Application Note B-TA1072
Introduction
There are natural fibers derived from plants or animals, and chemical fibers that are chemically synthesized. Moisture absorption and water absorption are among the physical properties of fibers, and they are particularly important when fibers are used in clothing, bedding, and similar applications.
In this study, the mass changes of natural textiles (cotton and linen) and chemical fibers (acrylic and polyester) were compared under varying controlled relative humidity conditions.
Measurement and analysis example
As samples, sheets of cotton, linen, acrylic, and polyester were punched into 4 mm diameter pieces, and approximately 3.5 mg of each was placed in an aluminum pan. The temperature was maintained at 25°C, and the relative humidity was gradually changed from dry to 80%RH in 20%RH increments, with each step held for 35 minutes before measurement.
Figure 1: Comparison of measurement results of TG
The table below shows the mass change percentage at each controlled relative humidity.
| Mass change percentage (%) at each controlled relative humidity | ||||||||
| 20%RH | 40%RH | 60%RH | 80%RH | 60%RH | 40%RH | 20%RH | dry | |
| Cotton | 2.5 | 4.1 | 5.8 | 8.1 | 6.7 | 4.9 | 3.1 | 0.8 |
| Linen | 2.1 | 3.7 | 5.4 | 8.1 | 6.5 | 4.5 | 2.7 | 0.4 |
| Acrylic | 0.6 | 0.8 | 1.0 | 1.1 | 0.9 | 0.6 | 0.3 | 0.0 |
| Polyester | 0.4 | 0.4 | 0.5 | 0.7 | 0.4 | 0.2 | 0.1 | 0.0 |
All fiber types showed an increase in mass due to moisture absorption as relative humidity increased, followed by mass loss as relative humidity decreased.
Comparison of the mass changes revealed that natural fibers (cotton and linen) exhibit higher moisture absorption properties than chemical fibers (acrylic and polyester). Furthermore, between acrylic and polyester, acrylic showed a slightly larger mass increase, indicating that acrylic has higher moisture absorption property.
