a state favored by the thermodynamic conditions.

Examination of miscibility at molecular level of poly(hydroxyether of bisphenol A)/poly(N-vinyl pyrrolidone) blends by cross-polarization/magic angle spinning13C nuclear magnetic resonance spectroscopy

The miscibility of poly(hydroxyether of bisphenol A) (phenoxy) and poly(N-vinyl pyrrolidone) (PVP) was investigated by differential scanning calorimetry (DSC) and high-resolution solid-state nuclear magnetic resonance (NMR) techniques. The DSC studies showed that the phenoxy/PVP blends have a single, composition-dependent glass transition temperature (Tg). The S-shaped Tg-composition curve of the phenoxy/PVP blends was reported, which is indicative of the strong intermolecular hydrogen-bonding interactions. To examine the miscibility of the system at molecular level, high-resolution solid-state 13C nuclear magnetic resonance (NMR) technique was employed. Upon adding phenoxy to system, the chemical shift of carbonyl carbon resonance of PVP was observed to shift downfield by 1.6 ppm in the 13C cross-polarization (CP)/magic angle spinning (MAS) together with the high-power dipolar decoupling (DD) spectra when the concentration of phenoxy is 90 wt %. The observation was responsible for the formation of intermolecular hydrogen bonding. The proton spin-lattice relaxation time T1(H) and the proton spin-lattice relaxation time in the rotating frame T1ρ(H) were measured as a function of the blend composition. The T1(H) result was in good agreement with the thermal analysis, i.e., the blends are completely homogeneous on the scale of 20 ∼ 30 nm. The six results of T1ρ(H) further indicated that the blends were homogeneous on the scale of 40 ∼ 50Å. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. B Polym. Phys. 36: 2291–2300, 1998

Miscibility and crystallization behaviour of poly( l-lactide)/poly( p-vinylphenol) blends

The miscibility of poly( l-lactide) (PLLA)/poly( p-vinylphenol) (PVPh) blends has been studied by differential scanning calorimetry (d.s.c.) and Fourier transform infrared ( FTi.r.) spectroscopy. PLLA/PVPh blends are partially miscible as characterized by shifts in the glass transition temperatures ( T gs) of the two component polymers. The T g of the PLLA-rich phase increases with increasing PVPh content, while that of the PVPh-rich phase decreases with increasing PLLA content. The apparent melting temperature of PLLA is significantly depressed with increasing PVPh content. Weak hydrogen-bonding interaction exists between the carbonyl groups of PLLA and the hydroxyl groups of PVPh as evidenced in the FTi.r. spectra. In the amorphous state, the hydrogen-bonded hydroxyl band of PVPh shifts to a higher frequency upon blending with PLLA, while the carbonyl stretching band of PLLA shifts to a lower frequency with the addition of PVPh. In addition, a new carbonyl stretching band attributed to the hydrogen-bonded carbonyl groups of PLLA is found at 1700 cm −1. The crystallinity of PLLA in the blends displays a marked decrease with increasing PVPh content. When the PVPh content is above 40 wt%, crystallization of PLLA does not occur under isothermal conditions. Moreover, the cold crystallization process of the PLLA component is also affected significantly by the addition of PVPh.

Miscibility behaviour in blends of copolymers of vinyl alcohol with poly(ethyloxazoline)

Miscibility of poly(ethyloxazoline) (PEOX) with poly(ethylene-co-vinyl alcohol) (EVAL copolymers) containing 78, 68, 56 and 25 mol-% of vinyl alcohol units has been investigated and compared with the results obtained for the mixtures of PEOX with poly(vinyl acetate-co-vinyl alcohol) (ACAL copolymers). Differential Scanning Calorimetry (DSC) results indicate that PEOX is immiscible with EVAL25. The miscibility behaviour of the blends of EVAL78, EVAL68 and EVAL56 with PEOX was determined by dilute solution viscometry; the results show that EVAL78 and EVAL68 are miscible with the tertiary polyamide PEOX for all compositions. EVAL56/PEOX blends are immiscible in certain compositions. Infrared spectroscopy studies of miscible and immiscible blends reveal the existence of specific interactions via hydrogen bonding between the hydroxyl groups in vinyl alcohol units of the copolymers and the carbonyl group in the tertiary amide. According to these results, infrared spectroscopy is not apt to reveal miscibility within the system studied.

