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How Are HDPE, LDPE, and LLDPE Differentiated?

Polyethylene, abbreviated as PE, is one of the most popular and widely used plastic types. Various types of plastic bags are manufactured using polyethylene owing to the flexibility and thickness it offers. Polyethylene is polyolefin made from the polymerization of ethylene gas. Polyolefins are high molecular weight hydrocarbons, which include high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene copolymer and more. These are only the type of plastics with lower specific gravity than water. They are sensitive to UV light and oxidization. However, some form of plastic materials including linear low-density polyethylene (LLDPE) are resistant to UV light, oxidization, and other natural and environmental strains. This post describes how these polyethylene types differ from each other.

Exact Difference between HDPE, LDPE, and LLDPE Plastic Bag Materials

When ethylene is polymerized it results in fairly straight polymer chains, which are branched out from the main chain depending upon the degree of branching in their molecular structure. Here is how polyethylene types differ from each other in terms of physical and chemical properties:

  • Chemical Structures: LDPE is generated from free radical polymerization, which results in short as well as long branching of chains. This makes them highly ductile, but they have low durability and tensile strength. High-density polyethylene’s polymer chain has less branching. This leads to bonded and densely packed molecules making them more robust, rigid, and durable. LLDPE is more flexible than LDPE and HDPE. This is because it has multiple short branches, which can easily slide against each other without entangling.
  • Densities: LDPE has a low density of 0.91-0.925g/cm3. Unlike LDPE, HDPE has a high density of 0.941-0.965g/cm3. LLDPE has a density of 0.91-0.94g/cm3.
  • Melting Points: Polythene becomes liquid at its melting point. This allows easy injection molding and subsequent recycling of the melting point of LDPE and HDPE varies between 110 and 135 degrees Celsius, whereas LLDPE has a melting point of 122 degrees Celsius.
  • Heat Resistance: LLDPE has the least heat resistance. It experiences a drastic decrease in density when subjected to a temperature beyond 20 degrees Celsius. HDPE, on the other hand, can withstand heat with a temperature of more than 100 degrees Celsius. LLDPE has a superior low-temperature heat-resistance ability.
  • Chemical Resistance: All of these plastic materials have superior resistance to most alcohols, solvents, alkalis, and acids, and low resistance to most selected hydrocarbons.
  • Applications: Each of these polyethylene types offers a unique set of advantages, making them ideal for various industrial applications. LDPE is widely used in light packaging materials such as waterproof carton lining, plastic wraps, and so on. It is also used in computer hardware covers and packaging, wash bottles, and more. HDPE is used in strong packaging materials such as plastic milk bottles, drums, bulk containers, bottle caps for industrial use. Also, it is used in pipes and tubing, plastic chairs and tables. LLDPE is used in extrusion coating applications to protect the content of liquid containers.

While there are many domestic as well as industrial applications of all the above-mentioned types of polyethylene, they are widely used to make poly bags for precise and specific applications. Depending on the requirement, you can make customized polythene bags from light to heavy gauges. Are you in search of specific types of poly bags? If yes, then ensure you source them from a reliable manufacturer and supplier such as ANS Plastics. The company provides LDPE, HDPE, and LLDPE polyethylene bags in various configurations to meet your requirements.