LDPE Film Properties

Overview

What is LDPE?

Low-density polyethylene (LDPE) is a heat sensitive polymer that is sourced

from petroleum. It is also the first polyolefin to be developed.

It is manufactured by polymerization of a simple hydrocarbon known as

ethylene (h2c=ch2), under high-pressure conditions. LDPE finds extensive

usage due to its low density in the manufacture of wash bottles, tubing,

dispensing bottles, plastic food containers etc.

What is LDPE film?

The LDPE when shaped in such a fashion that its length and breadth are

significantly greater than its thickness, is called a LDPE film.

General Properties:

Low-density polyethylene (LDPE) is known for it’s heat sensitivity and has a

maximum temperature of 176°f while the minimum temperature is -58°f. Melting

point of LDPE is measured to be 248°f or 120°c. LDPE’s tensile strength is

measured at 1700 psi while the specific gravity is 0.92. Crystallanity of LDPE is

pegged in the range of 50-60%.

Basic Chemical Properties of LDPE:

Poor ultraviolet resistance characterizes LDPE, however, all forms are chemically

resistant to non-hydrocarbon chemicals. LDPE is un-reactive at room

temperatures. It is more flexible when compared to HDPE due to its lower

crystallinity. LDPE is known to be transparent because it is more amorphous than

HDPE.

Physical Properties of LDPE:

LDPE is translucent due to its low density and reduced crystallinity. It is

highly flexible and has a good tensile strength.

Since it is a thermoplastic, LDPE is easily heat welded.

LDPE cannot be made to adhere to with glues.

It is easily machined and welded.

Its flexibility is retained over a wide range of temperatures.

Resistance Properties:

LDPE films are generally resistant to most of the chemical attacks. These are

detailed below:

Highly resistant against dilute and concentrated esters, acids, bases and

alcohols.

Partially resistant against aldehydes and ketones.

Little resistance against aromatic hydrocarbons, mineral oils, aliphatic

hydrocarbons.

Poor resistance against halogenated hydrocarbons and oxidizing agents.

Environmental and Recycling Properties:

LDPE (low-density polyethylene) is employed in the manufacture packaging

products, which cannot be easily recycled. E.g. diapers, plastic wrap, and squeeze

bottles. LDPE is generally not easy to recycle and is recognized by the recycling

symbol 4. The energy requirement for production of LDPE varies between 73-107

MJ/kg, with an average of 88.55 MJ/kg.

Electrical Properties:

Low-density polyethylene (LDPE) has excellent dielectrical properties. It’s

resistivity has been established at 5e+17 - 1e+21 Ohm.mm2/m with a breakdown

potential of 17.7 - 39.4 kV/mm and a low dielectric loss factor between

0.0002 - 0.001. Due to these properties LDPE is widely used in wiring and cabling

applications.

References:

1. http://bama.ua.edu/~joshua/archive/may09/Nettles.pdf

2. http://adsabs.harvard.edu/abs/1998NIMPB.141..202B

3. http://www.drc.ohiolink.edu/handle/2374.OX/5888?show=full

4. http://www.sks-bottle.com/LDPEHelp.html

5. http://www.matbase.com/material/polymers/commodity/ldpe/properties

6. http://www.procurefast.com/index.php?

option=com_virtuemart&Itemid=116