Effect of addition of multifunctional monomers on one-step reactive extrusion of PP/PS blends

One-step reactive compatibilization of PP/PS alloys was studied by using a twin-screw extruder in the presence of dicumyl peroxide (DCP). Compared with mechanical extrusion, reactive extrusion greatly reduced the average dispersed particle size, due to the formation of PP–g–PS graft copolymers, which behave as in situ formed compatibilizers. In order to suppress the degradation of the PP chain during the process, some multifunctional monomers such as GTL, TMPTA, DEGDA, TPGDA were added in combination with DCP. By studying the effect of the monomers on the MFR and the morphology of the resulted blends, it is found that the flexibility of the additive molecules and the reactivity of the double bond of carbon contained in the molecule are crucial for the grafting reaction. The suppression of PP degradation depends on a certain amount of double bonds.