SPI-Pon 812 can also be the preferred "Epon substitute" resin for samples
that have solubilities for the resin monomers (that is, the samples could be
dissolved by the monomer or combination of monomers).
Special methods have been published for applications with these kinds of
samples. Interesting enough, the resin has great versatility, one can
find it just as likely to be the resin of choice for embedding biological
tissue material as they are, the resin of choice for embedding solid
catalyst or other plastic samples. No other resin is known to us that can
be used over such a broad range of samples representing such a wide range of
hardness.
Note that the DMP-30 in the formulation has a relatively short shelf
life, but, there are precautions one can take to
lengthen it, thereby mitigating in some respects that one particular and
known disadvantage. Also, the user should appreciate that this resin does
not work well in the presence of even a slight amount of moisture. So
in addition to the obvious (resin does not cure right), any moisture
present results in gas bubbles being formed during the polymerization
which results in a really terrible embedment.
Note about bubbles in the final cured block: One of the more common
"problems" is the appearance of bubbles in the final cured block. This is
usually the result of retained moisture in the sample. Depending on the
sample itself, there are obviously different ways one could use to remove
residual moisture. But bubbles are usually the result of moisture in the
same.
Hardness vs. viscosity: Another one of the trade offs faced regularly by
microscopists is that of resin viscosity vs. hardness of the final block. By
way of the addition of excess hardener, one can make a block out of SPI-Pon 812
that is as hard as any resin and certainly harder than a lot of resins.
Polymerizing under such conditions does result in a higher viscosity of the
resin and therefore potentially less effective infiltration. But we always
recommend this as the place to start since the alternatives are both more
expensive and more complicated to use. For a lower viscosity embedment, we
recommend trying SPI-Chem Low Acid GMA, TEM formulation.
The GMA monomer has a viscosity slightly less than that of water.
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