Thermal properties of hydrophobically modified methacrylic acid–ethyl acrylate copolymer solutions

Authors

  • K. C. Tam,

    Corresponding author
    1. School of Mechanical and Production Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798
    • School of Mechanical and Production Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798
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  • W. K. Ng,

    1. School of Mechanical and Production Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798
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  • R. D. Jenkins

    1. The Dow Chemical Company, UCAR Emulsion Systems, 410 Gregson Drive, Cary, North Carolina 27511, USA
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Abstract

The thermal behavior of a water-soluble associating polymer system, hydrophobically modified alkali-soluble emulsion (HASE) polymer, was investigated. This polymer contains a methacrylic acid–ethyl acrylate copolymer backbone with 1 mol % of pendant hydrophobic groups grafted to it. The thermal behavior of the HASE polymer exhibits different trends compared to the hydrophobic ethoxylated urethane (HEUR) system. The lifetime of the hydrophobic junction of the HASE polymer increases with temperature due to the increase in the entropy of the system. However, the structural relaxation time decreases with temperature, caused by the enhanced Brownian dynamics of polymer chains. The relaxation behavior of HASE polymers is either governed by the lifetime of the hydrophobic junction, the structural relaxation time, or a combination of both, depending on the degree of network formation and temperature. Temperature studies indicated that the transient network theory proposed by Tanaka and Edwards is inadequate for describing the activation process of hydrophobic junctions in the HASE associative polymer. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 604–612, 2004

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