Melt Processed Blends of Poly (Styrene-co-acrylonitrile) and Poly (Phenylene Ether) Compatibilized with Polystyrene-b-polybutadiene-b-poly (Methyl Methacrylate) Triblock Terpolymers
Polystyrene-b-polybutadiene-b-poly(methyl methacrylate) triblock terpolymers (SBM) with equal (symmetric) and different (asymmetric) block lengths were used to compatibilize polymer blends based on poly(2,6-dimethyl-1,4-phenylene ether) (PPE) and poly(styrene-co-acrylonitrile) (SAN). First, the rheological behavior of the individual components and their binary mixtures was investigated. Based on the results, samples of PPE, SAN and SBM in weight ratios of 32/48/20 were melt blended and the morphology development during melt processing was investigated. It was found that a raspberry morphology, i.e. dispersion of PPE in SAN with rubbery PB domains at the PPE/SAN interface, could be achieved with a symmetric SBM with under sufficiently high shear rate, while a symmetric SBM with did not yield the desired morphology. Asymmetric SBMs with long PS blocks dissolved in the PPE phase did not display the expected compatibilization effect. In order to obtain a raspberry morphology with asymmetric copolymers it is suggested to pre-blend the SBM with SAN before adding the PPE. Finally it is shown that a commercial PPE containing High Impact Polystyrene (HIPS) as a toughness modifier can be compatibilized with SAN by melt processing using a symmetric SBM triblock terpolymer with
Kirschnick, Thorsten; Gottschalk, Axel; Ott, Harald; Abetz, Volker; Puskas, Judit; and Altstädt, Volker, "Melt Processed Blends of Poly (Styrene-co-acrylonitrile) and Poly (Phenylene Ether) Compatibilized with Polystyrene-b-polybutadiene-b-poly (Methyl Methacrylate) Triblock Terpolymers" (2004). Chemical and Biomolecular Engineering Faculty Research. 533.