The Role of Thermodynamic Parameters and Mixing Kinetics in Determining the Morphology of Nanosilica Containing Ternary Blends: with Emphasize on Core-Shell Morphology

The core-shell morphology development in ternary blends is significantly controlled by thermodynamic parameters including spreading coefficient. In the present work, an attempt was made to study the influence of hydrophobic nanosilica on morphology development of HDPE/PS/PMMA(80/7/13 wt%) ternary blend in which PMMA was encapsulated by PS shell dispersed in HDPE matrix. The melt linear viscoelastic results obtained from oscillatory tests exhibited a slightly greater low frequency non-terminal storage modulus compared to binary samples. This could be related to core-shell type morphology of the ternary blend samples. Thiswas evidenced by the SEM micrographs of the samples in which PS shell was etched out. Theresults of melt rheological measurements together with the results of SEM performed on the binary and ternary nanocomposite systems showed that the effect of nanosilica on core-shellmorphology is highly dependent upon the sequence of feeding. In most of the samples prepared by different feeding order retained their core-shell morphology, while nanosilica had a deteriorating effect on core-shell morphology on the samples in which PS was first compoundedwith nanosilica and then melted with other blend components. These results could be explainedin terms of affinity between the nanosilica and blend components on one hand and the mixing time on the other hand.

کلیدواژه ها:

Ternary polymer blend ، Rheology ، Viscoelastic properties ، Nanosilica