pps proceeding - Abstract Preview
pps proceeding
Symposium: S10 - Rheology and Rheometry
Poster Presentation
 
 

A comparative study on structural recovery of nanoparticles after cessation ofsteady shear flow: the effect of nanoparticle flexibility

ranjbar behnaz (1), Ghıassınejad Sına (1), Nazockdast Hosseın (1)*

(1) am& - 305;rkab& - 305;r un& - 305;ves& - 305;ty of technology - tehran - Iran

The aim of the present work was to study the effect of nanoparticle flexibility onincreasing the storage modulus after cessation of shear flow field. For thispurpose polyethylene oxide (PEO) was utilized as a matrix and multi-walledcarbon nanotube (MWCNT) and cloisite 30B were used as the nanoparticles thesamples above percolation threshold were pre-sheared at different shearrates/times. Then the shear was stopped and the re-structuring was monitoredas a function of rest time. In order to better understanding of structuralrecovery process, the structure parameter evolution was calculated as afunction of time. The first time derivative of structure parameter showed thatdisorientation process for MWCNT containing nanocomposite samples weredone within two steps, where the first step was carried out faster. While, for thecloisite 30B containing nanocomposite samples, the structural recovery wascarried out in one step. We proposed a physical model for these processes andfinally we related the change in the rate of recovery in MWCNT containingnanocomposite samples to the two governing mechanisms for structurerecovery and nanoparticle disorientation.