Difference between revisions of "Low density polyethylene"

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== Description ==
 
== Description ==
  
A type of [[polyethylene]] composed primarily of long, linear hydrocarbon chains. This produces a tightly packed crystalline polymer with a density greater than 0.94. High density polyethylene (HDPE) is stiffer, harder and less permeable than low density polyethylene. It also has higher tensile strength and lower impact strength. HDPE is used for containers, packaging films, fibers, pipes, and molded pieces. It is also found in toys, bowls, and milk bottle crates.
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The first grade of [[polyethylene]], a thermoplastic polymer composed from the monomer ethylene. Low density polyethylene (LDPE) was produced in 1933 by Imperial Chemical Industries (ICI) using a free radical process that is still used today.  LDPE is weaker, softer and more permeable than high density polyethylene (HDPE). It is also easier to bend, mold and weld into flexible plastics parts that have high impact resistance. LDPE is typically translucent or opaque.
  
 
== Synonyms and Related Terms ==
 
== Synonyms and Related Terms ==
  
HDPE; high-density polyethylene; polietileno de alta densidad (Esp.); polyéthylène haute densité (Fr.); polietilene ad alta densità (It.); polietileno de alta densidade (Port.)
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LDPE; low-density polyethylene; polietileno de baja densidad (Esp.); polyéthylène basse densité (Fr.); polietilene ad bassa densità (It.); polietileno de baixa densidade (Port.)
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==Applications==
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* Plastic bags; recyclable (symbol #4) at some in-store collection locations
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* Parts that need to be welded or molded
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* Trays and general purpose containers
  
 
== Risks ==
 
== Risks ==
 
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* Breaks down in UV light forming methane and ethylene
 
* Dust may cause irritation.   
 
* Dust may cause irritation.   
 
* Susceptible to stress cracking
 
* Susceptible to stress cracking
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==Physical and Chemical Properties==
 
==Physical and Chemical Properties==
  
* For a 1 mil film: Oxygen transmission =1368-4256 ml/m2d    Water vapor transmission = 57-76 g/m2d  
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* For a 1 mil film: Oxygen transmission = 1368-4256 ml/m2d     
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* Water vapor transmission = 57-76 g/m2d
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* Density range of 917-930 kg/m3 
 
* Resistant to most solvents except nitric and hydrochloric acids.  May swell in oil.
 
* Resistant to most solvents except nitric and hydrochloric acids.  May swell in oil.
 
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* Can withstand continuous temperatures of 65C
{| class="wikitable"
 
|-
 
! scope="row"| CAS
 
| 9002-88-4
 
|-
 
! scope="row"| Melting Point
 
| 150 C
 
|-
 
! scope="row"| Density
 
| >0.94 g/ml
 
|}
 
  
 
== Comparisons ==
 
== Comparisons ==

Latest revision as of 12:57, 23 September 2023

Description

The first grade of Polyethylene, a thermoplastic polymer composed from the monomer ethylene. Low density polyethylene (LDPE) was produced in 1933 by Imperial Chemical Industries (ICI) using a free radical process that is still used today. LDPE is weaker, softer and more permeable than high density polyethylene (HDPE). It is also easier to bend, mold and weld into flexible plastics parts that have high impact resistance. LDPE is typically translucent or opaque.

Synonyms and Related Terms

LDPE; low-density polyethylene; polietileno de baja densidad (Esp.); polyéthylène basse densité (Fr.); polietilene ad bassa densità (It.); polietileno de baixa densidade (Port.)

Applications

  • Plastic bags; recyclable (symbol #4) at some in-store collection locations
  • Parts that need to be welded or molded
  • Trays and general purpose containers

Risks

  • Breaks down in UV light forming methane and ethylene
  • Dust may cause irritation.
  • Susceptible to stress cracking
  • Genesis Polymers: SDS

Physical and Chemical Properties

  • For a 1 mil film: Oxygen transmission = 1368-4256 ml/m2d
  • Water vapor transmission = 57-76 g/m2d
  • Density range of 917-930 kg/m3
  • Resistant to most solvents except nitric and hydrochloric acids. May swell in oil.
  • Can withstand continuous temperatures of 65C

Comparisons

General Characteristics of Polymers

Physical Properties for Selected Thermoplastic Resins

Resources and Citations

  • Wikipedia: Low density polyethylene
  • Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
  • Pam Hatchfield, Pollutants in the Museum Environment, Archetype Press, London, 2002
  • Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
  • Theodore J. Reinhart, 'Glossary of Terms', Engineered Plastics, ASM International, 1988