New miscible blends composed of polysulfone and poly(1-vinylpyrrolidone-co-acrylonitrile) copolymers and their phase behavior

The miscibility of polysulfone, PSf, blend with poly(1-vinylpyrrolidone), PVP, and that of PSf blend with poly(1-vinylpyrrolidone-co-acrylonitrile) copolymers, P(VP-AN), containing various amount of VP were explored. Even though PSf did not formed miscible blends with PVP when both components had high molecular weight, it formed miscible blend with PVP by decreasing molecular weight of PVP. PSf also formed homogeneous mixtures with P(VP-AN) containing AN from 2 to 16 wt%. These miscible blends underwent phase separation on heating caused by LCST-type (lower critical solution temperature-type) phase behavior. The phase separation temperature of miscible blends first increases with AN content, goes through a maximum centered at about 8 wt% AN. Interaction energies of binary pairs involved in blends were evaluated from the observed phase boundaries using the lattice-fluid theory. The decline of the contact angle between water and blend film by increasing P(VP-AN) content in blend indicated that the hydrophobic properties of PSf could be improved by blending with P(VP-AN) copolymers.     

Miscibility of DMPC‐TMPC copolycarbonate/SMMA copolymer blends and their interaction energies of binary pairs involved in blends

The isothermal miscibility map and phase‐separation temperatures caused by lower critical solution temperature‐type phase behavior for blends of poly[2,2,‐propane‐bis{4‐(2‐methyl phenyl)} carbonate]‐poly[2,2,‐propane‐bis{4‐(2,6‐dimethyl phenyl)} carbonate] (DMPC‐TMPC) with poly[(styrene)‐co‐(methyl methacrylate)] (SMMA) copolymers have been determined. SMMA copolymers containing equal to or less than 37 wt% MMA formed miscible blends with DMPC‐TMPC copolycarbonates containing equal to or more than 60 wt% TMPC. The observed phase‐separation temperatures indicate that the miscibility decreases as the DMPC content in DMPC‐TMPC increases, while addition of MMA to the styrene initially increases miscibility with DMPC‐TMPC but ultimately leads to immiscibility. The binary interaction energies involved in these blends were calculated from the phase boundaries using the lattice‐fluid theory combined with the binary interaction model. The spinodal temperatures predicted from the lattice‐fluid theory using the calculated interaction energies are similar to the experimental phase‐separation temperatures. Copyright © 2004 Society of Chemical Industry     

Changes in the miscibility of binary and ternary blends having the same chemical components and compositions

The phase behavior of ternary blends of dimethylpolycarbonate (DMPC), tetramethyl polycarbonate (TMPC), styrene-acrylonitrile (SAN) copolymer has been explored. The experimental phase behavior of ternary blends was compared with that of binary blends having the same chemical components and compositions except that the DMPC and TMPC were present in the form of copolycarbonates (DMPC-TMPC). Miscible region of DMPC/TMPC/SAN ternary blends is narrower than that of DMPC-TMPC/SAN binary blends. In addition, phase separation temperature of binary blend was higher than that of corresponding ternary blend. However, the entropic and energetic terms of ternary blends were more favorable for miscibility than those of binary blends. To understand the phase behavior of blends, phase stability conditions of binary and ternary blends were analyzed. Some ternary blends that have negative interaction energy were not miscible because these blends do not satisfy stability conditions. It was revealed that the addition of component, accompanied by the asymmetry in the binary interactions, results in destabilization of blend.     

Phase behavior of binary mixtures of styrene/acrylonitrile copolymers and aliphatic polyesters

The phase behavior of binary mixtures of copolymers containing varying amounts of styrene and acrylonitrile (SAN) with a large range of aliphatic polyesters was examined. Miscibility was observed over a limited range of AN contents of the SANs, for each polyester, while similarly for each SAN, miscibility was only observed over a limited range of polyester molecular structures. Thermodynamic interaction parameters for the miscible blends were obtained by analysis of the depression of the polyester melting point. A binary interaction model was used to correlate the data and six group interaction parameters were deduced by subdividing the polyester and SAN copolymer repeating units in three different ways. It is concluded that there is a strong repulsion between the segmental units within the polyesters and within the SAN copolymers, which is an important factor in the observed phase behavior.     

