:class=skin-invert-image|thumb|The branched structure of LDPE.

Low-density polyethylene (LDPE) is one of several varieties of polyethylene (PE). A variety of LDPE's are known, which mainly differ by the degree of linearity vs branching.

LDPE can be further classified: LDPE and linear low-density PE. The former is produced by free-radical polymerization and the latter by coordination polymerization (e.g. Ziegler-Natta catalysis.

Properties

LDPE is a thermoplastic. PE's are often classified by their densities.

{| class="wikitable"

|+ Polyethylene (PE) densities and structure

Applications

thumb|A GEECO bowl, c.1950, still used in 2014

thumb|A piece of [[Cushioning|packaging foam made from LDPE]]

thumb|A Ziploc bag made from LDPE

thumb|Facial wash gel bottle made of LDPE

Polyolefins (LDPE, HDPE, PP) are a major type of thermoplastic. LDPE is widely used for manufacturing various containers, dispensing bottles, wash bottles, tubing, plastic parts for computer components, and various molded laboratory equipment.<!-- and many more, care to add? --> Its most common use is in plastic bags. Other products made from it include:

  • Trays and general purpose containers
  • Corrosion-resistant work surfaces
  • Parts that need to be weldable and machinable
  • Parts that require flexibility, for which it serves very well
  • Very soft and pliable parts such as snap-on lids
  • Six-pack rings
  • Juice and milk cartons are made of liquid packaging board, a laminate of paperboard and LDPE (as the waterproof inner and outer layer), and often with of a layer of aluminum foil (thus becoming aseptic packaging).
  • Packaging for computer hardware, such as hard disk drives, screen cards, and optical disc drives
  • Playground slides
  • Plastic wraps
  • Plastic bags
  • Plastic containers
  • Pipes
  • Housewares
  • Battery cases
  • Automotive parts
  • Electrical components Major innovations were made in the 1950 by commercial, governmental, and university labs, focusing especially on catalysts, which allowed the production of PE without free radicals. Some of this work led to the Nobel Prize in Chemistry. Despite its designation with the recycling symbol, it cannot be as commonly recycled as No. 1 (polyethylene terephthalate) or 2 plastics (high-density polyethylene).

See also

  • Film blowing machine
  • High-density polyethylene (HDPE)
  • Linear low-density polyethylene (LLDPE)
  • Medium-density polyethylene (MDPE)
  • Polyethylene terephthalate (PET/PETE)
  • Stretch wrap
  • Ultra-high-molecular-weight polyethylene (UHMWPE)

References

  • 2010_MSW_Tables_and_Figures_508.pdf. epa.gov