The silicone elastomer MPs were by far the largest particle sizes, with the greatest length, area and volume average of all samples (fig. ). The polyolefin MPs show distinct shape characteristics which arise due to their engineered chemical-mechanical properties. LDPE polymers are more branched than their HDPE counterparts, which hinders their crystallization making them more ductile, even below their T g . PP can be considered as having properties in between HDPE and LDPE. It is highly branched, having a methyl group at every monomer unit which allows chains to slide and so imparts a greater ductility than HDPE. However, the small and highly regular size of this group compared to the larger, randomly-distributed side chains of LDPE allows it to form crystalline regions which impart rigidity and brittleness to the material.