Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D2764-20 – Standard Test Method Technical Guide
📐 Scope and Significance
This standard (D2764-20) defines an empirical test method for measuring the dimethylformamide-insoluble (DMF-I) content in tar and pitch. The test is crucial for evaluating and characterizing these materials, providing a rapid and reasonably accurate way to establish the uniformity of shipments or sources of supply. It serves as a strong correlative measure to the toluene-insoluble (TI) content determined via Test Method D4072. Strict adherence to every detail of the procedure is necessary, as the method is empirical and outcomes are procedure-dependent.
⚙️ Test Apparatus and Materials
The following specific equipment and reagents are mandated by D2764-20 to ensure consistent test results:
| 🟦 Apparatus | 📏 Specification Per Standard |
|---|---|
| Filtering Crucible | Porcelain, high form, fine-porosity bottom; 30–40 mL capacity; max pore diameter 7 µm |
| Water Bath | Maintained at 203 °F to 212 °F (95 °C to 100 °C) |
| Test Sieves | U.S. Standard 600 µm (No. 30) and 250 µm (No. 60), conforming to Specification E11 |
| Filter Apparatus | Filter flask and tube with a crucible adapter |
| 🧪 Reagent / Material | 🎯 Specification & Handling |
|---|---|
| Dimethylformamide (DMF) | Reagent grade. Boiling range 4 °F (2 °C) including 307 °F (153 °C). Stored over desiccant, filtered to optical clarity before use. |
| Celite Analytical Filter Aid (CAFA) | Dried to constant mass at 221 °F (105 °C). Stored in a tightly stoppered container. No other filtering medium is permitted. |
| Acetone | Meeting Specification D329. (Warning—Flammable. Health hazard.) |
📊 Summary of Test Method
A sample of tar or pitch is digested in hot dimethylformamide (DMF). The insoluble matter is then filtered using a prepared porcelain crucible containing a bed of Celite Analytical Filter Aid. The residue is washed, dried to a constant mass, and weighed. The procedure precisely controls particle size through the required 600 µm and 250 µm sieves, digestion temperature via a water bath held at 203–212 °F (95–100 °C), and filtration through a crucible with a maximum pore diameter of 7 µm.
⚠️ Crucial Adherence Required: The standard is empirical (Section 1.2), meaning precise execution of every step is mandatory for valid results. Always consult the specific safety data sheets and regulatory limitations for the hazardous solvents used (Sections 1.4, 6.2, 7.1).
💡 Filter Medium