Yunwa W. Cheung

- Blends of Ethylene/Styrene Interpolymers and Other Polymers: Benefits in Applications

INSITE™ technology has enabled the synthesis of ethylene/styrene interpolymers (ESI) using single site constrained geometry catalysts. The current focus is on ESI containing up to about 50 mole % (∼ 80 wt%) copolymer styrene content. These ESIs encompass materials ranging from crystalline to amorphous microstructure, dependent upon the copolymer styrene content. Materials engineering through blending of ESIs with other thermoplastic polymers can be used to expand the material performance envelope, and design materials to meet specific performance requirements. The performance requirements of potential applications currently under development for ESI can be met by thermoplastic blends with one or more thermoplastic polymers. ESIs exhibit compatibility with a wide range of polymers because of their inherent combination of olefinic and styrenic functionality. Blends of ESI with PS, PE, and PP, in particular, have been found to offer interesting and unique combinations of performance properties. The selection of blend components, blend composition ratio and final part fabrication conditions are key factors in determining structure/property relationships. Appropriate morphology/rheology modeling is useful in blend design.

Melt Rheology and Processability of Ethylene/Styrene Interpolymers

The melt rheology and processing characteristics of ethylene/styrene interpolymers, ESI, are correlated with the styrene content and molecular weight of the interpolymers. The complex viscosity, mastercurves, activation energy, high shear rate processability, and melt strength are discussed for four well-defined ESI. Comparisons are also made to polyethylene and polystyrene where appropriate.