SleepTech July - August 2018

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isocyanate and toluene-2,6-diisocyanate
with the 2,4- isomer
being the major component.
Polyurethane chemistry was first
studied and produced in Germany
in 1937. Polyurethanes represent
a family of polymers rather than a
single polymer. Urethane polymers
can be produced with a wide
variety of properties, ranging
from soft flexible foams and fibers
through to hard solids so that
they can be used in a diverse
range of applications. The TDI is
consumed in the chemical reaction
that makes polyurethane and is
not released from the finished
polyurethane foam into the air.
Flexible polyurethane foam is used
in mattresses, furniture cushions
and other common household
applications.
The development of elastic polyurethanes
began as a program
to find a replacement for rubber
during the days of World War II.
In 1940, the first polyurethane
elastomers were produced. These
compounds gave millable gums
that could be used as an adequate
alternative to rubber. When
scientists found that polyurethanes
could be made into fine
threads, they were combined
with nylon to make more lightweight
and stretchable garments.
Polyurethanes are linear polymers
that have a molecular backbone
containing carbamate groups
(-NHCO2). These groups, called
urethane, are produced through
a chemical reaction between a
diisocyanate and a polyol. Polyurethanes
are some of the most
versatile polymers. Despite these
differing properties, the polymers
have one common characteristic in
that they all incorporate the urethane
group (-NH-CO-O-) into their
structure. However, the polymers
differ from simple thermoplastic
polymers, such as the polyolefins,
in that they are not sold as readymade
polymers but as precursors
that are mixed at the conversion
stage. These precursors are commonly
polyols (compounds containing
multiple -OH groups) and
diisocyanates (compounds containing
-NCO groups). The primary
reaction during the production of
polyurethanes is of the form: -NCO
+ HO- → -NH-CO-O-
Polyurethane flexible foams can
be used for a diverse range of
applications including sofa, mat-