Phase behavior of ternary blends containing dimethylpolycarbonate,tetramethylpolycarbonate and poly[styrene‐co‐(methyl methacrylate)] copolymers (or polystyrene)

The miscibility and phase behavior of ternary blends containing dimethylpolycarbonate (DMPC), tetramethylpolycarbonate (TMPC) and poly[styrene‐co‐(methyl methacrylate)] copolymer (SMMA) have been explored. Ternary blends containing polystyrene (PS) instead of SMMA were also examined. Blends of DMPC with SMMA copolymers (or PS) did not form miscible blends regardless of methyl methacrylate (MMA) content in copolymers. However, DMPC blends with SMMA (or PS) blends become miscible by adding TMPC. The miscible region of ternary blends is compared with the previously determined miscibility region of binary blends having the same chemical components and compositions. The region where the ternary blends are miscible is much narrower than that of binary blends. Based on lattice fluid theory, the observed phase behavior of ternary blends was analyzed. Even though the term representing the Gibbs free energy change of mixing for certain ternary blends had a negative value, blends were immiscible. It was revealed that a negative value of the Gibbs free energy change of mixing was not a sufficient condition for miscible ternary blends because of the asymmetry in the binary interactions involved in ternary blends. Copyright © 2004 Society of Chemical Industry     

PMMA‐modified divinylester/styrene resins: Phase diagrams and morphologies

Binary and ternary experimental cloud‐point curves (CPCs) for systems formulated with a low molar mass synthesized divinylester (DVE) resin, styrene (St), and poly(methyl methacrylate) (PMMA) were determined. The CPCs results were analyzed with the Flory–Huggins (F‐H) thermodynamic model taking into account the polydispersity of the DVE and PMMA components, to calculate the different binary interaction parameters and their temperature dependences. The St‐DVE system is miscible in all the composition range and down to the crystallization temperature of the St; therefore, the interaction parameter expression reported for a higher molar mass DVE was adapted. The interaction parameters obtained were used to calculate the phase diagrams of the St‐PMMA and the DVE‐PMMA binary systems and that of the St‐DVE‐PMMA ternary system at three different temperatures. Quasiternary phase diagrams show liquid–liquid partial miscibility of the St‐PMMA and DVE‐PMMA pairs. At room temperature, the St‐DVE‐PMMA system is miscible at all compositions. Final morphologies of PMMA‐modified cured St‐DVE materials were generated by polymerization‐induced phase separation (PIPS) mechanism from initial homogeneous mixtures. SEM and TEM micrographs were obtained to analyze the generated final morphologies, which showed a direct correlation with the initial miscibility of the system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4539–4549, 2006     

Study of the solvent effect on miscibility between poly(vinyl chloride) and poly(methyl methacrylate) in the solution state – viscometric measurements

In this work, the solvent effect on the miscibility between poly(vinyl chloride) (PVC) and poly(methyl methacrylate) (PMMA) in ternary polymer solutions was examined by the viscometric method. In these systems, we could understand that the used solvents, tetrahydrofuran (THF) or N,N‐dimethylformamide (DMF), mainly affect the interaction between PVC and PMMA, while prompting various miscible properties. In PVC/PMMA/THF solution, THF is a near θ‐solvent and a poor solvent for PVC and PMMA, respectively. The mixing of the tighter PMMA coils and more extended PVC coils in THF may cause the sea–island heterogeneous structure below the weight fraction of PMMA in the polymer mixture w_PMMA = 0.7, resulting in immiscible PVC/PMMA mixtures. At w_PMMA ≥ 0.7, the PVC/PMMA mixtures are relatively miscible, giving homogeneous polymer solutions. It means that the miscibility between PVC and PMMA depends on the composition of polymer mixture. However, due to the similar affinity of DMF to PVC and PMMA, PVC/PMMA/DMF solutions exhibit high miscibility between PVC and PMMA at about w_PMMA = 0.5. © 2000 Society of Chemical Industry     

