Structure of block PP

Block PP contains PE dispersed in it as shown in the illustration below. There is the EPR phase (rubber phase) around the PE. Because of this structure, the impact strength of block PP is higher than that of homo PP. If homo PP is compared to the sea, PE / EPR looks as if they are islands. For this reason, this structure is sometimes called “island structure”.

It is said that the reason why block copolymer shows higher impact strength than homo polymer is that it is due to the “island structure” of PE / EPR.

Structure of block PP