Investigation on the miscibility of the blends of poly(methyl methacrylate) and poly(styrene‐co‐acrylonitrile)

The miscibility was investigated in blends of poly(methyl methacrylate) (PMMA) and styrene‐acrylonitrile (SAN) copolymers with different acrylonitrile (AN) contents. The 50/50 wt % blends of PMMA with the SAN copolymers containing 5, 35, and 50 wt % of AN were immiscible, while the blend with copolymer containing 25 wt % of AN was miscible. The morphologies of PMMA/SAN blends were characterized by virtue of scanning electron microscopy and transmission electron microscopy. It was found that the miscibility of PMMA/SAN blends were in consistence with the morphologies observed. Moreover, the different morphologies in blends of PMMA and SAN were also observed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Blends of imidized acrylic polymers with SAN copolymers and with PVC

A series of imidized acrylic polymers of varying structural composition generated by reaction of methylamine with poly(methyl methacrylate) were blended with a range of styrene/acrylonitrile or SAN copolymers (0–33% AN) and with poly(vinyl chloride). On the basis of glass transition behavior determined by differential scanning calorimetry, some but not all imidized acrylic structures were found to be miscible with PVC and with SAN copolymers within a limited window of AN levels. Acid functionality in the imidized acrylics appears to hinder their miscibility with SAN rather significantly and with PVC to a lesser extent. Miscible SAN blends showed lower critical solution temperature behavior whereas miscible blends with PVC did not up to the highest attainable temperatures. The composition factors that influence the phase behavior are described and interpreted in terms of possible mechanisms.     

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     

Miscibility of poly(styrene-co-acrylonitrile) with random copolymers of tetramethyl bisphenol-A polyarylate and tetrabromo bisphenol-A polyarylate

Summary Tetramethyl bisphenol-A polyarylate (TMPAR) was miscible with poly(styrene-coacryloni trile) 's(SANs) containing 4, 7, 10, and 13wt% of acrylonitrile(AN) repeating unit. As the content of tetrabromo bisphenol-A polyarylate(TBPAR) repeating unit in the random copolymer of TMPAR and TBPAR was increased, the miscibility window in the blends with SANs was narrowed. The intramolecular repulsion between styrene and AN repeating units in SAN was suggested to be the main driving force for the miscibility of SANs with the random copolymers of TMPAR and TBPAR.     

Effects of AN-contents and shear flow on the miscibility of PC/SAN blends

The miscibility of polycarbonate (PC) with styrene-co-acrylonitrile random copolymer (SAN) has been systematically investigated as functions of acrylonitrile content and shear flow. Various AN-contents ranged from 11 to 74 wt% and different simple shear flow values up to 90 s⁻¹ have been used to explore the effect of both material and proceeding parameters on the miscibility of PC and SAN blends. The finest phase dispersion of the SAN particles was observed at AN=25 wt% for PC/SAN=70/30 blends under the same processing condition using scanning electron microscope (SEM). The obtained morphologies indicated that PC and SAN could form a partial miscibility blend and the maximum miscibility occurred at AN=25 wt%. This observation was supported by considering the shifts in the glass processes of the two rich phases of the blend using the dynamical mechanical analysis (DMA) measurements. The optimum interaction of the two components at AN=25 wt% calculated from ellipsometric technique was found to be the only responsible parameter for the high miscibility of the blend. The viscoelastic properties of the pure polymer components were found to play a minor role in the obtained morphologies. The effect of simple shear flow on the morphology of PC/SAN-25=70/30 blend has been also investigated using a special shear apparatus of parallel plate geometry. It has been found that the dispersed phase of SAN was elongated and broken-up in the direction of flow with weaker contrast at high shear rates. The shear rate was found to enhance the miscibility of SAN (dispersed phase) in the PC matrix to a great extent as seen in the weak contrast of the two phases observed by transmission electron microscope (TEM).     

