How does liquid ammonia treatment improve the wrinkle resistance and dimensional stability of liquid nitrogen sweat fabrics?

1. Basic principles of liquid ammonia treatment

Liquid ammonia treatment is a process that uses liquid ammonia to modify fibers. Under low temperature and high pressure, liquid ammonia can penetrate into the fiber and interact with the fiber molecules. This effect is mainly reflected in two aspects: first, liquid ammonia molecules can destroy the hydrogen bonds inside the fiber and rearrange the fiber molecular chains; second, liquid ammonia treatment can change the crystal structure of the fiber and enhance its stability. These changes directly affect the wrinkle resistance and dimensional stability of the fabric.

2. How does liquid ammonia treatment improve the wrinkle resistance of the fabric?

1. Release stress inside the fiber
During the production and weaving process of the fiber, due to processes such as mechanical stretching and heat setting, certain stresses will accumulate inside the fiber. These stresses are the main reason for the wrinkles of the fabric during wearing and washing. Liquid ammonia treatment penetrates into the fiber, destroys the hydrogen bonds between the fiber molecules, and rearranges the molecular chains, thereby releasing internal stress. This stress release makes the fabric less likely to produce permanent wrinkles when subjected to external forces, improving its wrinkle resistance.

2. Improve the elastic recovery ability of fibers
Liquid ammonia treatment can not only release the stress inside the fiber, but also enhance the elastic recovery ability of the fiber. The molecular chains of the fibers treated with liquid ammonia are arranged more orderly and can quickly return to their original shape after being deformed by external forces. This improvement in elastic recovery ability allows the fabric to be restored to flatness in a short time even if wrinkles are generated during wearing, maintaining its beauty.

3. Reduce friction between fibers
Liquid ammonia treatment makes the fiber surface smoother and reduces friction between fibers. This smooth surface property makes it difficult for fibers to entangle and adhere when the fabric is squeezed or folded, thereby reducing the probability of wrinkle formation.

3. How liquid ammonia treatment improves the dimensional stability of fabrics

1. Enhance the crystallinity of fibers
The crystallinity of fibers refers to the proportion of the orderly arranged area inside the fiber. The higher the crystallinity, the stronger the stability of the fiber. Liquid ammonia treatment can promote the orderly arrangement of fiber molecular chains and improve the crystallinity of fibers. This increase in crystallinity allows the fiber to maintain its structural stability when the external environment (such as humidity and temperature) changes, thereby reducing the shrinkage or expansion of the fabric.

2. Improve fiber orientation
Fiber orientation refers to the degree of arrangement of fiber molecular chains in a certain direction. Liquid ammonia treatment can make the fiber molecular chains more orderly arranged in the direction of force, thereby improving the orientation of the fiber. This improvement in orientation enables the fabric to evenly distribute stress when stretched or compressed, avoid local deformation, and maintain overall dimensional stability.

3. Reduce fiber hygroscopic expansion
Some fibers (such as cotton fibers) will expand after absorbing moisture, causing changes in fabric size. Liquid ammonia treatment reduces the hygroscopicity of the fiber by changing the microstructure of the fiber, thereby reducing the degree of hygroscopic expansion. This feature allows liquid ammonia jersey fabrics to maintain stable size in a humid environment, making them suitable for making high-end clothing.