Definition
UHMWPE is
the acronym of Ultra High Molecular Weight PolyEthylene
UHMWPE is
a linear, low-pressure, Ziegler-type-catalyst, polyethylene resin.
Comments
UHMWPE has an extremely weight-average
molecular weight, approximately ten times that of high molecular weight, High
density polyethylene (HDPE) resins.
Because of
its ultra high molecular density, UHMWPE has both the highest abrasion
resistance and highest impact strength of any plastic.
In fact, a
25mm (1″) thick slap can stop a 0.38 caliber pistol
slug at 150 mm (6″).
UHMWPE is
the simple linear background (PE) polymers with unique properties.
UHMWPE has
highest impact strength among the other engineering polymers along with
excellent abrasion and wear resistance, biocompatibility, noise resistance,
very low coeficient of friction, good chemical resistance and electrical
insulation resistance.
Combined
with abrasion resistance and toughness, the low coefficient of friction of
UHMWPE yields a self-lubricating, non-stick surface.
Static and
dynamic coefficients are significantly lower than steel and most plastic
materials.
UHMWPE can
act as a biomaterial, especially as in total joint replacement components as
for example hip prosthesis or any joint replacement surgery.
Components
made from UHMWPE are subject to complex loading over extended periods of time.
UHMWPE has
high viscosity even above the melting temperature.
Thus, it
is difficult to process pure UHMWPE by injection molding, blow
molding, or conventional screw extrusion.
However,
reducing the viscosity by the addition of short chain oligomers could affect
the properties of the products.
The poor
processability restricts the extensive existing applications of UHMWPE.
To
facilitate its processing for applications, UHMWPE is combined with
polyethylene (PE), polypropylene (PP), polyacrylate (PA), polycarbonate (PC),
polyaniline (PANI), and other materials to improve the properties of such
polymers.
High
density polyethylene (HDPE) has been widely used in the industry on account of
good processability, desired properties and relatively low cost.
The
UHMWPE/HDPE blend has drawn much attention as a promising human joint repair
material because such a blend has better creep resistance than neat UHMWPE
Furthermore,
HDPE is also a biocompatible polymer and the presence of HDPE could improve the
processibility of a UHMWPE blend.
Many
properties of UHMWPE/HDPE blend have been studied, such as processing
performance, rheological properties, thermal oxidative properties and impact
behavior.
If UHMWPE
is not so much known outside a circle of specialists, its applications are
well-known in the industry, biomedical and protection sectors.
