Anomalous mixing behavior of polyisobutylene with other polyolefins

Krishnamoorti, Ramanan; Graessley, William W.; Fetters, Lewis J.; Garner, Richard T.; Lohse, David J.

doi:10.1021/ma00108a064

Cited by 115 publications

(226 citation statements)

References 6 publications

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“…Bromobutyl blends with V2727 (EPDM) and EB68 are known to be miscible at room temperature and to be immiscible at higher temperatures. 16 This (lower critical solubility temperature (LCST)) behavior is observed at 50°C for EPDM and at 90-100°C for EB68. 16 The solubility parameter and structure of 1,2-polybutadiene are similar to those of EB68.…”

Section: Blends With V2727 Eb68 and 12-polybutadienementioning

confidence: 96%

“…16 This (lower critical solubility temperature (LCST)) behavior is observed at 50°C for EPDM and at 90-100°C for EB68. 16 The solubility parameter and structure of 1,2-polybutadiene are similar to those of EB68. 5,16 -18 Therefore, similar solubility and LCST behavior is expected for the 1,2-polybutadiene blends.…”

Section: Blends With V2727 Eb68 and 12-polybutadienementioning

confidence: 96%

“…These polymers exhibit solubility parameters that are 0.6-1.5 cal cm 3 larger than bromobutyl. 5,16 As a result, such polymers form immiscible blends with bromobutyl and will have a strong tendency to segregate either to or away from the surface. As a result of the high unsaturation of these polymers, the surface tensions of polychloroprene, 1,4-polybutadiene and the SBRs (44, 43 and 43 mJ m 2 , respectively) are much greater than that of the butyl rubbers (34 mJ m 2 ).…”

Section: Blends With Polychloroprene and 14-polybutadiene-based Polymentioning

confidence: 99%

“…Polymer EB32 has a solubility parameter that is very close to that of butyl rubber υ Butyl Rubber υ EB32 D C0.1 cal cc 1 0.5 , indicating that EB32 should show some miscibility with bromobutyl (recent experimental results exclude complete miscibility). 5,16 The surface tension of EB32 (¾34 mJ m 2 ; extrapolated from the surface tensions of polyethylene and poly 1-butene) is approximately the same as bromobutyl. These data indicate that there is no great driving force for EB32 migration to or away from the surface.…”

Section: Blends With Polyisoprene and Eb32mentioning

confidence: 99%

“…Also, EPDMs (such as V2727) have some potential as adhesion promoters. This potential can be improved by lowering the surface energy (increasing the propylene concentration) 16,17 of the EPDM, which will enhance surface migration, and by increasing the unsaturation (increasing the ENB concentration), which will enhance reactivity.…”

Section: Blends With V2727 Eb68 and 12-polybutadienementioning

confidence: 99%

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Surface chemistry of bromobutyl binary blends

Galuska

1999

Surf. Interface Anal.

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Section: Blends With V2727 Eb68 and 12-polybutadienementioning

confidence: 96%

Section: Blends With V2727 Eb68 and 12-polybutadienementioning

confidence: 96%

Section: Blends With Polychloroprene and 14-polybutadiene-based Polymentioning

confidence: 99%

Section: Blends With Polyisoprene and Eb32mentioning

confidence: 99%

Section: Blends With V2727 Eb68 and 12-polybutadienementioning

confidence: 99%

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Surface chemistry of bromobutyl binary blends

Galuska

1999

Surf. Interface Anal.

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

Maier

Thomann

Kreßler

et al. 1997

J. Polym. Sci. B Polym. Phys.

125

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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

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Recent developments in phase separation of polyolefin melt blends

Crist

Hill²

1997

J. Polym. Sci. B Polym. Phys.

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Saturated hydrocarbon polymers may be differentiated by the relative amount and placement of methylene, methyl, methine, and quaternary carbon moieties. While it has been known or suspected for some time that polyolefins of conventional molecular weight (Mw ≈ 100 kg/mol) with dissimilar chemical microstructures are most often immiscible in the liquid state, recent experiments with binary blends of model polyolefins have increased greatly our understanding of thermodynamic interactions between unlike chains. Model systems with methyl (−CH3) and ethyl (−C2H5) short‐chain branches give results, expressed as the Flory‐Huggins interaction parameter χ, that are nearly universal; repulsive interactions (χ > 0) are more pronounced at low temperatures, leading to liquid‐liquid phase separation at an upper critical solution temperature. Phase behavior of more complex systems (with distributions of chain microstructures and/or molecular weight) is generally consistent with predictions from model systems. An interesting exception is from work at Bristol on blends of lightly branched ethylene − α‐olefin copolymers with unbranched polyethylene as the minority species. Here the presence of two liquid phases is inferred under conditions not expected from model studies; effects of copolymer composition and molecular weight are also unusual. Recent theoretical work points to the importance of chain stiffness (established by short‐chain branching) in determining the thermodynamics of model blends. Nonrandom mixing of chains with different stiffness gives rise to an enthalpic χ, which may be negative under certain conditions. Other limitations of the Flory‐Huggins approach to describing blend energetics are considered. At present there is no theoretical basis for liquid‐liquid phase separation reported by the Bristol group. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2329–2353, 1997

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Anomalous mixing behavior of polyisobutylene with other polyolefins

Cited by 115 publications

References 6 publications

Surface chemistry of bromobutyl binary blends

Surface chemistry of bromobutyl binary blends

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

Recent developments in phase separation of polyolefin melt blends

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