A high impact polypropylene / high density polyethylene 80/20 blend was compatibilized by incorporating 5wt% of different metallocene random copolymers ethylene-α-olefin (mPE). The comonomer (butene or octene) content is ranged from 8.3 to 19.2 wt%. In some cases, a great improvement of mechanical properties was obtained due to a better interfacial adhesion. For example, elongation at break could increase from 60 to 340%.
The comonomer content has a strong effect on these results. On the contrary, viscosity, comonomer type or molecular weight are not influent parameters. The presence of 22wt% of EPR in high impact polypropylene has also a great impact on performances. EPR and metallocene copolymer are miscible.