Low-Density Polyethylene and High-Density Polyethylene are both forms of plastics that are created from Polyethylene. Polyethylene is a thermoplastic that is created by polymerizing ethylene and the different processes then create either Low Density or High Density Polyethylene.
LDPE has a more linear molecule structure. The layout of the molecules are in a straight line with the same chains branching off in different directions. This very linear and branched molecular chain allows the chains to bend more and there are also much larger spaces between the molecule chains. This means that the polyethylene is much softer and flexible and is used or products like plastic hoses, LDPE pipes, plastic packaging, basins etc.
HDPE has a more crystalline and solid structure. The layout of the molecules are more organized line by line and row by row and column by column. This provides much stronger bonds, less open space and tighter layouts. This organized and crystalline structure makes stronger plastics that are more rugged and less flexible. HDPE plastics are more often used for PVC Piping, crates, buckets, and HDPE Pipes. These HDPE products are often used for more rugged jobs like containers, jugs, crates, plastic outdoor chairs and heavy-duty usage.
Both LDPE and HDPE are low cost to produce, weather proof, have varied levels of chemical resistance, and can handle compression well. Aside from the molecular difference, HDPE and LDPE have many of the same similarities even if HDPE is slightly more resistant and stronger than LDPE. Both LDPE and HDPE are used in hydraulics, with HDPE used in fluid feeds, drains, portable water systems, and beverage and food processing while LDPE are used for compression plugs. HDPE, because it is semi rigid, is perfect for tubing with push to connect fittings without clamps and works great with low pressure pneumatic systems.
In the Automotive Industry, HDPE and LDPE is used for a variety of materials. HDPE is used In the production of fuel tanks and accounts for a total of 44% of plastic in fuel systems. The reason for this is that HDPE is ideal for blow molding, giving tanks excellent performance. HDPE is also used in the manufacturing of car bodies as the light yet strong material aides in making vehicles more fuel efficient. LDPE is used for exterior light weight parts for vehicles. Connector caps are for example made out of LDPE as many connectors and covers must be able to bend and contour when under pressure.
Packaging is used world wide and is used to contain and transport most of the things we use day to day. Some objects, tools, devices and components must be transported with some more protection. Both LDPE and HDPE packaging is cheap and cost effective to produce. LDPE packaging is used where heat sealing is products is needed. LDPE is used for flexible lids and bottles. HDPE is used well with products that have a very short shelf life.
