Stress relaxation studies on wool fibers

✍ Scribed by V. B. Gupta; D. Rama Rao

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 685 KB
• Volume: 45
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1992.070450206

✦ Synopsis

Starting with the work reported by Speakman in 1928,' a number of authors have made important contributions to the understanding of the stress relaxation of wool fibex2-l6 This relaxation is attributed to the breaking of various physical and chemical crosslinks on extension and their reformation with the passage of time. Based on the time scale over which they are effective, these bonds are categorized into three main groups:'

1. Weak bonds having relaxation times below

0.1 min including hydrogen bonds, salt linkages, and van der Waals and electrostatic forces.

2. Bonds of intermediate strength having relax-

ation times between 0.1 and 10 min, due to disengagement of bonds between matrix and filament components.

3. Strong bonds having relaxation times above

10 min, consisting of covalent crosslinkages, mainly disulfide bonds.

These three categories of relaxation mechanisms are referred to as low, intermediate, and long time relaxation processes. The intensity and rate of relaxation depends on test conditions such as temperature, humidity, and strain history.

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