LLDPE,LDPE,HDPE, MDPE, XLPE

LDPE (Low Density Polyethylene) has the most excessive branching. This causes the low density to have a less compact molecular structure, which makes it less dense. It has a density of 0.91-0.925g/cm3.

LLDPE (w Density Polyethylene) has a significant of short branches. Because it has shorter and more branches, its chains can slide against each other upon elongation without becoming entangled, like LPDE, which has long branching chains that would get caught on each other. This gives LLDPE higher tensile strength and impact and puncture resistance than the LDPE. It has a density of 0.91-0.94g/cm3.

MDPE (Medium Density Polyethylene) has a little less branching then the HDPE. It is less notch sensitive than HDPE and has better stress-cracking resistance. It has a density range of 0.926 - 0.94 g/cm3

HDPE (High Density Polyethylene) has minimal branching of its’ polymer chains. Because it is denser and more rigid, and less porous than the LDPE. It has a density of 0.941-0.965g/cm3.

XLPE (Crosslinked Polyethylene) is high density polyethylene that has covalent bonds connecting its polymer chains. These bonds are caused by heat plus chemicals or radiation, and they help form 3-dimensional polymers with high molecular weights. These bonds tie the polymers together and lengthen the polymer chains giving them better sical properties. The molecular structure formed by crosslinking provides superior stress cracking, improved toughness, stiffness, and chemical resistance compared to the HDPE.