title: Theoretical Study of Network Formation and Mechanical Properties of Physical Gels with a Well-Defined Junction Structure.
abstract: A statistical-mechanical theory of thermoreversible gelation considering loops for the system consisting of bifunctional polymer units carrying A functional groups and trifunctional units carrying B functional groups at their ends is constructed. We obtain the sol-gel transition line and the properties of the post-gel region as functions of the polymer concentration, temperature, association constant, and loop parameter using the present theory. In this article, we calculate the number concentration of elastically effective chains in the gel region and obtain the shear modulus by an application of the phantom network theory. The shear modulus obtained by this theory is lower than that obtained by conventional theory because of loop formation. We find that these theoretical results are in good agreement with the experimental data.
authors.affiliation: Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University , Katsura, Kyoto 615-8510, Japan.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Ozaki
authors.affiliation: Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University , Katsura, Kyoto 615-8510, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Koga