10. Isophthalic Acid Content
10.1 A rapid and simple procedure for the gravimetric
determination of isophthalic acid in alkyd resins is provided in
Test Method D 2690. There is no interference in this test
method from styrene monomer of polymer or from other
dicarboxylic acids except terephthalic acid, which is recovered
quantitatively.
11. Polyhydric Alcohol Content
11.1 The polyhydric alcohols in alkyds can be determined
qualitatively and quantitatively in accordance with the procedure in Test Method D 2998. The resin to be analyzed is dried,
subjected to aminolysis, and treated to form trimethylsilyl ether
derivatives of the alcohols which are separated by gas-liquid
chromatography. An internal standard is used for quantitative
purposes. Flame-ionization detectors cannot be used with Test
Method D 2998.
12. Identification of Carboxylic Acids
12.1 Method D 2455 describes a procedure for the qualitative determination of all the carboxylic acids in alkyd resins,
including resin-modified alkyds. This procedure makes use of
gas chromatographic separation of the methyl esters of the
respective acids that are formed by direct transesterification of
the resin with lithium methoxide. The acids, including the fatty
acids, are identified by their relative retention time which is
given for 23 acids and others may be added if desired. Since
maleic and fumaric acids react differently than the other acids
encountered, an alternative procedure is supplied for their
differentiation. It is sometimes possible to identify the drying
oils in the alkyd from the fatty acid esters that appear in this
procedure, but it is not as reliable for oil identification as
Method D 2245 (Section 8).
10. Isophthalic Acid Content
10.1 A rapid and simple procedure for the gravimetric
determination of isophthalic acid in alkyd resins is provided in
Test Method D 2690. There is no interference in this test
method from styrene monomer of polymer or from other
dicarboxylic acids except terephthalic acid, which is recovered
quantitatively.
11. Polyhydric Alcohol Content
11.1 The polyhydric alcohols in alkyds can be determined
qualitatively and quantitatively in accordance with the procedure in Test Method D 2998. The resin to be analyzed is dried,
subjected to aminolysis, and treated to form trimethylsilyl ether
derivatives of the alcohols which are separated by gas-liquid
chromatography. An internal standard is used for quantitative
purposes. Flame-ionization detectors cannot be used with Test
Method D 2998.
12. Identification of Carboxylic Acids
12.1 Method D 2455 describes a procedure for the qualitative determination of all the carboxylic acids in alkyd resins,
including resin-modified alkyds. This procedure makes use of
gas chromatographic separation of the methyl esters of the
respective acids that are formed by direct transesterification of
the resin with lithium methoxide. The acids, including the fatty
acids, are identified by their relative retention time which is
given for 23 acids and others may be added if desired. Since
maleic and fumaric acids react differently than the other acids
encountered, an alternative procedure is supplied for their
differentiation. It is sometimes possible to identify the drying
oils in the alkyd from the fatty acid esters that appear in this
procedure, but it is not as reliable for oil identification as
Method D 2245 (Section 8).
การแปล กรุณารอสักครู่..
