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Small and Medium Amplitude Oscillatory Shear Rheology of Model Branched Polystyrene (PS) Melts

Song, Hyeong Yong; Faust, Lorenz; Son, Jinha; Kim, Mingeun; Park, Seung Joon; Ahn, Suk-kyun; Wilhelm, Manfred; Hyun, Kyu

Abstract:
Linear and nonlinear rheological properties of model comb polystyrenes (PS) with loosely to densely grafted architectures were measured under small and medium amplitude oscillatory shear (SAOS and MAOS) flow. This comb PS set had the same length of backbone and branches but varied in the number of branches from 3 to 120 branches. Linear viscoelastic properties of the comb PS were compared with the hierarchical model predictions. The model underpredicted zero-shear viscosity and backbone plateau modulus of densely branched comb with 60 or 120 branches because the model does not include the effect of side chain crowding. First- and third-harmonic nonlinearities reflected the hierarchy in the relaxation motion of comb structures. Notably, the low-frequency plateau values of first-harmonic MAOS moduli scaled with M$^{-2}$$_{w}$ (total molecular weight), reflecting dynamic tube dilution (DTD) by relaxed branches. Relative intrinsic nonlinearity Q$_{0}$ exhibited the difference between comb and bottlebrush via no low-frequency Q$_{0}$ peak of bottlebrush corresponding to backbone relaxation, which is probably related to the stretched backbone conformation in bottlebrush.

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Verlagsausgabe §
DOI: 10.5445/IR/1000118773
Veröffentlicht am 28.04.2020
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Technische Chemie und Polymerchemie (ITCP)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 02.2020
Sprache Englisch
Identifikator ISSN: 2073-4360
KITopen-ID: 1000118773
Erschienen in Polymers
Band 12
Heft 2
Seiten Art. Nr.: 365
Vorab online veröffentlicht am 07.02.2020
Schlagwörter comb polymer, Bottlebrush polymer, medium amplitude oscillatory shear (MAOS), FT rheology, nonlinear parameter
Nachgewiesen in Scopus
Web of Science
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