Miscibility behaviour in blends of copolymers of vinyl alcohol with poly(ethyloxazoline)

Miscibility of poly(ethyloxazoline) (PEOX) with poly(ethylene-co-vinyl alcohol) (EVAL copolymers) containing 78, 68, 56 and 25 mol-% of vinyl alcohol units has been investigated and compared with the results obtained for the mixtures of PEOX with poly(vinyl acetate-co-vinyl alcohol) (ACAL copolymers). Differential Scanning Calorimetry (DSC) results indicate that PEOX is immiscible with EVAL25. The miscibility behaviour of the blends of EVAL78, EVAL68 and EVAL56 with PEOX was determined by dilute solution viscometry; the results show that EVAL78 and EVAL68 are miscible with the tertiary polyamide PEOX for all compositions. EVAL56/PEOX blends are immiscible in certain compositions. Infrared spectroscopy studies of miscible and immiscible blends reveal the existence of specific interactions via hydrogen bonding between the hydroxyl groups in vinyl alcohol units of the copolymers and the carbonyl group in the tertiary amide. According to these results, infrared spectroscopy is not apt to reveal miscibility within the system studied.

Behaviour of the miscibility of poly(ethylene oxide)/liquid crystal blends

The microscopic behaviour of blends of poly(ethylene oxide) with two different low molecular weight liquid crystals (LC) was studied in order to evaluate miscibility. One of the liquid crystal components had a phase transition temperature lower than the melting temperature of poly(ethylene oxide) (PEO), and the other a higher value. The low molecular weight liquid crystal components were 4-cyano-4′-n-heptylbiphenyl (7CB) and p-cyanophenyl p-pentyloxybenzoate (pCP). Thermal analysis and polarized optical and scanning electron microscopy were employed. The melting temperature (Tm) depression of PEO increased with LC content in the blend, suggesting that the PEO was miscible with both liquid crystals in the isotropic phase. The spherulitic structural morphology of the semicrystalline components is affected by the presence of liquid crystals. © 1998 SCI.

Miscibility in blends of poly(vinyl acetate-co-vinyl alcohol) with poly(N,N-dimethylacrylamide)

Miscibility of poly(N,N-dimethylacrylamide) (PDMA) with poly(vinyl acetate) (PVAC), poly(vinyl alcohol) (PVAL) and poly(vinyl acetate co-vinyl alcohol) (ACAL copolymers) has been investigated over a wide composition range. Differential scanning calorimetry (DSC) results indicate that PDMA is immiscible with PVAC, but is miscible with PVAL and ACAL copolymers in certain range of compositions. The ACAL/PDMA phase diagram for different copolymer compositions has been determined. The variation of the glass transition temperature with blend composition for miscible systems was found to follow the Kwei equation. Infrared spectroscopy studies of blends reveal the existence of specific interactions via hydrogen bonding between hydroxyl groups in vinyl alcohol units and the carbonyl group in the tertiary amide, which appear to be decisive for miscibility.

Melting behavior, miscibility, and hydrogen-bonded interactions of poly(?-caprolactone)/poly(4-hydroxystyrene-co-methoxystyrene) blends

