Miscible Ternary Blend Research Articles

In Situ Chemical Modification of Thermoplastic Starch with Poly(L-lactide) and Poly(butylene succinate) for an Effectively Miscible Ternary Blend

Thermoplastic starch (TPS) is in situ ring-opening polymerized with L-lactide (L-LA) and directly condensed with a poly(butylene succinate) (PBS) prepolymer in an extruder using two different production pathways to demonstrate the concept “like dissolves like” in a miscible poly(lactide)/TPS/PBS (PLA/TPS/PBS) ternary blend. The TPS crystalline pattern changes from a VH-type to an EH-type after TPS modification with a hydrophobic-PLLA segment. Heteronuclear multiple-bond correlation confirmed the successful formation of PLLA-TPS-PBS copolymers via two different in situ chemical modification pathways (i.e., (I) step-by-step modification and (II) one-pot reaction). All obtained PLLA-TPS-PBS copolymers functioned as the miscible phase, enhancing PLA/PLLA-TPS-PBS/PBS ternary blend miscibility, especially the random structural PLLA-TPS-PBS-II copolymers created in an in situ one-pot reaction. However, the PLLA-TPS-PBS-I copolymers can enhance PBS crystallization only. While the random PLLA-TPS-PBS-II copolymers exhibit a homogeneous multi-phase dispersion and crystallization acceleration in both the PLA and PBS chains. Moreover, the storage modulus level of the PLA/PLLA-TPS-PBS-II/PBS ternary blend remains high with a downward temperature shift in the glass transition region, indicating a stronger and more flexible system. The practical achievement of in situ modified TPS and, consequently, a miscible PLA/PLLA-TPS-PBS/PBS ternary blend with favorable physical properties, reveal its potential application in both compostable and food contact packaging.

Ternary miscibility with specific interactions in novel blends comprising biodegradable polymers and a natural polyphenol

Novel miscible ternary blends comprising poly(ethylene azelate) (PEAz) and poly(e-caprolactone) (PCL), which are biodegradable polymers, and catechin, a natural polyphenol, were discovered. The inherent biodegradability of PEAz and PCL and the biocompatibility of catechin enable these blends to be used for manufacturing functional polymeric materials. The PEAz/catechin/PCL blends exhibit homogeneous phase morphology and one single Tg for each of the ternary compositions, demonstrating that the blends are with ternary miscibility. The phenomenon of melting point depression found in the blends confirmed that the PEAz/catechin/PCL blends are inherently miscible with thermodynamically favorable interactions. It also revealed that catechin formed hydrogen-bonding interactions with the polyesters PEAz and PCL in the ternary blends. Ternary miscibility in the PEAz/catechin/PCL blends might be mainly attributed to two factors: (1) a negligible ΔK effect resulting from the symmetric hydrogen-bonding interactions between catechin and PEAZ and between catechin and PCL, and (2) a minimal Δχ effect caused by a slight difference in the solubility parameters of PEAz and PCL in the blends. In these miscible ternary blends, the nonisothermal crystallization of crystalline polyesters was retarded as the catechin content was increased.

Miscibility enhancement and formation of interpenetrating spherulites in ternary blends of crystalline polymers

AbstractMiscible blends of three crystalline polymers, namely poly(butylene succinate) (PBS), poly(ethylene succinate) (PES), and poly(oxyethylene) (POE), exhibited interpenetrating spherulites, where a spherulite of one component grows inside the spherulites of other components. PBS and PES were immiscible above the melting points, Tm, of these substances, while ternary blends with POE showed miscibility, which depended on the molecular weight of POE. PBS and PES exhibited the same spherulitic growth process as in a miscible binary blend when they were crystallized from a homogeneous ternary melt. Spherulites of PBS, which is the highest‐Tm component, filled the whole volume first when a miscible ternary blend was quenched below Tm of POE, the lowest‐Tm component. Then, the blends showed either two types of crystallization processes. One was successive nucleation and growth of PES and POE spherulites, that is, PES nucleated and developed spherulites inside the PBS spherulites and then POE spherulites grew inside the interlocked spherulites of PBS and PES. The other was simultaneous growth and the formation of interpenetrating spherulites of PES and POE inside the PBS spherulites. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 706–711, 2010

