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Linear Rheological Response of a Series of Densely Branched Brush Polymers

Hu, Miao and Xia, Yan and McKenna, Gregory B. and Kornfield, Julia A. and Grubbs, Robert H. (2011) Linear Rheological Response of a Series of Densely Branched Brush Polymers. Macromolecules, 44 (17). pp. 6935-6943. ISSN 0024-9297.

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We have examined the linear rheological responses of a series of welldefined, dense, regularly branched brush polymers. These narrow molecular weight distribution brush polymers had polynorobornene backbones with degrees of polymerization (DP) of 200, 400, and 800 and polylactide side chains with molecular weight of 1.4 kDa, 4.4 kDa, and 8.7 kDa. The master curves for these brush polymers were obtained by time temperature superposition (TTS) of the dynamic moduli over the range from the glassy region to the terminal flow region. Similar to other long chain branched polymers, these densely branched brush polymers show a sequence of relaxation. Subsequent to the glassy relaxation, two different relaxation processes can be observed for samples with the high molecular weight (4.4 and 8.7 kDa) side chains, corresponding to the relaxation of the side chains and the brush polymer backbone. Influenced by the large volume fraction of high molecular weight side chains, these brush polymers are unentangled. The lowest plateau observed in the dynamic response is not the rubbery entanglement plateau but is instead associated with the steady state recoverable compliance. Side chain properties affect the rheological responses of these densely branched brush polymers and determine their glassy behaviors.

Item Type:Article
Related URLs:
URLURL TypeDescription DOIArticle
McKenna, Gregory B.0000-0002-5676-9930
Kornfield, Julia A.0000-0001-6746-8634
Grubbs, Robert H.0000-0002-0057-7817
Additional Information:© 2011 American Chemical Society. Received: April 27, 2011. Revised: July 24, 2011. Publication Date (Web): August 4, 2011. This research was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award No. DE-FG02-05ER46218.
Funding AgencyGrant Number
Department of Energy (DOE)DE-FG02-05ER46218
Issue or Number:17
Record Number:CaltechAUTHORS:20110929-140501977
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Official Citation:Linear Rheological Response of a Series of Densely Branched Brush Polymers Miao Hu, Yan Xia, Gregory B. McKenna, Julia A. Kornfield and ,Robert H. Grubbs Macromolecules 2011 44 (17), 6935-6943
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:25500
Deposited By: Ruth Sustaita
Deposited On:30 Sep 2011 14:50
Last Modified:09 Mar 2020 13:19

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