COMPARING THE EFFECT OF CORONA TREATMENT AND BLOCK-COPOLYMER ADDITION ON RHEOLOGICAL PROPERTIES OF POLYSTYRENE POLYETHYLENE BLENDS

The effect of corona treatment and copolymer modification on linear viscoelastic properties of PS/PE blends in the molten state has been investigated. The results show that corona treatment has little effect on rheological properties of the blends. On the other hand, SEBS addition results in an appreciable decrease of the elastic modulus in the low-frequency region and in a more evident secondary plateau. The data have been analyzed quantitatively by Palierne's emulsion model, which takes into account the presence of an emulsifier agent. The model has been used to estimate the interfacial tension in PS/PE blends as modified by corona treatment and by SEBS copolymer modification. Addition of as little as 1 wt % copolymer resulted in a fivefold decrease of interfacial tension, whereas only a little change was observed in the case of corona modified blends. Further, corona treatment did not affect the size of the dispersed particles, whereas 1 wt % SEBS addition reduced the particle size of the dispersed phase by a factor of 5. Experiments as well as simulations also have been carried out to examine the individual effects of viscosity ratio, particle size distribution, and interfacial tension on dynamic moduli of the blends. © 1995, The Society of Rheology. All rights reserved.