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D2402-07 – Standard Test Method Technical Guide
The ASTM D2402-07 (Reapproved 2018) standard outlines a centrifuge procedure to measure the water retention of textile fibers. This method quantifies the water remaining in thoroughly wetted fibers after mechanical removal via centrifugal force.
📐 Specimen Geometry and Types
This test method is applicable to man-made and natural fibers in forms such as staple, tow, filament, and spun yarns. Sampling must adhere to standards like D3333 for manufactured staple fibers and D2258/D2258M for yarns. The specimen must be completely wetted-out before testing.
| 🟦 Fiber Type | 📏 Form | 📐 Sampling Standard |
|---|---|---|
| Man-made | Staple, Tow, Filament | D3333 |
| Natural | Staple, Filament, Yarn | D2258/D2258M |
⚙️ Test Procedure and Speed Selection
The specimen is immersed for thorough wetting, then centrifuged at an acceleration of 9800 m/s² for exactly 5 minutes. This force removes mechanically removable water. After centrifuging, the wet specimen is weighed, dried in an oven, and reweighed to obtain dry mass.
| 📊 Parameter | ⚡ Specification |
|---|---|
| Centrifuge Acceleration | 9800 m/s² |
| Duration | 5 minutes |
| Wetting Condition | Thorough immersion |
Note: The centrifuge must provide an acceleration of 9800 m/s². Regular calibration is required to maintain accuracy, as deviations can significantly impact results.
📊 Key Measured Properties
Water retention (WR) is calculated as a percentage of the dry mass: WR = (Wet mass – Dry mass) / Dry mass × 100%. This value reflects the hydrophilic nature of the fiber. It can indicate differences between fiber types, degree of cross-linking in cellulosic fibers, or damage. However, this test is more appropriate for development and research than for acceptance testing of commercial shipments.
Tip: For acceptance testing, comparative studies using Student’s t-test are advised to resolve disputes between laboratories, as per Section 5.1.1.
❓ Frequently Asked Questions
🔍 What is the scope of ASTM D2402-07?
This test method covers water retention measurement for man-made and natural fibers as staple, tow, filament, and spun yarns, using a centrifuge procedure.
This test method covers water retention measurement for man-made and natural fibers as staple, tow, filament, and spun yarns, using a centrifuge procedure.
💡 How is water retention calculated?
Water retention is calculated as the percentage of water mass relative to dry mass: (Wet mass after centrifuging – Dry mass) / Dry mass × 100%.
Water retention is calculated as the percentage of water mass relative to dry mass: (Wet mass after centrifuging – Dry mass) / Dry mass × 100%.
⚡ What are the critical centrifuge parameters?
The specimen is centrifuged at an acceleration of 9800 m/s² for 5 minutes.
The specimen is centrifuged at an acceleration of 9800 m/s² for 5 minutes.
📌 Is this method recommended for acceptance testing?
It is primarily for research and development. If used for acceptance, comparative tests with statistical analysis are necessary to identify biases.
It is primarily for research and development. If used for acceptance, comparative tests with statistical analysis are necessary to identify biases.