Polypropylene/polystyrene blends—Preliminary studies for compatibilization by aromatic‐grafted polypropylene

The blends of Polypropylene (PP), that is a semicrystalline and nonpolar thermoplastic polymer with a polar and amorphous polymer such as Polystyrene (PS), are known to be immiscible. This article investigates the use of an aromatic vinyl monomer (AVM)-grafted PP (PPA) as a potential compatibilizer for such an immiscible blend system (PP/PS blend). PPA was prepared by grafting a monofunctional aromatic vinyl monomer onto PP using an organic peroxide at 180°C for 10 min in a Brabender mixer. Using a twin-screw extruder, blends of PP/PS in various composition containing different amount of PPA were prepared. Results obtained from tensile and impact strength, heat deflection, and melt flow index measurements shows some improvement in the properties of the blends indicating some compatibilization effects in the blend system. However, the scanning electron microscopy (SEM) micrographs strongly suggested a significant compatibilization between PP and PS. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 428–434, 2001