Model filled rubber. II. Particle composition dependence of suspension rheology
✍ Scribed by Jianfen J. Cai; Ronald Salovey
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 186 KB
- Volume
- 37
- Category
- Article
- ISSN
- 0887-6266
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✦ Synopsis
Monodisperse size colloidal particles varying in chemical composition were synthesized by emulsifier-free emulsion polymerization. Using a stress-controlled rheometer, the rheological behavior of colloidal suspensions in a low molecular weight liquid polysulfide was investigated. All suspensions exhibited shear thinning behavior. The shear viscosity, dynamic moduli, and yield stress increased as interactions between particles and matrix increased. The rheological properties associated with network buildup in the suspensions were sensitively monitored by a kinetic recovery experiment. We propose that interfacial interactions by polar and hydrogen bonding between particles and matrix strongly promote affinity of matrix polymer to the filler particles, resulting in adsorption or entanglement of polymer chains on the filler surface. A network structure was formed consisting of particles with an immobilized polymer layer on the particle surface with each particle floc acting as a temporary physical crosslinking site. As the interfacial interaction increases, the adsorbed layer thickness on the filler particles, hence, the effective particle volume fraction, increases. As a result, the rheological properties were enhanced in the order PS Ͻ PMMA Ͻ PSVP.