Achieving miscible ternary polymer blends with hydrogen bonding

AbstractPoly(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

Interactions and prediction of phase diagrams in ternary blends comprising poly(vinyl acetate), poly(vinyl p‐phenol), and poly(methyl methacrylate)

AbstractThis study investigated and discovered a new miscible ternary blend system comprising three amorphous polymers: poly(vinyl acetate) (PVAc), poly(vinyl p‐phenol) (PVPh), and poly(methyl methacrylate) (PMMA) using thermal analysis and optical and scanning electron microscopies. The ternary compositions are largely miscible except for a small region of borderline ternary miscibility near the side, where the binary blends of PVAc/PMMA are originally of a borderline miscibility with broad Tg. In addition to the discovering miscibility in a new ternary blend, another objective of this study was to investigate whether the introduction of a third polymer component (PVPh) with hydrogen bonding capacity might disrupt or enhance the metastable miscibility between PVAc and PMMA. The PVPh component does not seem to exert any “bridging effect” to bring the mixture of PVAc and PMMA to a better state of miscibility; neither does the Δχ effect seem to disrupt the borderline miscible PVAc/PMMA blend into a phase‐separated system by introducing PVPh. Apparently, the ternary is able to remain in as a miscible state as the binary systems owing to the fact that PVPh is capable of maintaining roughly equal H‐bonding interactions with either PVAc or PMMA in the ternary mixtures to maintain balanced interactions among the ternary mixtures. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1147–1160, 2006

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

AbstractThe 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

Thermodynamic interactions in blends of poly(4‐tert‐butyl styrene) and polyisoprene by small‐angle neutron scattering

AbstractThe thermodynamic interactions between poly(4‐tert‐butyl styrene) [P(4tBS)] and 1,4‐polyisoprene (PI; both hydrogenous) were obtained as functions of the temperature, PI molecular weight, and blend composition through the examination of miscible ternary blends of these two components with a common miscible labeled polymer [90% 1,2‐deuterated polybutadiene (dPBD)] with small‐angle neutron scattering. The thermodynamic interaction parameters between P(4tBS) and dPBD and between P(4tBS) and PI increased with increasing temperature and were consistent with lower critical solution temperature behavior. Although the binary blends of P(4tBS) and dPBD exhibited phase separation at elevated temperatures, the thermodynamic interaction parameters between P(4tBS) and PI remained large and negative and independent of the PI molecular weight. Finally, the thermodynamic interactions for PI and P(4tBS) depended strongly on the ratio of PI to P(4tBS) and were also sensitive to the amount of dPBD present in the ternary blend. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3204–3217, 2004

Ringed spherulites in ternary polymer blends of poly(?-caprolactone), poly(styrene-co-acrylonitrile), and polymethacrylate

The relationship between ringed spherulite morphology, crystallization regimes/kinetics, and molecular interactions in miscible ternary blends of poly(e-caprolactone) (PCL), poly(benzyl methacrylate) (PBzMA), and poly(styrene-co-acrylonitrile) (SAN) was investigated by using differential scanning calorimetry (DSC), polarized optical microscopy (POM), and wide-angle X-ray diffraction (WAXD). The interactions resulted in the deviation of both experimental and calculated Tgs and formation of the specific morphology of the spherulitic structure. Ring-banded spherulites were observed in the PCL/PBzMA/SAN ternary blends. The width of ring bands changed with the blend ratio and the crystallization temperature. Additionally, both composition and wt% of AN in the SAN copolymer had an apparent effect on the morphology of PCL spherulites. Both the crystallization structure of lamellae and molecular interactions greatly influenced the ring bands of PCL spherulites. Furthermore, by using the Flory–Huggins approximation, the depression of the melting point showed that interactions in the PCL/PBzMA/SAN-17 blend were greater than in the PCL/PBzMA/SAN-25 blend. In the ternary blends, the great molecular interactions between amorphous and crystalline polymer resulted in better homogeneity and a larger band period of the extinction rings in the PCL spherulites.