Achieving miscible ternary polymer blends with hydrogen bonding

Poly(vinyl phenol) (PVPh) has previously been found to be successful in making immiscible poly(methyl methacrylate) (PMMA)/poly(vinyl acetate) (PVAc) miscible. Poly(ethyl methacrylate) (PEMA) with one more methyl group than PMMA is also immiscible with PVAc. PEMA and PVAc are miscible with PVPh according to the literature. To determine whether PVPh can also cosolubilize PEMA/PVAc, PVPh samples of two different molecular weights have been mixed in this study with PEMA and PVAc to produce a ternary blend. On the basis of the calorimetry data, the ternary PEMA/PVAc/PVPh blend, regardless of the molecular weight of PVPh, has been determined to be miscible. The reason for the observed miscibility is probably that the interactions between PVAc and PVPh are similar in magnitude to those between PEMA and PVPh. A modified Kwei equation based on the binary interaction parameters proposed previously is used to describe the experimental glass‐transition temperature of the miscible ternary blend almost quantitatively well. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 643–652, 2006     

Phase behavior of hydrogen‐bonded ternary polymer blends

Although poly(ethyl methacrylate) (PEMA) and poly(methyl methacrylate) (PMMA) are only slightly different in structure, they are known to be immiscible. Polystyrene is not miscible with PEMA or PMMA. However, when polystyrene is modified to contain certain vinyl phenol groups to become poly(styrene‐co‐vinyl phenol) (PSVPh), it can be miscible with both PEMA and PMMA. What is the miscibility of a ternary blend consisting of PEMA, PMMA, and PSVPh? For this question to be answered, binary blends of PEMA (or PMMA) were first made with PSVPh. Their miscibility was examined. Then, ternary blends composed of PEMA, PMMA, and PSVPh were prepared and measured calorimetrically. The role of PSVPh between PEMA and PMMA and the effect of different contents of vinyl phenol groups on the miscibility of the ternary blends were investigated. On the basis of experimental results, increasing the vinyl phenol contents of PSVPh seemed to have an adverse effect on the miscibility of the ternary blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2088–2094, 2003     

Further evidence for the effects of critical concentration fluctuations on the diffusion-controlled reaction kinetics in binary polymer mixtures

Summary Kinetics of the intramolecular photodimerization reaction of a molecular probe, 9-(hydroxymethyl)-10-[(Naphthylmethoxy)-methyl] anthracene (HNMA) was studied in the miscible region of binary polymer mixtures. Poly(ethylene oxide)/poly(methyl methacrylate)(PEO/PMMA), polystyrene/poly(vinyl methyl ether) (PSH/PVME) and deuterated polystyrene/poly(vinyl methyl ether) (PSD/PVME) mixtures were used as binary polymer blends. It was found that the reaction kinetics is strongly affected by the concentration fluctuations in the vicinity of the coexistence curve. These behavior are consistent with the magnitude of the binary interaction parameters X estimated from the small-angle neutron-scattering and the melting point depression data. These experimental results confirm the fact that the reaction kinetics of HNMA reflects the concentration fluctuations with the wavelength comparable to the dimension of the probe.     

Miscibility of poly(vinylidene fluoride) and potassium salt of poly(methyl methacrylate-ran-methacrylic acid)

The crystalline–amorphous polymer pair of poly(vinylidene fluoride) and poly(methyl methacrylate) is known to be miscible over a wide composition range. The effects of ionic moieties on the miscibility were studied by replacing the poly(methyl methacrylate) with a series of random copolymers of methyl methacrylate and potassium salt of methacrylic acid. The interaction parameter (χ) for the miscible blends in their molten state was obtained by thermal analysis using a melting-point depression calculation. The parameter decreased to a minimum at c.2% ion content (χ=minus;0.514) and approached a positive value at above 10% ion concentration.     

Influence of the tacticity of poly(methyl methacrylate) on the miscibility with poly(vinyl chloride)

It can be concluded from the work of Schurer et al.¹⁰ that poly(vinyl chloride) (PVC) is more miscible with syndiotactic than with isotactic poly(methyl methacrylate) (PMMA). By choosing different molar masses for the various tactic forms of PMMA it is possible to obtain blends with PVC with similar phase behaviour, i.e. in all cases a cloud-point curve with a minimum in the vicinity of 190°C. In this way a more quantitative statement about the influence of the tacticity of PMMA on its miscibility with PVC can be made. One of the principal differences between syndiotactic or atactic PMMA and isotactic PMMA is the higher flexibility of the latter. Using Flory's equation of state theory it will be shown that the effect of this difference is large enough to explain the difference in phase behaviour observed. Heats of mixing of low molar mass analogues were also measured and found to be negative.     

