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Published July 1, 2015 | public
Journal Article

The linear rheological responses of wedge-type polymers


The linear rheological responses of a series of specially designed wedge-type polymers synthesized by the polymerization of large molecular weight monomers have been measured. These wedge polymers contained large side groups which contained three flexible branch chains per polymer chain unit. The master curves for these polymers were obtained by time temperature superposition of dynamic data at different temperatures from the terminal flow regime to well below the glass transition temperature, T_g. While these polymers maintained a behavior similar to that of linear polymers, the influence of the large side group structure lead to low entanglement densities and extremely low rubbery plateau modulus values, being near to 13 kPa. The viscosity molecular weight dependence was also somewhat higher than that normally observed for linear polymers, tending toward a power law near to 4.2 rather than the typical 3.4 found in entangled linear chains. The glassy modulus of these branched polymers is also found to be extremely low, being less than 100 MPa at T_g −60 °C.

Additional Information

© 2015 Wiley Periodicals, Inc. Received 2 November 2014; Revised 18 February 2015; Accepted 1 March 2015; Published online 27 March 2015. This research was supported primarily by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award No. DE-FG02- 05ER46218. Partial support was also provided the National Science Foundation under grant DMR-1207070 and by the John R. Bradford Endowment at Texas Tech University.

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