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November - December 2016
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modified with additives to have
any hope of lasting. They also
have very poor (high) pour
points, so their use in cold envi-
ronments is very limited
without using additives.
Synthetic esters are made
from organic acids and alco-
hols. Originally formulated as a
replacement for triglycerides,
they perform better in nearly
every performance criteria.
They work better at both higher
and lower temperatures, have
low volatility and a higher
lubricity all while maintaining
decent biodegradability.
Polyglycols offer many of the
same benefits as synthetic esters
but do not react with water as
readily as the esters. They have
excellent lubricity and high
viscosity indexes, and perform
well at both high and low
temperatures. One specific
property of polyglycols that is
beneficial in terms of the envi-
ronment is that they are nearly
nontoxic in aquatic environ-
ments like rivers and lakes. Their
one downfall is that they are not
compatible with hydrocar-
bon-based fluids.
If you have a question for one of
Noria's experts, email it to editor@
noria.com.
