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D1468-93 – Standard Test Method Technical Guide
ASTM D1468 – 93 (Reapproved 2001) provides a standardized procedure for determining the volatile matter in tricresyl phosphate. This measurement is essential for specification acceptance and assessing performance in plasticizer applications. The method relies on precise heating and weighing steps.
📐 Test Method Overview
This test method is under the jurisdiction of ASTM Committee D-1 on Paint and Related Coatings, Materials, and Applications. The primary purpose is to quantify volatile components in tricresyl phosphate, which can affect its suitability as a plasticizer. The standard emphasizes safety due to the hazardous nature of tricresyl phosphate, including potential inhalation and skin absorption risks, and the toxicity of its ortho-isomer.
⚙️ Apparatus and Procedure
The apparatus required includes a thermostatically controlled oven and a flat dish. Specifications are as follows:
| 🛠️ Equipment | 🔬 Specification |
|---|---|
| Oven | Thermostatically controlled at 105 ± 5°C |
| Petri Dish | 100-mm diameter, or equivalent (flat aluminum, glass, or porcelain) |
The procedure involves:
- Place the dish in the oven at 105 ± 5°C for 1 hour.
- Cool in a desiccator and weigh to 10 mg.
- Spread approximately 25 g of the sample evenly over the dish.
- Weigh dish and specimen to 10 mg.
- Heat in oven at 105 ± 5°C for 3 hours.
- Cool in desiccator and reweigh to 10 mg.
📊 Calculation and Precision
Calculate volatile matter using the formula:
Volatile matter, % = ((S − R) / S) × 100
where S is the initial specimen weight and R is the weight after heating.
Precision data from the standard:
| 🟦 Criteria | 📐 Within Laboratory | ⚡ Between Laboratories |
|---|---|---|
| Volatile matter, weight % | 0.05 | 0.1 |
⚠️ Hazard Note: Tricresyl phosphate is hazardous through inhalation or skin absorption. The ortho-isomer is toxic. Use appropriate safety gear and work in a fume hood. Refer to Material Safety Data Sheet for guidance.
💡 Best Practice: For accurate results, allow the oven to reach steady state at 105 ± 5°C before starting. Use a desiccator with fresh desiccant to ensure complete cooling without moisture gain.
❓ Frequently Asked Questions
🔍 What is the scope of ASTM D1468?
It covers the determination of volatile matter in tricresyl phosphate for specification acceptance and plasticizer performance evaluation.
💡 What temperature and duration are used for heating?
The specimen is heated at 105 ± 5°C for exactly 3 hours to ensure consistent volatile loss.
⚡ How is volatile matter percentage calculated?
It is calculated as the weight loss divided by the initial weight, multiplied by 100: % = ((S − R) / S) × 100.
📌 What are the precision limits for this test?
Results should not differ by more than 0.05 weight% within a laboratory and 0.1 weight% between laboratories.