Phase behavior of binary and ternary blends having the same chemical components and compositions

The phase behavior of binary blends of dimethylpolycarbonate-tetramethyl polycarbonate (DMPCTMPC) copolycarbonates and styrene-acrylonitrile (SAN) copolymers has been examined and then compared with that of DMPC/TMPC/SAN ternary blends having the same chemical components and compositions except that the DMPC and TMPC were present in the form of homopolymers. Both binary and ternary blends were miscible at certain blends compositions, and the miscible blends showed the LCST-type phase behavior or did not phase separated until thermal degradation temperature. The miscible region of binary blends is wider than that of the corresponding ternary blends. Furthermore, the phase-separation temperatures of miscible binary blends are higher than those of miscible ternary blends at the same chemical compositions. To explain the destabilization of polymer mixture with the increase of the number of component, interaction energies of binary pairs involved in these blends were calculated from the phase separation temperatures using lattice-fluid theory and then the phase stability conditions for the polymer mixture was analyzed with volume fluctuation thermodynamics.

Ternary miscibility in blends of three polymers with balanced binary interactions

AbstractThis study demonstrates and discusses ternary miscibility in a three‐polymer blend system based on balanced binary interactions. A truly miscible ternary blend comprising poly(ε‐caprolactone) (PCL), poly(benzyl methacrylate) (PBzMA), and poly(vinyl methyl ether) (PVME), was discovered and reported. Miscibility with phase homogeneity (excluding the PCL crystalline domain) in a wide composition range has been demonstrated using criteria of thermal transition behavior, cloud point, and microscopy characterization. At ambient temperature, the three‐polymer ternary system is completely miscible within the entire composition range (i.e., no immiscibility loop). However, at slightly elevated temperatures above the ambient. phase separation readily occurred in this originally miscible ternary blend. A quite low “lower critical solution temperature” (LCST) near 75°C was found for the ternary blend, which is much lower than any of those for the binary pairs. Balanced interactions with no offsetting Δχ among the three binary pairs were a key factor leading to a ternary miscible system.

A completely miscible ternary blend system of poly(3-hydroxybutyrate), poly(ethylene oxide) and polyepichlorohydrin

The miscibility of a ternary system of poly(3-hydroxybutyrate), poly(ethylene oxide) and polyepichlorohydrin was studied by differential scanning calorimetry. The three binary blend systems are individually miscible. All the ternary blends were found to be miscible as shown by the existence of a single glass transition temperature in each blend. The interaction parameters of the three binary pairs are of similar magnitude and do not lead to a “Δ χ” effect.

Influence of Competition Between Binary Pairwise Interactions on the Phase Behavior in Ternary Blends

There are three binary pairs in a ternary blend and competition exists among these pairwise interactions owing to the asymmetry of the interaction energies between these binary pairs, which will determine the overall phase behavior of the blend. The influence of molecular weight of the components on the asymmetry of the interactions was discussed based on a ternary copolymer blend poly(styrene-co-acrylonitile)/poly(styrene-comethylmethacrylate/poly(methyl methacrylate-co-acrylonitile) (SAN/SMMA/MAN). It has been demonstrated that the asymmetry of the interactions between different binary polymer pairs is driven not only by the difference of interaction parameters, i.e. the so-called Δξ effect, but also by the difference of chain length between different components in the mixture. If the two effects are coincident with each other, the asymmetry of the interactions will be intensified, promoting phase separation. On the other hand, the compatibility of the system may be improved remarkably as the two factors are in opposite directions. It implies that a miscible ternary blend may be available simply by exchanging the order of the molecular weight between the different components against the asymmetry direction caused by their corresponding interaction parameters, which is easier to do in many experimental conditions. © 1997 John Wiley & Sons, Ltd.

Completely miscible ternary blends—III. Poly(vinylidenefluoride)-poly(methyl methacrylate)-poly(vinyl acetate)

Ternary blends comprising poly(vinylidene fluoride) (PVDF), poly(methyl methacrylate) (PMMA), and poly(vinyl acetate) (PVAc) were examined by using differential scanning calorimetry (DSC) for thermal transition ( T g ) behaviour and optical observations for phase separation on heating or lower critical solution temperature (LCST) behaviour. It was found that the ternary blend system exhibits LCST behaviour, but there is no minimum on the cloud point surface of the ternary blends. All the ternary blends have a single T g which varied with overall blend composition, indicating that the ternary blend presents a homogeneous single amorphous phase, i.e. the three components are completely miscible in the amorphous state at all compositions. The overall crystallization rate of PVDF in the ternary blend decreases with the content of amorphous diluent comprising PMMA and PVAc. The crystallinity index of PVDF in both the binary and ternary blends decreases with increasing diluent content owing to the enhanced T g value of the system.