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.     

PVC／ABS共混体系的相容性与形态结构研究

采用种子乳液聚合技术在聚丁二烯（PB）乳胶粒子上接枝共聚苯乙烯（St）、α-甲基苯乙烯（α—MSt）和丙烯腈（AN）单体,合成了一系列不同AN结合量的ABS和α—MABS接枝共聚物。将其与聚氯乙烯（PVC）树脂熔融共混制得了PVC／AtkS共混物,利用扫描电镜（SEM）、透射电镜（TEM）和动态力学分析仪（DMA）对共混物的相容性和相结构进行了表征。结果发现,在PVC／ABS共混体系中,尽管改变接枝SAN共聚物的AN结合量,PVC和ABS接枝共聚物均为不相容体系;在ABS接枝共聚物中引入α-MSt后,当接枝SAN共聚物的AN结合量为18．7％～23．6％（质量分数）时,共混物在室温以上只存在1个tanδ峰,共混物成为相容体系,当AN结合量达到32．1％（质量分数）时,共混物成为部分相容体系。共混物的相区尺寸明显地依赖于接枝SAN共聚物中的AN结合量,与动态力学性能结果表现出良好的吻合。     

Effect of the composition of α-MSAN copolymer on the miscibility of PVC/α-MSAN blends

A series of α-methylstyrene, styrene, and acrylonitrile (α-MSAN) copolymers with different acrylonitrile (AN) contents were synthesized by altering α-MSt, St, and AN ratios with emulsion copolymerization method. By melt-blending these copolymers with PVC resin and di-isooctyl phthalate (DOP), PVC/α-MSAN, and PVC/α-MSAN/DOP blends were prepared. The miscibility and morphology of the blends were investigated by dynamic mechanical analysis (DMA) and scanning electron microscopy. The PVC is immiscible with SAN by melt-mixing, whereas PVC is miscible with α-MSAN (α-MSt/St = 1/1) if AN weight percent is within the window range of 20–25 wt %, and α-MSAN (not containing St) with 35 wt % AN is miscible with PVC even when they are blended by melt-mixing. Replacement of styrene with α-methylstyrene widens the miscibility window with PVC. The miscibility of PVC/α-MSAN blends is substantially improved with the increasing α-MSt content in α-MSAN copolymer containing identical AN content. When DOP was introduced into the PVC/α-MSAN (α-MSt/St = 1/1) blends, a single tan δ peak over room temperature in DMA detection is found as AN content in α-MSAN copolymer is within the range of 15–25 wt %, and SEM observation also shows that the blends are homogeneous. When the AN content in α-MSAN copolymer is over 35 wt %, the presence of DOP causes the phase domain extended. The phase domain size of the PVC/α-MSAN/DOP blends intensively depends on AN content in α-MSAN copolymer. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Miscibility windows in ternary polymer blends of a polyester,polymethacrylate and poly(styrene‐co‐acrylonitrile)

Miscibility, phase diagrams and morphology of poly(ε‐caprolactone) (PCL)/poly(benzyl methacrylate) (PBzMA)/poly(styrene‐co‐acrylonitrile) (SAN) ternary blends were investigated by differential scanning calorimetry (DSC), optical microscopy (OM), and scanning electron microscopy (SEM). The miscibility window of PCL/PBzMA/SAN ternary blends is influenced by the acrylonitrile (AN) content in the SAN copolymers. At ambient temperature, the ternary polymer blend is completely miscible within a closed‐loop miscibility window. DSC showed only one glass transition temperature (T_g) for PCL/PBzMA/SAN‐17 and PCL/PBzMA/SAN‐25 ternary blends; furthermore, OM and SEM results showed that PCL/PBzMA/SAN‐17 and PCL/PBzMA/SAN‐25 were homogeneous for any composition of the ternary phase diagram. Hence, it demonstrated that miscibility exists for PCL/PBzMA/SAN‐17 and PCL/PBzMA/SAN‐25 ternary blends, but that the ternary system becomes phase‐separated outside these AN contents. Copyright © 2003 Society of Chemical Industry     

