Paper Number
PO86 

Session
Poster Session

Title
Shear thinning and thickening behaviors of hollow carbon nanoparticles in Newtonian fluids

Presentation Date and Time
October 23, 2019 (Wednesday) 6:30

Track / Room
Poster Session / Ballroom C on 4th floor

Authors (Click on name to view author profile)

1. Kiany, Parvin (Amirkabir University of Technology, Polymer Engineering)
2. Goharpey, Fatemeh (Amirkabir University of Technology, Polymer Engineering)
3. Foudazi, Reza (New Mexico State University, Department of Chemical and Materials Engineering)

Author and Affiliation Lines (in printed abstract book)
Parvin Kiany¹, Fatemeh Goharpey¹, and Reza Foudazi^2
1Polymer Engineering, Amirkabir University of Technology, Tehran, Iran; ²Department of Chemical and Materials Engineering, New Mexico State University, Las Cruces, NM 88003

Speaker / Presenter 
Goharpey, Fatemeh

Text of Abstract
We investigated the rheological properties of hollow carbon spheres (HCSs) suspended in polyethylene glycol (PEG-400) at different volume fractions. The viscosity increases and the shear thinning behavior intensifies with volume fraction. At 12 vol% of HCSs, with increasing the shear rate, shear thinning is followed by shear thickening and a secondary shear thinning. This behavior can be attributed to the aggregation of HCSs due to their attractive surface (their zeta potential is lower than 30 mV). Based on Krieger-Dougherty equation, the maximum packing volume fraction of HCSs is about 0.53. Under weak shear, negative normal stress differences are observed, which can be attributed to the alignment of aggregates. When hybrids of bowl-like and spherical particles are used, the shear thickening behavior is diminished in the studied experimental shear rate range.