Cork insulation; a complete illustrated textbook on cork insulation ...

238 CORK INSULATION
at 105° C. The residue consists of the fatty and resin acids present
in the emulsion.
Water.—The percentage of water in the emulsion is determined
by distilling a 100-gram sample in the retort used for dehydration.
The distillation is carried out in exactly the same manner as described
under this test until the volume of water in the receiver shows
no further increase. Any oils that come over are thoroughly mixed
with the material remaining in the retort.
Aiiniionia.—Many emulsions contain ammonia, and when this is
present a second distillation of the material is necessary. This is
carried out on a 100-gram sample in exactly the same manner as
described for the determination of water, except for the fact that 40
cubic centimeters of a 10 per cent, solution of caustic potash is added
to the contents of the retort before beginning the distillation. The
distillate is collected in a measured volume of N/2 sulphuric acid.
When the distillation is <strong>complete</strong>d the excess acid is titrated with
N/2 caustic potash, and the ammonia thus determined.
Ash.—A one-gram sample of the dehydrated material is ignited in
a weighed platinum or porcelain crucible. The ash will contain any
inorganic matter from the bitumen as well as the fixed alkali present
in the soap. The results are, of course, all calculated on the basis
of the original material.
Total Bitumen.—A two-gram sample of dehydrated material is
extracted with carbon disulphide as described in the method for the
determination of total bitumen, flask method, and in this manner
the organic matter insoluble in carbon disulphide can be determined.
Having determined all constituents as above noted, it is assumed
that the difiference between their sum and 100 per cent, is bitumen,
which amount is reported accordingly.
It will be seen that with emulsified asphalt, as with many
"prepared" products, the average purchaser must rely on the
manufacturer for the quality and fitness of the emulsion for the
work in hand.
The advantage offered by a suitable emulsified asi)halt as
a priming material for masonry surfaces, as compared with
an Asphalt primer, is that emulsified asphalt is non-inflammable
; and the advantage of the Asphalt primer over the
emulsion is that the asphalt that is cut with a solvent can be
handled with an air-gun at much higher pressures, and thus
with greater penetration, than the emulsion can be handled.
If too great pressure is used with the emulsion, the air-gun is
liable to foul in the nozzle and clog; because the excessive
pressure tends to force too much water out of the emulsion
and coagulate the asphalt in the nozzle.