Branched polymers Brittle fracture

Comonomer content. Because they contain a small amount of comonomer, such as 1-butene or 1-hexene, MDPE and LDPE exhibit short branches that tend to inhibit crystallinity. A higher comonomer concentration results in better brittle fracture resistance, most likely because the portions of polymer chains with the longer branches (for example, 1-hexene or longer) do not... 

---