Butylated Hydroxy Toluene in Polymers of Ethylene and Ethylene–Vinyl Acetate ASTM D4275
The ASTM D4275 test method consists of solvent extraction proceeded by a gas chromatographic analysis approach for determining butylated hydroxytoluene (BHT) (2,6- di-t-butyl-4 methyl-hydroxybenzene) in ethylene and ethylene-vinyl acetate (EVA) copolymers.
ASTM D4275 test technique utilizes gas chromatography for the detection of butylated hydroxytoluene (BHT) in ethylene polymers and ethylene-vinyl acetate (EVA) copolymers. Stabilizers used in the production of polypropylene are separated and evaluated in order to link performance characteristics to the polymer composition. Flame ionization is used to detect the substance, and internal or external standards are used to obtain the quantitative analysis.
For ASTM D4275, BHT is extracted from a finely ground polymer sample by shaking or refluxing it with cyclohexane or isopropanol. A known volume of the extract is injected into a liquid-coated solid support gas chromatographic column. BHT is separated from the extraction solvent and other components in a stream of carrier gas passing through this column. A flame ionization detector measures the responses of BHT and any other internal standard. The relative concentration and retention time of BHT are indicated by its signal.
For ASTM D4275 test method, finely ground polymers of ethylene and ethylene-vinyl acetate copolymers are used as a test specimen.
The concentration of BHT in the polymer is reported in ppm.
The BHT content of each is calculated from the following equation:
BHT (in ppm by weight) = BV / SW
B = BHT area or peak height from sample chromatogram