MIL-DTL-12276E(MR)
that does not exceed 0.3 gram in weight. Dissolve in 2 ml. of reagent grade toluene and dry
the dish for 30 minutes in a gravity convection oven at 105o ± 2o C. Determinations shall be
run in duplicate. Upon cooling, reweigh to the nearest 0.1 milligrams and calculate the
percent total solids:
Weight of Residue X 100
Percent Solids =
Weight of Sample
4.3.6 Solvent analysis for composition L.
4.3.6.1 Separation of volatile portion. Pour about 15 grams of the varnish into a 50 ml.
distilling flask. Add 10 ml. of tricresyl phosphate and several anti-bumping stones or Berl
Saddles. Fit a release valve into the mouth of the flask and attach a delivery tube to the side
arm, extending into a receiver. The receiver consists of a test tube (20 x 150mm) with side
arm for attaching to a vacuum pump. The glass delivery tube should reach 1 ½ inches from
the bottom of the tube. Immerse the receiver in a dry ice-acetone bath. Preheat a silicone oil
bath to 160o C. Raise the oil bath until the oil reaches the sample level. Reduce the pressure
slowly to 10mm of mercury. After all the solvent has distilled, carefully release the vacuum
using the valve that is connected to the distilling flask. Reserve the collected distillate for
the aromatic solvent determination and the test for ketone, olefinic and cyclo-olefinic
compounds.
4.3.6.2 Determination of aromatic hydrocarbons.
4.3.6.2.1 Qualitative test for aromatic hydrocarbons. Place 5 ml. of the distillate in a 10 ml.
glass stopped graduate. Add 5 ml. of 86 percent sulfuric acid slowly while the graduate is
being cooled with tap water. After the acid has been added, shake vigorously for 2 minutes,
then allow the layers to separate. If there is no separation of layers, it can be assumed that
no aromatic hydrocarbons are present. If there is an upper layer, determine the aromatic
hydrocarbons quantitatively as described in 4.3.6.2.2.
4.3.6.2.2 Qualitative determination of aromatic hydrocarbons.
APPARATUS: A gas chromatograph equipped with a thermal conductivity detector.
COLUMN PREPARATION: Two lengths of ¼ inch copper tubing, 6-ft. and 18-ft.
long. Packed with 35 percent N, N-Bis (2-cyanoethyl)
formanide on 60- to 80-mesh Chromosorb P.
OPERATING CONDITIONS:
6-FT.
18-FT.
o
Detector cell temperature, C
300
300
Detector cell current, mA
150
150
Injection port temperature, oC
300
300
Helium flow at exit, cc/minute
175
110
Column temperature, oC
125
70
7
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