Self-vulcanizable ternary rubber blend based on epoxidized natural rubber, carboxylated nitrile rubber and polychloro-prene rubber: 2. Effect of blend ratio and fillers on properties

Mill-mixed blends of epoxidized natural rubber (ENR), carboxylated nitrile rubber (XNBR) and neoprene form a self-vulcanizable ternary blend system which can be reinforced by fillers such as carbon black and silica. The effect of fillers on processing characteristics and physical properties of self-vulcanizable blends is similar to that of conventional rubbers. The properties depend on blend ratio and type of filler. The blend in the gum state shows poor failure properties like gum ENR, but shows high resilience and low compression set. Abrasion loss and heat build-up properties of the blend are nearer to those of gum neoprene vulcanizate. The filled blends show lower heat build-up due to non-uniform distribution of fillers in the miscible ternary blend. Mooney viscosity and Mooney scorch time of the blend are found to be intermediate between the control mixes of ENR and XNBR, but the Monsanto rheometric torque values are closer to ENR.

Self-vulcanizable ternary rubber blend based on epoxidized natural rubber, carboxylated nitrile rubber and polychloroprene rubber: 1. Effect of blend ratio, moulding time and fillers on miscibility

Miscibility of the self-vulcanizable ternary blend based on epoxidized natural rubber (ENR), neoprene and carboxylated nitrile rubber (XNBR) depends on blend ratio. Miscibility is attained at an ENR content of 75 parts per 100 parts of neoprene/XNBR blend, irrespective of the neoprene/XNBR blend ratio. At lower ENR content, miscibility depends on neoprene/XNBR blend ratio. At a fixed ENR content, the higher the neoprene content in the neoprene/XNBR blend, the lower is the miscibility in the ternary blend system. Reinforcing fillers, such as silica and carbon black, cause phase separation in a miscible ternary blend. Variation in moulding time does not alter the miscibility, but shifts the glass transition temperature due to change in crosslink density.

Completely miscible ternary blends—I. poly(hydroxyether of bisphenol-A)-poly(vinyl methyl ether)-poly(ϵ-caprolactone)

Ternary blends comprising poly(hydroxyether of bisphenol-A), poly(vinyl methyl ether) and poly(ϵ-caprolactone) were examined by using differential scanning calorimetry for study of glass transition behaviour and optical observations for phase separation on heating or lower critical solution temperature (LCST) behaviour. It was found that the ternary blend system exhibits LCST behaviour and complete miscibility exists over the entire composition diagram for temperatures between the melting temperature of the PCL in the blends and the cloud point temperature.

Miscible ternary blends containing polycarbonate, SAN, and aliphatic polyesters

AbstractTernary blends comprising polycarbonate, (PC), poly(styrene‐co‐acrylonitrile) (SAN), and a polyester, either poly(1,4‐butylene adipate) (PBA), poly(1,4‐cyclohexanedimethylene succinate) (PCDS), or poly(ε‐caprolactone) (PCL), were found to be miscible based on the presence of a single glass transition temperature at many compositions. For all systems, the addition of just 1% by weight polyester resulted in a miscible blend for SAN/PC ratios of 1/1 and 3/1, and a region of immiscibility was generally observed for PC‐rich compositions with low polyester content. The melting point depression of PCL in the ternary and in binary mixtures was studied to obtain interaction parameters for the PCL/PC, PCL/SAN, and SAN/PC binaries. These parameters were used to calculate the locus of compositions which mark the boundary between single‐ and multiple‐phase behavior. Agreement between the calculated and experimental boundary was only fair. PCDS was found to be the most efficient of the three polyesters studied for solubilizing PC and SAN. SAN copolymer containing 25% acrylonitrile (AN), was found to be more easily solubilized in PC by PCDS than SAN containing 13% AN.

Calorimetric study of the miscibility of poly(α-methyl styrene-co-acrylonitrile)/poly(methyl methacrylate)/poly(ethyl methacrylate) ternary blends

The miscibility of poly(α-methyl styrene-co-acrylonitrile) (MSAN)/poly(methyl methacrylate) (PMMA)/poly(ethyl methacrylate) (PEMA) ternary blends was studied by DSC. PMMA is immiscible with PEMA, but the addition of MSAN helps make PMMA and PEMA more compatible. The formation of a miscible ternary blend is favored when there is a high MSAN and/or PMMA content in the blend.