The miscibility of poly(4-hydroxystyrene-co-methoxystyrene) (HSMS) and poly(ε-caprolactone) (PCL) was investigated by differential scanning calorimetry and Fourier transform infrared spectroscopy (FTIR). HSMS/PCL blends were found to be miscible in the whole composition range by detecting only a glass transition temperature (Tg), for each composition, which could be closely described by the Fox rule. The crystallinity of PCL in the blends was dependent on the Tg of the amorphous phase. The greater the HSMS content in the blends, the lower the crystallinity. The polymer–polymer interaction parameter, χ32, was calculated from melting point depression of PCL using the Nishi-Wang equation. The negative value of χ32 obtained for HSMS/PCL blends has been compared with the value of χ32 for poly(4-hydroxystyrene) (P4HS)/PCL blends. The specific nature, quantitative analysis, and average strength of the intermolecular interactions in HSMS/PCL and P4HS/PCL blends have been determined at room temperature and in the molten state by means of Fourier transform infrared spectroscopy (FTIR) measurements. The FTIR results have been in good correlation with the thermal behavior of the blends. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 95–104, 1998

Compatibility of poly(3-hydroxybutyrate)/poly(ethylene- co-vinyl acetate) blends

The miscibility of poly(3-hydroxybutyrate) (PHB) with ethylene-vinyl acetate (EVA) copolymers containing 70 or 85 wt% of vinyl acetate was investigated. The blend of PHB and EVA70 was found to be immiscible, because the glass transition temperature, the melting temperature and the spherulite growth rate under the isothermal crystallization conditions were independent of the blend composition. However, the melting temperature, the spherulite growth rate and the equilibrium melting temperature of the PHB/EVA85 blend decreased with an increase in the EVA85 content and the Flory-Huggins interaction parameter of the blend was negative. Therefore, PHB was found to be miscible with EVA85.

Poly(vinyl chloride) as a common solvent for enhancing the miscibility of poly(ethylene-co-vinyl acetate)--poly(styrene-co-acrylonitrile) blends

Poly(vinyl chloride) as a common solvent for enhancing the miscibility of poly(ethylene-co-vinyl acetate)--poly(styrene-co-acrylonitrile) blends

Studies on miscibility of poly(phenylene oxide)‐based ionomer/polystyrene‐based ionomer blends

The phase behavior of a series of blends obtained from mixing carboxylated poly(phenylene oxide) with sulfonated polystyrene and their respective neutralized ionomers was studied by differential scanning calorimetry. A substantially broader range of miscibility was observed when both blend components were functionalized, compared with blends in which only one of the components contained an acid group or was an ionomer. The properties of metallic cations which were used to neutralize the acid groups in the blends were found to have an effect on the miscibility. The miscibility of the two acid polymers or their ionomers depended on the difference of their functionalization level instead of on the absolute percentage of functional groups on each polymer. It was found that the two acid polymers or their ionomers remained miscible as long as they had a similar percentage of functional groups. © 1997 John Wiley & Sons, Inc. J Appl Polm Sci 65:341–346, 1997

Studies on miscibility of poly(phenylene oxide)-based ionomer/polystyrene-based ionomer blends

The phase behavior of a series of blends obtained from mixing carboxylated poly(phenylene oxide) with sulfonated polystyrene and their respective neutralized ionomers was studied by differential scanning calorimetry. A substantially broader range of miscibility was observed when both blend components were functionalized, compared with blends in which only one of the components contained an acid group or was an ionomer. The properties of metallic cations which were used to neutralize the acid groups in the blends were found to have an effect on the miscibility. The miscibility of the two acid polymers or their ionomers depended on the difference of their functionalization level instead of on the absolute percentage of functional groups on each polymer. It was found that the two acid polymers or their ionomers remained miscible as long as they had a similar percentage of functional groups. © 1997 John Wiley & Sons, Inc. J Appl Polm Sci 65:341–346, 1997

BLENDS OF POLY(ISOBUTYL METHACRYLATE-CO-ACRYLIC ACID) WITH POLY{STYRENE-CO-[2-(N,N-DIMETHYL AMINO)ETHYL METHACRYLATE]} OR POLY(STYRENE-CO-4-VINYLPYRIDINE)