Miscibility in blends of linear and branched poly(ethylene oxide) with methacrylate derivative random copolymers and estimation of segmental χ parameters

Miscibility in the blends of poly(ethylene oxide) (PEO) with n-hexyl methacrylate-methyl methacrylate random copolymers (HMA-MMA) and 2-ethylhexyl methacrylate-MMA random copolymers (EHMA-MMA) was evaluated using glass transition and light scattering methods. EHMA-MMA was more miscible with PEO than HMA-MMA. Both blends of PEO with HMA-MMA and EHMA-MMA showed UCST-type miscibility although homopolymer blends PEO/PMMA were predicted to be of LCST-type. This was attributed to an increase in the exchange enthalpy with increasing HMA or EHMA composition in the random copolymer. From the copolymer composition dependence of miscibility the segmental χ parameters of HMA/MMA, EHMA/MMA, EO/HMA and EO/EHMA were estimated using the Flory-Huggins theory extended to random copolymer systems. Miscibility in the blends of branched PEO with HMA-MMA whose HMA copolymer composition was 0.16 was compared with that in the linear PEO blends. The former blends were more miscible with HMA-MMA than the latter one by about 35 °C at the maximum cloud point temperature.     

Miscibility of copolycarbonate blends with poly(styrene-co-acrylonitrile) copolymer and their interaction energies

The phase behavior of dimethyl polycarbonate-tetramethyl polycarbonate (DMPC-TMPC) blends with poly(styrene-co-acrylonitrile) copolymers (SAN) and the interaction energies of binary pairs involved in blend has been explored. DMPC-TMPC copolycarbonates containing 60 wt% TMPC or more were formed miscible blends with SAN containing limited amounts of AN. The miscibility of copolycarbonate with SAN decreases as the DMPC content increases. The miscible blends showed the LCST-type phase behavior or did not phase separate until thermal degradation. The binary interaction energies involved in the miscible blends were calculated from the phase boundaries using the lattice-fluid theory combined with binary interaction model. The phenyl ring substitution with methyl groups did not lead to interactions that are favorable for miscibility with polyacrylonitrile (PAN). The interaction energies of the polycarbonates blends with SAN copolymers as a function of AN content were obtained. It was revealed that the incline of the number of methyl groups on the phenyl rings of bisphenol-A unit acts favorably for the miscibility with SAN copolymer when SAN contains less than about 30 wt% AN and shifts the most favorable interaction to the low AN content.     

Miscibility of poly(methoxymethyl methacrylate) and poly(methylthiomethyl methacrylate) with poly(methyl methacrylate)

Summary Poly(n-propyl methacrylate) is known to be immiscible with poly(methyl methacrylate) (PMMA). However, we have found that poly(methoxymethyl methacrylate) is miscible with PMMA, indicating the importance of ether oxygen atoms in achieving miscibility. On the other hand, poly(methylthiomethyl methacrylate) is immiscible with PMMA.     

Miscibility of poly(2-chloroethyl methacrylate) with various polymethacrylates

The miscibility behavior of poly(2-chloroethyl methacrylate) (PCEMA) with various polymethacrylates was investigated by differential scanning calorimetry. PCEMA is miscible with poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), and poly(tetrahydrofurfuryl methacrylate) (PTHFMA), but is immiscible with poly(n-propyl methacrylate), poly(isopropyl methacrylate), poly(n-butyl methacrylate), and poly(cyclohexyl methacrylate). PCEMA/PEMA blends showed lower critical solution temperature (LCST) behavior but PCEMA/PMMA and PCEMA/PTHFMA blends degraded before phase separation could be induced. The miscibility behavior of PCEMA is similar to that of a chlorinated polymer.     

