Difference Between HDPE and LDPE

Key Difference – HDPE vs LDPE

Though HDPE and LDPE are two categories of Polyethylene, some differences can be observed between them based on their mechanical properties. Polyethylene is a mixture of similar organic compounds which have the chemical formula of (C2H4)n. Polyethylene is categorized into numerous different groups based mainly on its density and branching. With regard to demands and supply, the most important polyethylene grades are HDPE and LDPE. The High-density Polyethylene (HDPE) and Low-density Polyethylene (LDPE) have different mechanical properties such as the crystal structure, the magnitude and nature of branching and the molecular weight. In other words, HDPE and LDPE are considered as the contrasting ends of the plastics applications spectrum.  The key difference between HDPE and LDPE is the density or the manner in which the polymer molecules align. HDPE polymers are straighter and closely packed together whereas LDPE polymers have lots of branches, and they are not closely packed. Based on the molecular structure each type of plastic has its own physical and chemical characteristics. In this article, let’s elaborate what are the differences between HDPE and LDPE.

What is High Density Polyethylene (HDPE)?

HDPE is well-defined by a density of larger or equal to 0.941 g/cm3. It has a liner polymer and lower degree of branching. This  results in molecules to be packed closer and intermolecular bonds are stronger than in highly branched polymers such as LDPE. The ABSence of branching also results in a higher density and somewhat higher chemical resistance than LDPE. With a high tensile strength, HDPE is used in products like garbage containers, baby toys, water pipes, jugs and jars as well as packagings such as milk jugs, butter tubs, and detergent bottles. HDPE is also more durable and more opaque and can tolerate higher temperatures mainly compared to LDPE. Industrially, HDPE is synthesized from ethylene by a catalytic procedure.

What is Low Density Polyethylene (LDPE)?

LDPE is well-defined by a density range of 0.91–0.94g/cm3. A branched polymer, LDPE is synthesized from ethylene by a catalytic procedure. The more branching nature results in molecules packing irregularly and intermolecular bonds are weaker than in highly linear polymers such as HDPE. With a low tensile strength, LDPE is used in products like plastic bags and film wrap as well as packagings such as water bottles, food storage containers, dispensing bottles and plastic tubs. LDPE is also more flexible and more transparent and cannot tolerate higher temperatures mainly compared to HDPE.

If you have questions or concerns regarding your part or LDPE, HDPE, contact our experts at Sunring Industry today!