Compatibility behavior in thermoplastic polymer blends containing poly(t-butylstyrene-co-acrylonitrile)

The phase behavior of a series of binary component polymer blends of poly(ε-caprolactone) (PCL) and poly(t-butylstyrene-co-acrylonitrile) (TBSAN) containing varying contents of acrylonitrile (AN) was examined to determine the influence of copolymer composition and PCL content on blend miscibility or immiscibility. Thermal measurements were extensively used to determine phase behavior, i.e., a single compositionally dependent glass transition temperature implies blend miscibility. Otherwise, immiscibility is assumed to dominant blend behavior. It was determined that TBSAN and PCL form miscible blends over a broad range of AN content, i.e., spanning from below 43.2 mol % (19.8 wt %) to about 66.4 mol % (39.6 wt %), a range considerably different from that found in poly(styrene-co-acrylonitrile) copolymers. TBSAN-containing blends were found to be immiscible when the AN content is less than about 43 mol % or greater than about 67 mol %. Small-angle light-scattering and polarized light microscopy was used to probe the substantial morphological changes in the miscible blends. Little change was observed in the immiscible blends. These results clarify the phase separation observed in these blend systems. © 1993 John Wiley & Sons, Inc.     

Novel blends of alternating propene-carbon monoxide copolymers and styrenic copolymers

Summary Alternating propene-carbon monoxide copolymers (P-CO) were melt-blended with polystyrene, poly(styrene-co-acrylonitrile) (SAN), and with poly(styrene-co-maleic anhydride) (SMA). P-CO forms homogeneously miscible blends with SAN containing 25 wt% AN at the investigated blend compositions. The transparent blends have single, intermediate glass transition temperatures that fit the Fox equation. The elastic properties of P-CO at room temperature disappear upon blending with SAN because the T _g is driven above RT. Polystyrene and SMA are not miscible with P-CO and form heterogeneous blends with two glass transitions. This demonstrates that both the polarity of the styrenic copolymer and the nature of the comonomer govern its phase behavior. Received: 14 January 1999/Revised version: 19 April 1999/Accepted: 19 April 1999     

Water extraction of polyethyloxazoline from miscible and immiscible polymer blends

Blends of water-soluble polyethyloxazoline (PEOx) with a series of hydrophobic styreneacrylonitrile copolymers (SAN) of varying AN contents were immersed in water to determine the kinetics of water swelling and the extent of PEOx extraction. Copolymers containing 25 and 40% by weight of AN form miscible blends with PEOx; those containing higher and lower amounts of AN form immiscible mixtures with PEOx. A high degree of PEOx extraction was observed for the immiscible blends as expected, whereas surprisingly little PEOx was extracted from the miscible blends over periods up to 2 years in spite of a high degree of water swelling. Similar behavior has been noted for other blends of hydrophobic and hydrophilic polymers. In the present system, thermal analysis revealed that the sorption of large amounts of water induces a microphase separation of the two miscible polymers to form microdomains of SAN in which, evidently, segments of PEOx are entrapped to form physical cross-links that preclude disintegration of the sample and extraction of the PEOx whose phase is highly swollen by the sorbed water. It is proposed that a similar situation probably occurs for other blend systems exhibiting such behavior.     