Computation of surface energy and surface segregation phenomena of perfluorinated copolymers and blends – A molecular modeling approach

In this paper, we studied the surface properties and surface segregation phenomena of perflourinated copolymers and blends using molecular mechanics (MM) and molecular dynamics (MD) simulation in the NVT ensemble. The importance of functional group, 1H, 1H-dihydroperfluorohendecyl methacrylate (F10MA) and their surface preference over polymer backbone segments viz., methyl methacrylate (MMA) has been investigated. We have shown that degree of blockiness and change in chain architecture have significant effects on surface energy values. Surface energy differences between MMA and F10MA segments have been asserted by introducing a surface critical parameter, χ_s. Computations have been carried out to obtain bulk properties like cohesive energy density (CED) and solubility parameter (δ) by performing MM and MD simulations. Surface energies of MMA/F10MA blends have been computed by bulk pressure–volume–temperature (PVT) properties. Molecular dynamics simulation using NPT ensemble has been used to obtain specific volume as a function of temperature for different compositions of MMA/F10MA blends. From these results and using the equation of state approaches, thermal expansion coefficient has been obtained to calculate PVT parameters. These surface energy values compare well with the surface energy data calculated by the Zisman equation. Finally, the surface-enrichment behavior of F10MA components in the blend has been examined.     

Poly(ethylene oxide)/poly(methyl methacrylate) blends: Influence of tacticity of poly(methyl methacrylate) on blend structure and miscibility

The influence of different configurations of poly(methyl methacrylate) on the miscibility and superstructure of poly(ethylene oxide)/poly(methyl methacrylate) (PEO/PMMA) blends was examined using small-angle X-ray scattering and differential scanning calorimetry. The blends prepared by solution casting were isothermally crystallized at 48°C. The miscibility, the melting behaviour, the glass transition temperature and the structural parameters of the blends were strongly dependent on the tacticity and blend composition. The small-angle X-ray intensity profiles were analysed using a recently developed methodology. For the poly(ethylene oxide)/atactic poly(methyl methacrylate) (PEO/APMMA) and poly(ethylene oxide)/syndiotactic poly(methyl methacrylate) (PEO/SPMMA) blends, the long period and the amorphous and transition region thicknesses increased with increase of PMMA content, whereas for the poly(ethylene oxide)/isotactic poly(methyl methacrylate) (PEO/IPMMA) blends they are independent of composition. The structural properties of the blends were attributed to the presence of non-crystallizable material in the interlamellar or interfibrillar regions, depending on PMMA tacticity. From the glass transition and melting temperatures, it has been supposed that one homogeneous amorphous phase is present in the case of PEO/APMMA and PEO/SPMMA blends and that the PEO/IPMMA amorphous system is phase-separated. The free-volume contribution to the energy of mixing for the various tactic PMMAs is hypothesized to be responsible for the difference in mixing behaviour.     

New method of determining miscibility in binary polymer blends through hydrodynamic interaction: The free volume approach

A new method has been developed to determine the probability of miscibility in binary polymer blends through hydrodynamic interaction. This is achieved by the measurement of the free volume content in blends of carefully selected systems—styrene acrylonitrile (SAN)/poly(methyl methacrylate) (PMMA), PMMA/poly(vinyl chloride) (PVC), and PVC/polystyrene (PS)—with positron annihilation lifetime spectroscopy. The free volume content can predict the miscible/immiscible nature of the blends but provides no information on the extent of miscibility for different compositions of the blends. We have generalized a model used to understand the viscometric behavior of polymer/solvent systems to polymer/polymer systems through the free volume approach. This model provides two important parameters: a geometric factor (γ) and a hydrodynamic interaction parameter (α). γ depends on the molecular architecture, whereas α accounts for the excess friction at the interface between the constituents of the blend, and we propose that α can serve as a precursor to miscibility in a system and indicate which composition produces a high probability of miscibility. The efficacy of this proposition has been checked with measured free volume data for the three blend systems. The SAN/PMMA system produces a maximum α value of ?209 at 20% PMMA; PVC/PMMA produces a maximum α value of ?57 at 10% PMMA. Interestingly, for the PS/PVC system, α is close to zero throughout the entire concentration range. Therefore, we infer that α is perhaps an appropriate parameter for determining the composition‐dependent probability of miscibility in binary blend systems. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Miscibility in blends of polystyrene and poly(methyl methacrylate) studied by nonradiative energy transfer

Summary The miscibility of anthracene-labelled polystyrene (PS) in blends with carbazole-labelled poly(methyl methacrylate) (PMMA) was examined by the nonradiative energy transfer (NET) technique. It was found that the miscibility is relatively insensitive to the PMMA component molecular weight which has the range from 4.70x10⁵ to 2.36x10⁶. However, the miscibility is sensitive to the PS component molecular weight which has the range from 8.22x10⁴ to 4.68x10⁵. The observation from transmission electron microscopy is consistent with the results obtained from NET.     

