Pongsak Pulchuai. A study of phase morphology and mechanical properties of immiscible blends . Master's Degree(Polymer Science and Technology). Mahidol University. : Mahidol University, 2004.
A study of phase morphology and mechanical properties of immiscible blends
Abstract:
This research focused on the blends of polypropylene with either polystyrene or
ethylene-octene copolymer. The effects of blend composition, viscosity ratio and
interfacial tension between phases as well as processing procedure on the morphology
and mechanical properties of polymer blends were investigated. The blend
morphology was studied both qualitatively and quantitatively. Some selected theories
were used for the explanation of morphological results. The blends were also
characterised for their mechanical tensile and impact properties. The relationships
between blend morphology and mechanical properties were drawn.
All blends in this study showed polydisperse behaviour, whereby the calculated
particle size distribution parameter was greater than unity. The average particle size
and size distribution increased with an increase in the content of the dispersed
components. Conversely, the matrix ligament thickness, i.e., the surface-to-surface
interparticle distance between the two nearest neighbours, was found to have a
negative correlation with the particle size result obtained in this study. The blend
morphology generated during compounding in an extruder was found unstable but
changed upon reprocessing in an injection moulding machine. Tensile properties
seemed to depend only on the concentrations and properties of the dispersed
components in the blends, while impact strength was governed more by the
morphology of the blends