polyethylene or polythene
DESCRIPTION
Polyethylene or Polythene. Density – 0.9 g / mm. Muralimanohar.D. Polyethylene. Polyethylene or polythene is a thermoplastic commodity heavily used in consumer products . Over 60 million tons of the material are produced worldwide every year - PowerPoint PPT PresentationTRANSCRIPT
Polyethylene or Polythene
8/9/2008 1PE - An Over View
Muralimanohar.D
Density – 0.9 g / mm
Polyethylene
8/9/2008 2PE - An Over View
Polyethylene or polythene is a thermoplastic commodity heavily
used in consumer products . Over 60 million tons of the material
are produced worldwide every year
In the polymer industry the name is sometimes shortened to PE
Classification of Polyethylene
8/9/2008 3PE - An Over View
Polyethylene is classified into several different categories
based mostly on its density and branching. The mechanical
properties of PE depend significantly on variables such as the
extent and type of branching, the crystal structure and the
Molecular weight.
Polyethylene Classification Cont’d
8/9/2008 4PE - An Over View
Ultra high molecular weight polyethylene(UHMWPE)
Ultra low molecular weight polyethylene(ULMWPE - PE-WAX)
High molecular weight polyethylene(HMWPE)
High density polyethylene(HDPE)
High density cross-linked polyethylene (HDXLPE)
Cross-linked polyethylene(PEX)
Medium density polyethylene(MDPE)
Low density polyethylene(LDPE)
Linear low density polyethylene(LLDPE)
Very low density polyethylene(VLDPE)
Polyethylene Classification Cont’d
8/9/2008 5PE - An Over View
Physical properties
Depending on the crystallinity and molecular weight, a melting point and
glass transition may or may not be observable. The temperature at which
these occur varies strongly with the type of polyethylene. For common
commercial grades of medium- and high-density polyethylene the melting
point is typically in the range 120 to 130 °C ((250 to 265 °F). The melting
point for average, commercial, low-density polyethylene is typically 105 to
115 °C (220 to 240 °F).
Polyethylene Classification Cont’d
8/9/2008 6PE - An Over View
Physical properties cont’d
Most LDPE, MDPE and HDPE grades have excellent chemical resistance and
do not dissolve at room temperature because of their crystallinity.
Polyethylene (other than cross-linked polyethylene) usually can be
dissolved at elevated temperatures in aromatic hydrocarbons such as
toluene or xylene, or in chlorinated solvents such as trichloroethane or
Trichlorobenzene.
Ultra high molecular weight polyethylene
8/9/2008 7PE - An Over View
Ultra high molecular weight polyethylene (UHMWPE), also known as high-
modulus polyethylene (HMPE) or high-performance polyethylene (HPPE),
is a subset of the thermoplastic polyethylene. It has extremely long chains,
with molecular weight numbering in the millions, usually between 2 and 6
million. The longer chain serves to transfer load more effectively to the
polymer backbone by strengthening intermolecular interactions.
n greater than 100,000
Ultra high molecular weight polyethylene Cont’d
8/9/2008 8PE - An Over View
This results in a very tough material, with the highest impact strength of any
thermoplastic presently made. It is highly resistant to corrosive chemicals,
with exception of oxidizing acids. It has extremely low moisture absorption,
has a very low coefficient of friction, is self-lubricating, and is highly
resistant to abrasion (15 times more resistant to abrasion than carbon steel).
Its coefficient of friction is significantly lower than that of nylon and acetal,
and is comparable to that of Teflon, but UHMWPE has better abrasion
resistance than Teflon. It is odorless, tasteless, and nontoxic.
Ultra high molecular weight polyethylene Cont’d
8/9/2008 9PE - An Over View
Trade names
Dyneema is a registered trademark of Royal DSM N.V. (The Netherlands).
Honeywell developed a product identical in chemical structure, which is
sold under the brand name Spectra
Other trade names for consolidated UHMWPE materials include TIVAR by
Quadrant EPP Inc., Polystone-M by Röchling Engineering Plastics, Tensylon
by Integrated Textile Systems, and GARDUR by Garland Manufacturing
Ultra high molecular weight polyethylene Cont’d
8/9/2008 10PE - An Over View
Usage
Fiber applications
Ballistic vests, ballistic helmets and ballistic vehicle protection, bow strings, climbing equipment, fishing line, spear lines for spearguns, high-performance sails, suspension lines on sport parachutes, rigging in yachting
Medical Applications in Total Joint Replacement
UHMWPE has over 40 years of clinical history as a successful biomaterial for use in hip, knee, and for spine implants
Skis and snowboards
The bottom of most modern skis — the surface that contacts the snow — is coated with UHMWPE, treated for compatibility with waxes and with epoxy base material
Ultra high molecular weight polyethylene Cont’d
8/9/2008 11PE - An Over View
Hockey
Ice hockey and field hockey sticks use Dyneema as a material to reinforce the body of the stick.
High-density polyethylene (HDPE) forth coming week……………
8/9/2008 12PE - An Over View
Thank you