Compatibility of polyvinyl alcohol and poly(methyl vinyl ether-co-maleic acid) blends estimated by molecular dynamics

The CSIR has developed a novel oxygen barrier technology for plastics packaging based on interpolymer complex formation between PVOH (polyvinyl alcohol) and PMVE-MA (poly(methyl vinyl ether-co-maleic acid)). As interpolymer complexation interactions are strongly dependent on stoichiometric ratios, the estimation of the optimum blend ratio is an important component of blend design.This study used molecular dynamics modelling to predict the ratio of optimum interaction for PVOH:PMVE-MA blends. Amorphous cells were constructed containing blends of short-chain repeat units of PVOH and PMVE-MA. The oligomers were equilibrated using both NVT and NPT dynamics and the cohesive energy densities (CED's) of the models were computed. From the CED's, energies of mixing and Flory-Huggins Chi Parameter (χ) values were estimated.The χ-values were negative for all blends, indicating favorable interaction between the two polymers. The minimum χ-values were found around 0.6-0.7 mass fraction of PMVE-MA, which agrees well with experimental viscosity results (this work), which indicated optimum interaction around 0.7 mass fraction PMVE-MA. These results confirm that molecular dynamics can be used as a tool for investigating interpolymer complexation phenomena.     

Miscibility of poly(α-methyl siyrene-co-acrylonitrile) with polyacrylates and polymethacrylates

A copolymer formed from 30 percent acrylonitrile and 70 percent α methyl styrene by weight, or αMSAN, has been examined for miscibility in blends with various polyacrylates and polymethacrylates. None of the polyacrylates or poly(vinyl acetate) were miscible with α-MSAN at room temperature or above. The methyl and ethyl esters of the polymethacrylate series (PMMA, PEMA) proved to be miscible with α MSAN, but none of the higher homologues were miscible under these conditions. Blends of both PMMA and PEMA with α MSAN exhibited lower critical solution temperatures. The observed cloud points decreased as PMMA molecular weight increased up to 10⁵ where kinetic effects caused an apparent reversal of this trend. Atactic PMMA interacts more strongly with αMSAN than does either isotactic PMMA or atactic PEMA. These structural effects are compared with similar trends found in other systems.     

Influence of molecular weight of poly (methyl methacrylate) on its miscibility with poly (vinyl chloride) in the solution

In this work, the molecular weight effect on miscibility between poly(vinyl chloride) (PVC) and poly(methyl methacrylate) (PMMA) in cyclohexanone(CH) solutions at 30 °C was examined by the viscometric method. Three samples of PMMA were prepared by emulsion polymerization, which molecular weights were changed by tert-dodecyl-mercaptan (TDDM) content. The parameter Δb is used to predict polymer-polymer miscibility of PVC/PMMA/cyclohexanone blend. Δb values indicated that the highest molecular weight of PMMA is immiscible with PVC resin. The molecular weight of PMMA decrease with the increase of the contention of TDDM, and the contribution of miscibility PVC/PMMA blend in CH is better.     

Effect of copolymer composition on the miscibility of blends of styrene-acrylonitrile copolymers with poly (methyl methacrylate)

The phase behaviour for blends of various polymethacrylates with styrene-acrylonitrile (SAN) copolymers has been examined as a function of the acrylonitrile content of the copolymer. Poly(methyl methacrylate), poly(ethyl methacrylate) and poly(n-propyl methacrylate) were found to be miscible with SANs over a limited window of acrylonitrile contents while no SANs appear to be miscible with poly(isopropyl methacrylate) or poly(n-butyl methacrylate). These conclusions were reached on the basis of lower critical solution temperature (LCST) and glass transition temperature behaviour. All miscible blends exhibited phase separation on heating, LCST behaviour, at temperatures which varied greatly with copolymer composition. An optimum acrylonitrile (AN) level ranging from about 10 to 14% by weight resulted in the highest temperatures for phase separation which has important implications for selection of SANs to produce homogeneous mixtures by melt processing. The basis for miscibility in these systems is evidently repulsion between styrene and acrylonitrile units in the copolymer as explained by recent models. The excess volumes for all blends are zero within experimental accuracy which suggests that the interactions for miscibility are relatively weak even for the optimum AN level. This interaction becomes smaller the larger or more bulky is the alkyl side group of the polymethacrylate.