So often people want to understand how the thickness of polyethylene is measured. In this article we will touch on the density of polyethylene. Much of the Global Plastic Sheeting website is dedicated to a wide variety of polyethylene such as high density polyethylene, low density polyethylene and the like. How is the density of these plastics measured? The density of polyethylene is expressed as g/cm³. This is how the industry distinguishes between the various grades of poly discussed above. The variation comes from the differences in crystallization structure that forms during polymerization of ethene.
LDPE (Low Density polyethylene) had a density range of 0.910 to 0.940 g/cm³.
HDPE (High Density Polyethylene) has a density of greater or equal to 0.941 g/cm3.
MDPE (Medium Density Polyethylene) is defined by a density range of 0.926 - 0.940 g/cm3.
LLDPE (Linear-Low Density Polyethylene) is defined by a density range of 0.915 - 0.925 g/cm3.
What is fascinating is how close the densities actually are to each other, yet each form of polyethylene has unqiue characteristics.