*Polyethylenes: A Vital Recyclable Polymer DOI: http://dx.doi.org/10.5772/intechopen.102836*


#### **Table 2.**

*Effects of density, molecular weight and molecular weight distribution on some properties of polyethylene [14].*

0.33Wm−1 K−1, melting point (MP) 109–125°C for low-density polyethylene and 130–135°C for high-density polyethylene. The specific gravity of LDPE is between 0.915–0.94, while that of HDPE is 0.94–0.97. PE has a refractive index of 1.51–1.52. PE also has excellent electrical properties. Its electrical resistivity is 1017–1019 ohm-m, dielectric strength 20 kV–160 kV/mm, and dielectric constant of 2.28. Polyethylenes, when exposed to moisture for 1 year, increase their weight by 0.2%. This shows excellent water resistance. PE's average elastic modulus is between 0.565–1.500GPa for HDPE and 0.190–0.520GPa for LDPE, flexural modulus is between 0.28–1.86GPa for HDPE and 0.152–2.200GPa for LDPE. It also has Flexural yield strength of 13.8–75.8 MPa, compressive yield strength of 4 MPa-23 MPa for HDPE, and Tensile strength (TS) at yield is 7 MPa-16 MPa and that at the break at 23°C is 32 MPa-60 MPa for LDPE. LDPE has a hardness of 50–60 while its HDPE counterpart is 65–70 with an impact of 0.92 for LDPE and 0.96 for HDPE [16].
