INTRODUCTION TO HDPE
Polyethylene is the most popular plastic in the world. It has a very simple structure, the simplest of all commercial polymers. A molecule of polyethylene is a long chain of carbon atoms, with two hydrogen atoms attached to each carbon atom.
Sometimes it is a little more complicated. Sometimes some of the carbons, instead of having hydrogen attached to them, will have long chains of polyethylene attached to them. This is called branched, or low-density polyethylene, or LDPE.
When there is no branching, it is called linear polyethylene, or HDPE, short for high density polyethylene. Linear polyethylene is much stringer than branched polyethylene, but branched polyethylene is cheaper and easier to make.
As a result of branching, side groups become attached to the main chain. Branching leads to a decrease in crystallinity, lowered density, and impaired stiffness. Branched, low-density polyethylene has good toughness and pliability. It has outstanding electrical properties, it is resistant to acids and bases, and has high tear strength. Branched polyethylene is used for films, drapes, table cloths, squeeze bottles, and coatings for foil.
Linear, high-density polyethylene has high crystallinity and high melting temperature. Linear polyethylene has a greater hardness and tensile strength than branched polyethylene. It is used in bottles, house wares, toys, pipes, and wire and cable insulation.