Difference Between Low-density polythene LDPE and High-density polythene HDPE

Difference Between Low-density polythene LDPE and High-density polythene HDPE

High-density polythene is a linear polymer, i.e., consisting of long and straight chains while low-density polythene is a branched chain polymer, i.e., contains linear chains having some branches. One of the key differences between high density vs low density can liners is the sound and feel. High-density bags or can liners will have a more stiff feeling and sound "crunchier." In contrast, low-density polyethylene bags will be much quieter to the touch and have a softer feel

HDPE has higher abrasion and tears resistance than LDPE, along with higher tensile and shear strength. If you're going to bury your cables underground, then opt for HDPE. Otherwise, LDPE is an excellent choice. LDPE cable conduits give you outstanding flexibility, high fatigue life, and high-impact strength. High-density polyethylene and low-density polyethylene are two common polyethylenes with differing structures but similar properties. HDPE has a linear structure and is opaque, while LDPE is a transparent branched version of PE.

HDPE's structure is crystalline. HDPE's formidable structure gives it a higher density than LDPE. The forces of attraction between polymer molecules are strong. As its name suggests, low-density polyethylene (LDPE) has a lower density, strength, and temperature resistance. Meanwhile, high-density polyethylene (HDPE) is characterized by higher specific strength and heat resistance.

High-density polythene HDPE

High-density polyethylene or polyethylene high-density is a thermoplastic polymer produced from monomer ethylene. It is sometimes called "alkaline" or "polythene" when used for HDPE pipes.

High-Density Poly Ethylene (HDPE) is a petroleum-based thermoplastic polymer considered one of the most versatile plastic materials available today. It is used to manufacture numerous items, including food and beverage containers, cleaning product bottles, pipes, cutting boards, and some shoe parts.

High-density polyethylene, or HDPE. Most milk jugs, detergent and juice bottles, butter tubs, and toiletries containers are made of HDPE. Usually opaque in color, this plastic is considered safe and has a low risk of leaching. It is picked up by most recycling programs.

HDPE is a type of polyethylene, the most common plastic which accounts for over 34% of the global plastic market. It is a polymer made up of a huge number of repeating units (known as monomers), and its chemical formula can be generalized as (C2H4)n. The branching in high-density polyethylene is of a relatively low degree (when compared to other categories of polyethylene). The general structure of HDPE is illustrated below.

HDPE is used to make bottles for fruit juice, milk, water, kitchen cleaning products, and even furniture. It has been used in recent years for garden furniture as it resists the weather and can be cleaned very easily. It is lightweight which means furniture made from this material can be handled and transported very easily. It is an ideal material for the injection molding process making it suitable for batch and continuous production. It has the following properties: Stiffness, strength, toughness, resistance to chemicals and moisture, permeability to gas, ease of processing, and ease of forming.


  • The temperature and pressure required for the formation of high-density polythene are 333K-343K and 6-7 atmospheres respectively.
  • Catalysts are triethylaluminium and titanium tetrachloride (Ziegler-Natta catalyst).
  • It has a linear structure and high density due to close packing, that is why it is also called a linear polymer.
  • Are chemically inert, more tough but hard.
  • Used in manufacturing buckets, bottles, and dustbins.
  • Can resist high temperatures.
  • Have stronger intermolecular forces.

 Low-density polythene LDPE 

Low-density polyethylene (LDPE) is a thermoplastic made from monomer ethylene. It was the first grade of polyethylene, produced in 1933 by Imperial Chemical Industries (ICI) using a high-pressure process via free radical polymerization. Its manufacture employs the same method today.

Low-Density Polyethylene (LDPE) uses majorly revolve around manufacturing containers, dispensing bottles, wash bottles, tubing, plastic bags for computer components, and various molded laboratory types of equipment. The most popular application of low-density polyethylene is plastic bags. With LDPE, there is a high degree of branching, which means that the polymer has a less compact molecular structure leading to a lower density and greater flexibility.

Low-density polyethylene has a good balance of flexibility, strength, barrier properties, and cost and can have a wide combination of properties. Low-density polyethylene has high clarity, is chemically inert, and has good impact strength and excellent tear and stress crack resistance.

Low-density polyethylene (LDPE). This clear or translucent plastic exhibits flexibility, chemical resistance, and waterproofing capabilities. It is used in the manufacture of a wide range of products, including grocery bags, plastic wrap and film, flexible packaging material, and injection molded parts.


  • The temperature and pressure required for the formation of low-density polythene are 350K to 570K and 1000 atmosphere to 2000 atmosphere respectively.
  • The catalyst required is a peroxide initiator or traces of dioxygen.
  • It has a highly branched structure.
  • Are chemically inert, and tough but flexible.
  • Used in the insulation of electric wires and in the manufacturing toys and pipes.
  • Cannot resist high temperature.
  • Have weaker intermolecular forces.

Properties of Low-density polythene LDPE

  • It is a homopolymer; made of a single monomer, ethylene.
  • The polymer density is controlled by the kind of branching it has.
  • LDPE contains a mix of long branched chains and short branched chains.
  • It is produced by undergoing a high-pressure process.
  • LDPE is characterized by 50-65% crystallinity, as the packing of the molecules is not the tightest.
  • It is translucent in appearance, as a result of the crystallinity. However, very thin foils can be transparent.
  • It is not very easy to bond.
  • LDPE is sufficiently malleable and elastic, able to undergo significant elongation before breakage.
  • It is fairly puncture-resistant, between -40 C to 90 C.
  • LDPE is susceptible to stress-cracking beyond a point.
  • It has a sufficient moisture barrier.
  • Its oxygen barrier is low.
  • It has significant chemical resistance.
  • It is a flammable material.
  • LDPE softens at a relatively low temperature of approximately 100°C. In fact, for some grades, the temperature could be even lower.
  • It undergoes high thermal expansion.
  • Its weathering resistance is not very good.
  • ItS processing can easily take place by practically all thermoplastic methods.
  • It has food grades available as well.

LDPE Applications 

  • LDPE plastic bags
  • Light packaging materials: Six-pack rings, waterproof carton lining, plastic wraps, snap-on lids
  • Wash bottles
  • Corrosion protection layer for work surfaces
  • Computer hardware covers and packaging

HDPE Applications

  • HDPE filament for 3D printers
  • Strong packaging materials: bottle caps, plastic milk bottles, drums, bulk containers for industrial use
  • Fibers for ropes, nets, and industrial fabrics
  • Vehicle fuel tanks
  • Boat parts
  • HDPE pipes and tubing
  • HDPE plastic chairs and tables
  • Playground structures: slides, swing seats
  • Consumer products: trash and recycling bins, ice cube containers, toys, ice chests




Semi-rigid; tough

Good compression set

Good compression set

Good abrasion resistance

Excellent abrasion resistance



Good chemical resistance (variable(

Good chemical resistance (variable)



Low cost

Low cost

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