Compatibilizing Effect of Poly(Styrene-block-2-Vinylpyridine) Copolymer on Polystyrene/Ethylene-Based Ionomer Resin Blends

Abstract

The effect of adding the diblock copolymer poly(styrene-block-2-vinylpyridine) P(S-b-2VP] to immiscible blends of polystyrene (PS)/ethylene based ionomer resin [zinc salt of poly(ethylene–co–methacrylic acid)] on the morphology, dynamic mechanical, and mechanical properties of the blends has been investigated. The diblock copolymer was synthesized by sequential anionic copolymerization and was melt-blended with PS and ionomer. Scanning electron microscopy (SEM) showed that the added block copolymer reduced the domain size of the dispersed phase in the blends. Dynamic mechanical analysis (DMA) revealed that the extent of compatibility between PS and ionomer affected the values tan δ and glass transition temperature Tg of the blends. Notched impact strength, tensile strength, and elongation at break were determined as a function of different amounts of added P(S-b-2VP) in the blends. The compatibilizing effect of the diblock copolymer is most probably the result of its location at the interface between the PS and the ionomer phases and penetration of the blocks into the corresponding phases, that is, the polystyrene block enters the PS matrix, and the poly(2-vinylpyridine) block interacts with ionomer through ion-ligand interaction.

Keywords:

• blending
• compatibilization
• polystyrene
• ionomer
• diblock copolymer

Acknowledgments

This work was supported by the National Science Foundation of China (Proj. 59373141).