The miscibility of poly(isobutyl methacrylate-co-acrylic acid) (IBMAA) with poly{styrene-co-[2-(N,N-dimethyl amino) ethyl methacrylate]} (SDAEM) or poly(styrene-co-4-vinylpyridine) (S4VP) was studied by differential scanning calorimetry and inverse gas chromatography. IBMAA containing 10 mol% of acrylic acid was found to be immiscible in all proportions with not only SDAEM containing 6 mol% of [2-(N,N-dimethyl amino) ethyl methacrylate] but also with (S4VP) containing 15 or 22 mol% of 4-vinylpyridine.However, as a result of a higher level of specific favorable interactions between moieties in the copolymers, the same isobutyl methacrylate copolymer (IBMAA-10) or copolymer of higher content of acrylic acid are miscible with SDAEM copolymer containing 12 mol% of the basic comonomer, as evidenced from the single glass transition temperature-composition determined by both techniques and the negative values of the apparent polymer-polymer interaction parameters. An attempt at interpretation of the miscibility of IBMAA-10/SDAEM-12 blends was carried out from the interaction energy densities and the solubility parameters of these copolymers and of their blends. Miscible blends of IBMAA-22 and S4VP-15 were also observed. © 1997 Elsevier Science Ltd

Polypeptide‐synthetic polymer hybrids, 1. Miscibility of poly(vinyl alcohol) with poly(sodium α,β‐D,L‐aspartate)

AbstractThe present paper describes materials of polypeptide‐commodity polymer hybrids from poly(vinyl alcohol) (PVA) and poly(sodium α,β‐D,L‐aspartate) (1). Miscible blend films of polypeptide 1 and PVA were prepared by the solvent‐cast method from a homogeneous aqueous solution. Differential scanning calorimetry. Fourier transform infrared, and scanning electron microscopy combined with energy dispersive X‐ray spectroscopy (EDX) were used to investigate the blends. It was revealed that 1 and PVA are miscible in a wide range of compositions.

Properties of the polyethylene/poly (2,6-dimethyl-1,4-phenylene ether)/polystyrene system in the presence of SEPS block copolymers

An immiscible polymer system of polyethylene (HDPE)/poly(2,6-dimethyl-1,4-phenylene ether)/polystyrene was compatibilized in the presence of a specific formulated compatibilizer and the properties of this system were studied, in particular, as a function of the poly(phenylene ether) and polystyrene content in the blend with polyethylene and as a function of compatibilizer concentration. The compatibilizer used was a hydrogenated styrene/isoprene/styrene triblock copolymer (SEPS) which also contained quantities of polypropylene and paraffin oil. Selected thermal, mechanical, and processing properties were investigated and their special features are discussed. In relation to specific properties like the modulus of elasticity and notched Izod impact strength, the polymer system with a hydrogenated SEPS triblock copolymer investigated seems to be a better compatibilized system than other blends described. The phase behavior of the polymer system was characterized using DSC and showed three general polymer phases: a partially crystalline polyethylene phase, an amorphous mixed phase of miscible poly(phenylene ether) and polystyrene, as well as a preferred isotactic crystalline polypropylene phase. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1835–1842, 1997

The influence of stereoregularity on the miscibility of poly(propylene)s

The melt miscibility of atactic poly(propylene) (a-PP) with isotactic (i-PP) and syndiotactic poly(propylene) (s-PP), respectively, is investigated by diffusion experiments of i-PP/a-PP/i-PP or s-PP/a-PP/s-PP sandwich specimens using polarized light microscopy. It is shown that the system a-PP/i-PP is miscible in the melt, whereas for the system a-PP/s-PP no evidence for melt mixing is found. Pressure-volume-temperature (PVT) measurements of the three poly(propylene)s are carried out in order to determine the characteristic parameters of the Flory-Orwoll-Vrij equation-of-state theory. Theoretical predictions using the solubility parameter concept are in agreement with the observed miscibility behavior of the blends. Differences in the cohesive energy densities of a-PP and i-PP on the one side, and s-PP on the other side, are found to be responsible for the phase behavior of the mixtures of poly(propylene)s with different stereoregularity. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 1135–1144, 1997