Miscibility behavior of syndiotactic and atactic polystyrene

Ermer, Hubert; Thomann, Ralf; Kreßler, Jörg; Brenn, R.; Wünsch, J. R.

doi:10.1002/macp.1997.021981126

Cited by 28 publications

(16 citation statements)

References 32 publications

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“…However, this result does not con®rm the complete miscibility because there is only a small difference in T g of the two neat polymers [9]. In order to get a deeper insight into the miscibility of the two homopolymers both diffusion [9] and modulated Differential scanning calorimetry (DSC) [10,11] experiments have been carried out. All experimental results clearly demonstrated the presence, for these blends, of a single T g that is also dependent on composition according to Fox equation.…”

Section: Introductionmentioning

confidence: 99%

Blends of syndiotactic polystyrene with SEBS triblock copolymers

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et al. 2002

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Blending of styrene-b-(ethylene-co-1-butene)-b-styrene (SEBS) triblock copolymers with syndiotactic polystyrene (PSsyn) has been performed in a Brabender mixer above the higher glass transition temperature of the triblock copolymer but below the PSsyn melting point. The large excess of the triblock copolymer over the homopolymer as well as the signi®cant amount of plasticized amorphous PSsyn phase allowed the easy processing under the used temperature conditions with good interface compatibility. The consequent interfacial adhesion between the amorphous PS phase and the unmelted PSsyn crystallites affects both the ®nal morphology of the blend as well as its dynamic behavior. Indeed, such solid particles act as reinforcing point of the overall blend structure, as evidenced by scanning electron microscopy. Moreover, they contribute to a T g increase in the order of 20 8C with respect to pure SEBS and to an appreciable conservation of mechanical properties at temperatures higher than the T g of the PS blocks of SEBS. The mechanical and thermal behavior of the synthesized blends has been studied and tentatively correlated to the molecular weight ratio between PSsyn and the PS blocks of SEBS. q

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Section: Introductionmentioning

confidence: 99%

Blends of syndiotactic polystyrene with SEBS triblock copolymers

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et al. 2002

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“…[7] Work by Ermer et al has tentatively proposed that sPS and aPS might be at least partially miscible based on the results of solvent diffusion behavior in the blends. [8] Recent work in this laboratory has followed up some points and successfully and positively proven miscibility in the aPS/sPS blend by utilizing examination of the interaction parameter from measurements of the equilibrium melting point from the thermodynamics point of view. [9] Interactions between isomeric polymers, even when miscible, are expectedly low.…”

Section: Introductionmentioning

confidence: 99%

Miscibility in Blends of Isotactic/Syndiotactic Polystyrenes at Melt or Quenched Amorphous Solid State

Woo

2006

Macro Materials & Eng

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Summary: Miscibility in amorphous phase and behavior in a crystalline phase of blends of two semicrystalline and isomeric polymers, isotactic polystyrene (iPS) and syndiotactic polystyrene (sPS), was probed. Optical and scanning electron microscopy results indicate no discernible heterogeneity in iPS/sPS blends in either melt state or rapidly quenched amorphous super‐cooled state, while the Tg behavior of the quenched amorphous blends shows an intimately mixed state of two polymer chains. The crystal forms of the blends were further analyzed to provide additional evidence of miscibility in the amorphous domain. The sPS in the iPS/sPS blends upon melt crystallization was found to predominantly exist as the more stable β‐form (rather than mixed β‐form and α‐form in neat sPS), which also suggests evidence of miscibility in the iPS/sPS blends. The melting behavior of semicrystalline sPS in the iPS/sPS mixtures was analyzed using the Flory‐Huggins approach for estimation of interactions. By measuring the equilibrium melting point of the higher‐melting sPS species in the sPS/iPS blends, a small negative value, for the interaction parameter (χ ≈ −0.11) was found. Further, by introducing a third polymer, poly(2,6‐dimethyl‐p‐phenylene oxide) (PPO), a ternary iPS/sPS/PPO blend system was also proven miscible, which constituted a further test for stable phase miscibility in the iPS/sPS blend. General nature of miscibility in blends composed of two crystalline isomeric polymers is discussed. Issues in dealing with blends of polymers of the same chemical repeat unit but different tacticities were addressed.X‐ray diffractograms for neat sPS and iPS/sPS blends, each having been isothermally crystallized at 245 °C for 4 h.magnified imageX‐ray diffractograms for neat sPS and iPS/sPS blends, each having been isothermally crystallized at 245 °C for 4 h.

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“…Moreover, the solubility of the syndiotactic component into the atactic PS domains of the copolymers should be reasonably ensured by the demonstrated miscibility in solution of PSsyn with its atactic stereoisomer. In fact both modulated DSC [14,15] and diffusion experiments [16] clearly demonstrated for these blends the presence of a single T g , that is also dependent on composition according to Fox equation.…”

Section: Introductionmentioning

confidence: 99%

Blends of Syndiotactic Polystyrene with SBS Triblock Copolymers

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Ruggeri³

et al. 2001

Macromol. Chem. Phys.

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Blending of polystyrene‐block‐polybutadiene‐block‐polystyrene (SBS) triblock copolymers with syndiotactic polystyrene (PSsyn) has been performed in a Brabender mixer above the glass transition temperature of the triblock copolymer but below the melting point of PSsyn. The presence of a large excess of amorphous SBS (at least 70 wt.‐%) as well as of the amorphous PSsyn phase (about 60 wt.‐%, also above its Tg) allowed the easy mixing of the components. In contrast, the presence of unmelted PSsyn crystallites affects both the final morphology of the blend as well as its dynamic behavior. Indeed, according to the dynamic thermomechanical analysis (DMTA) data it is possible to suggest that such solid particles act to reinforce the overall blend structure (as in composite materials filled with inorganic solid particles). Similar behavior is also observed for the SBS copolymer alone below the Tg of the styrene blocks, Tg (PS). This conclusion is supported by both the compatibility of the blends, and the thermal and dynamic thermomechanical behavior at T > Tg (PS) as investigated by means of Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM) and DMTA. The results obtained are tentatively compared with those of similar blends obtained from toluene solution.

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Miscibility behavior of syndiotactic and atactic polystyrene

Cited by 28 publications

References 32 publications

Blends of syndiotactic polystyrene with SEBS triblock copolymers

Blends of syndiotactic polystyrene with SEBS triblock copolymers

Miscibility in Blends of Isotactic/Syndiotactic Polystyrenes at Melt or Quenched Amorphous Solid State

Blends of Syndiotactic Polystyrene with SBS Triblock Copolymers

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