The effect of polymer-induced attraction on dynamical arrests of polymer composites with bimodal particle size distributions
- Univ. of Illinois at Urbana-Champaign, IL (United States); 3M Corporate R&D, Maplewood, MN (United States); University of Illinois
- Univ. of Illinois at Urbana-Champaign, IL (United States); Univ. at Buffalo, NY (United States)
We explore the flow properties of nanocomposite melts where the particles have bimodal size distributions and experience a weak attraction produced by suspending silica particles in polyethylene glycol melts with a molecular weight of 2000 (PEG2000). The polymer is unentangled and adsorbs to the particle surface. Here, the volume fraction ratio of large particles to total particle volume fraction, R, is systematically varied to study the effects of this polymer-induced attraction on suspension rheology. The maximum volume fraction, Φm, of the particles varies in a nonmonotonic manner of R as demonstrated in studies of the same mixtures when suspended in polyethylene glycol with a molecular weight of 400 (PEG400), where the particles experience excluded volume interactions. The dynamical arrest volume fraction Φx, of nanocomposite melts in PEG2000 monotonically increases with R. In frequency sweep experiments, the plateau elastic modulus is dominated by attractive interactions and increases with the total particle volume fraction, Φc, proportionally with 1/(h2< D >), where < D > is the volume average particle diameter and h is the average particle-particle surface separation. As R is varied, this universal yielding behavior occurs at constant surface separation, h, suggesting that the flow properties of the mixtures can be understood as being equivalent to flow properties of homogeneous particle suspensions experiencing short-range attractions with an extent independent of particle size.
- Research Organization:
- Univ. of Illinois at Urbana-Champaign, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division
- Grant/Contract Number:
- FG02-07ER46453; FG02-07ER46471
- OSTI ID:
- 1876425
- Journal Information:
- Journal of Rheology, Journal Name: Journal of Rheology Journal Issue: 6 Vol. 57; ISSN 0148-6055
- Publisher:
- Society of RheologyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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