Viscoelastic properties of blends of poly(methyl methacrylate) and poly(styrene‐co‐acrylonitrile) having various acrylonitrile contents

Dynamic viscoelastic properties of blends of poly(methyl methacrylate) (PMMA) and poly(styrene‐co‐acrylonitrile) (SAN) with various AN contents were measured to evaluate the influence of SAN composition, consequently χ parameter, upon the melt rheology. PMMA/SAN blends were miscible and exhibited a terminal flow region characterized by Newtonian flow, when the acrylonitrile (AN) content of SAN ranges from 10 to 27 wt %. Whereas, PMMA/SAN blends were immiscible and exhibited a long time relaxation, when the AN content in SAN is less than several wt % or greater than 30 wt %. Correspondingly, melt rheology of the blends was characterized by the plots of storage modulus G′ against loss modulus G″. Log G′ versus log G″ plots exhibited a straight line of slope 2 for the miscible blends, but did not show a straight line for the immiscible blends because of their long time relaxation mechanism. The plateau modulus, determined as the storage modulus G′ in the plateau zone at the frequency where tan δ is at maximum, varied linearly with the AN content of SAN irrespective of blend miscibility. This result indicates that the additivity rule holds well for the entanglement molecular weights in miscible PMMA/SAN blends. However, the entanglement molecular weights in immiscible blends should have “apparent” values, because the above method to determine the plateau modulus is not applicable for the immiscible blends. Effect of χ parameter on the plateau modulus of the miscible blends could not be found. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Polycarbonate blends with styrene/acrylonitrile copolymers

Lap shear adhesion between laminated sheets of polycarbonate and styrene/acrylonitrile copolymers exhibits a sharp maximum when the acrylonitrile content of the copolymers is in the range of 25–27% by weight. Observations of shifts in glass transitions of the two phases in melt-mixed polycarbonate/SAN blends suggest partial miscibility of one polymer in the other, and this solubility is at a maximum when the SAN copolymer has an acrylonitrile content in the same range causing maximum adhesion. Mechanical properties of injection-molded blends of polycarbonate with various SAN copolymers were also best when the acrylonitrile content was the same as that giving maximum adhesion. The partial miscibility behavior in blends as a function of acrylonitrile content of the copolymer is explained qualitatively in terms of a simple binary interaction model.     

The effects of PC‐PMMA block copolymer on the compatibility and interfacial properties of PC/SAN blends

Block copolymers of polycarbonate (PC) and polymethylmethacrylate (PMMA), PCb‐PMMA, were examined as compatibilizers for blends of PC with styrene‐co‐acrylonitrile (SAN) copolymer. PC‐b‐PMMA was added to blends of PC with SAN containing various amounts of AN. The average diameter of the dispersed particles was measured with an image analyzer, and the interfacial properties of the blends were analyzed with an imbedded fiber retraction (IFR) test and an asymmetric double cantilever beam fracture test. The average particle size and interfacial tension of the PC/SAN blends reached a minimum value when the SAN copolymer contained about 24 wt% AN. A maximum in the adhesion energy was also observed at the same AN content. Interfacial tension and particle size were further reduced by adding PC‐b‐PMMA to the PC/SAN blends. Fracture toughness of the blends was also improved by enhancing the interfacial adhesion by the addition of PC‐b‐PMMA. The addition of PC‐b‐PMMA copolymer was more effective at improving the interfacial properties of PC/SAN blends than was varying the AN content of the SAN copolymers. The interfacial properties of the PC/SAN blends were optimized by adding a block copolymer and using an SAN copolymer that had minimum interaction energy with PC.     

Melting point depression in poly(ɛ-caprolactone) / poly(styrene-co-acrylonitrile) blends

Summary The melting point depression of poly(-caprolactone)/poly(styrene-co-acrylonitrile) (PCL/SAN) blends with changes in acrylonitrile content of SAN and in blend ratio was investigated by differential scanning calorimetry. For the melting points at a constant blend ratio occur a minimum in dependence on the copolymer composition for blends containing about 20 wt% acrylonitrile in SAN. From melting point depression data a negative, binary interaction parameter was obtained for PCL/SAN blends containing a SAN with 19.2 wt% AN. By optical microscopy it can be shown that the shape of the spherulites changes with copolymer composition of SAN and blend ratio.