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- Nitrile
gloves are made from a synthetic polymer that exhibits rubber
like characteristics when vulcanized. The polymer is made in the form
of a latex or emulsion and can be used or processed very much like natural
rubber latex. There are some differences which make this polymer unique.
Unlike natural rubber which is polyisoprene, the backbone of the nitrile
polymer is composed of three ingredients or monomers ("mono" meaning
one and "mer" meaning unit), namely acrylonitrile, butadiene and a carboxylic
acid. The term "terpolymer" is sometimes used to describe a combination
of the three different monomers. The word "polymer" implies by contrast,
"many units " put together in unique ways to form a large molecule.
- The
other significant difference between natural rubber and nitrile
latex is that natural rubber contains proteins which act as stabilizers.
These proteins can cause allergic reactions since they remain in the
finished glove. Nitrile lattices on the other hand do not contain any
proteins but instead are stabilized by anionic surfactants. The nitrile
latex can be coagulated to form a film by using calcium nitrate, just
as in the case of natural latex, but without the added complication
of proteins.
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In addition,
nitrile gloves can dissipate electrostatic charge much better than natural
rubber and this can be a valuable feature in the semiconductor industry.
Because of their good abrasion resistance, they also generate significantly
less particulate matter that can potentially act as contaminants during
manufacturing.
- The
other difference between natural rubber and nitrile latex
is that natural rubber is a linear polymer and hence has to undergo
a precuring step to enhance its strength before dipping. Nitrile polymers
on the other hand are inherently crosslinked during manufacture so that
little or no precuring is necessary to enhance its strength. This can
be a process advantage. The degree of this crosslinking can be altered
by changing the process conditions or by adding agents known as chain
modifiers during manufacture.
- So
no matter what the ultimate end use, nitrile polymers can
be significantly tailored to achieve those needs in a variety of ways.
In the case of natural rubber, one is essentially limited by nature's
creation, with no room for change.
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