Phase behavior of inverse microemulsions for the polymerization of acrylamide in near-critical and supercritical continuous phases

Journal Article · Thu Jan 11 00:00:00 EST 1990 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100364a059· OSTI ID:6730415

Beckman, E J; Smith, R D ^[1]

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1. Pacific Northwest Laboratories, Richland, WA (USA)

The inverse microemulsion polymerization of water-soluble acrylamide monomers within near-critical and supercritical alkane continuous phases provides a potential route for production of polymers with novel physical properties and at high reaction rates. In order to define conditions for a model polymerization process, the phase behavior of a nonionic surfactant/acrylamide/water system in near-critical and supercritical mixtures of ethane and propane was examined. Acrylamide was found to act as a cosurfactant due to its short chain length and hydrophilic character and this is probably coordinated about the surfactant's ethylene oxide units at the interface, rather than residing in the micelle core. The effects of temperature and composition on the phase behavior can be qualitatively explained from results on C{sub i}E{sub j}/water/alkane systems at atmospheric pressure by using either generalized ternary liquid-phase diagrams or a model that considers micelle-micelle and micelle-fluid interactions. Increasing pressure up to 550 bar acts to shrink the various two-component phase envelopes which govern the phase behavior of the multicomponent system and thus increases stability. At constant dispersed-phase composition and temperature, the clearing pressure of the system depends on the ethane/propane ratio only via the fluid density, possibly due to the nearly ideal mixing behavior of these two alkanes at high pressure. The ramifications of the phase behavior for the choice of polymerization conditions are discussed.

• OSTI ID: 6730415
• Journal Information: Journal of Physical Chemistry; (USA), Vol. 94:1; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
36 MATERIALS SCIENCE
MICROEMULSIONS
PHASE STUDIES
ACRYLAMIDE
DATA ANALYSIS
ETHANE
EXPERIMENTAL DATA
MEASURING INSTRUMENTS
MEASURING METHODS
POLYMERIZATION
PROPANE
SUPERCRITICAL STATE
ALKANES
AMIDES
CHEMICAL REACTIONS
COLLOIDS
DATA
DISPERSIONS
EMULSIONS
HYDROCARBONS
INFORMATION
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
400201* - Chemical & Physicochemical Properties
360603 - Materials- Properties