Polyethylene is a general purpose or commodity thermoplastic that is characterized along side with Polypropylene in the Olefin family.
PE has the highest annual production volume of all plastics due to its low cost. PE has a low specific gravity of approximately 0.95 g/cc but changes slightly with the different characterizations of Polyethylene. PE is a family of material that range from Low Density Polyethylene, (LDPE), to Medium Density Polyethylene, (MDPE), to High Density Polyethylene, (HDPE), all the way to Ultra High Molecular Weight Polyethylene, (UHMWPE).
PE’s high crystallinity account for it’s relatively high melting point, (ranging from 110 degrees Celsius for LDPE to 138 degrees Celsius for HDPE), its good chemical resistance, and its high translucency.
The crystalline structures disrupt light transmission through the matrix and destroy clarity. PE has a low glass-transition temperature of -120 degrees Celsius, therefore it is relatively flexible at room temperature, giving it good toughness and impact resistance.
PE has relatively low tensile strength, and poor UV-resistance. If the intended application requires extended sunlight exposure, weatherability agents can be added to improve the polymer’s resistance to UV-light.
Proper selection of a grade of polyethylene resin for use in applications is based off three important properties: density, melt index, and molecular weight distribution, so be sure to consult with out experts to help you find the best solution for your product.