Determining the Dilution Exponent for Entangled 1,4-Polybutadienes Using Blends of Near-Monodisperse Star with Unentangled, Low Molecular Weight Linear Polymers
Type
ArticleAuthors
Hall, RyanKang, Beom-Goo
Lee, Sanghoon
Chang, Taihyun
Venerus, David C.
Hadjichristidis, Nikos

Mays, Jimmy
Larson, Ronald G.
KAUST Department
Chemical Science ProgramKAUST Catalysis Center (KCC)
Physical Science and Engineering (PSE) Division
Polymer Synthesis Laboratory
Date
2019-02-11Online Publication Date
2019-02-11Print Publication Date
2019-02-26Permanent link to this record
http://hdl.handle.net/10754/631840
Metadata
Show full item recordAbstract
We determine experimentally the “dilution exponent” α for entangled polymers from the scaling of terminal crossover frequency with entanglement density from the linear rheology of three 1,4-polybutadiene star polymers that are blended with low-molecular-weight, unentangled linear 1,4-polybutadiene at various star volume fractions, ϕs. Assuming that the rheology of monodisperse stars depends solely on the plateau modulus GN(ϕs) ∝ ϕs1+α, the number of entanglements per chain Me(ϕs) ∝ ϕs–α, and the tube-segment frictional Rouse time τe(ϕs) ∝ ϕs–2α, we show that only an α = 1 scaling superposes the Me(ϕs) dependence of the terminal crossover frequency ωx,t of the blends with those of pure stars, not α = 4/3. This is the first determination of α for star polymers that does not rely on any particular tube model implementation. We also show that a generalized tube model, the “Hierarchical model”, using the “Das” parameter set with α = 1 reasonably predicts the rheological data of the melts and blends featured in this paper.Citation
Hall R, Kang B-G, Lee S, Chang T, Venerus DC, et al. (2019) Determining the Dilution Exponent for Entangled 1,4-Polybutadienes Using Blends of Near-Monodisperse Star with Unentangled, Low Molecular Weight Linear Polymers. Macromolecules 52: 1757–1771. Available: http://dx.doi.org/10.1021/acs.macromol.8b01828.Sponsors
R.H. and R.G.L. gratefully acknowledge the support of the National Science Foundation under Grants DMR 1403335 and 1707640. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation (NSF). N.H. gratefully acknowledges the support of the King Abdullah University of Science and Technology (KAUST).Publisher
American Chemical Society (ACS)Journal
MacromoleculesAdditional Links
https://pubs.acs.org/doi/10.1021/acs.macromol.8b01828ae974a485f413a2113503eed53cd6c53
10.1021/acs.macromol.8b01828