As we all know, the various properties of cotton fiber are directly related to the quality of cotton yarn products, and there are many factors that affect fiber performance, such as seed selection, picking methods, processing procedures, processing environment, etc., which may affect the various properties of cotton fiber. This article is with you Share some of the main indicators that temperature and humidity affect cotton fiber.
1. Effect on moisture absorption performance of cotton fiber
In production, moisture regain is mostly used to measure the fiber’s hygroscopicity. The factors that affect fiber moisture regain are divided into internal factors and external factors. The internal factors mainly depend on the number of hydrophilic groups in the fiber macromolecules and the strength of the hydrophilicity, the crystallinity of the fiber and the size and number of voids in the fiber. Cotton fiber is a porous material, and there are There are many hydrophilic groups (—OH), so it has good hygroscopicity. External factors include the surrounding air environment, storage time and moisture absorption and dehumidification process, among which air temperature and humidity are the most important. The relative humidity of the surrounding air is high, and the fibers absorb more moisture. When the relative humidity is constant, the hygroscopic performance of the fiber decreases as the temperature increases. If the fiber moisture regain is to be maintained at a constant value, the relative humidity should be slightly larger when the air temperature is high, and the relative humidity should be smaller when the temperature is low.
2. Effect on cotton fiber strength
Among the various physical properties of fibers, humidity is closely related to fiber strength. As the humidity of the cotton fiber increases, the alignment of the long molecular chains is promoted and improved, thereby increasing the strength.
3. Effect on cotton fiber elongation and softness
Textile fibers and products are subject to external stretching during processing or use, and produce corresponding elongation and deformation. The fiber after absorbing moisture is prone to relative displacement due to the increase in the distance between molecules, so the elongation of the fiber increases with the increase in relative humidity. Temperature has little effect on elongation.
In terms of softness, as the relative humidity increases, the distance between the molecules of the fiber increases after absorbing moisture. Therefore, the softness of the fiber increases, the hardness and brittleness decrease, and the plasticity and elastic recovery decrease. Because cotton fiber has cotton wax on its surface, it is particularly sensitive to changes in temperature and humidity. When the temperature is high, the cotton wax softens, making the cotton fibers softer. If the temperature is too high, the cotton wax will begin to melt and become sticky, and the fibers will wrap around the rubber roller, affecting production quality. When the temperature is too low, the cotton wax will harden, causing the fiber to lose its softness and become brittle, which will adversely affect the spinning process.
4. Effect on the conductivity of cotton fiber
Cotton fiber is a poor conductor of electricity. During processing, friction with the mechanical surface or fibers generates static electricity, which causes the fibers to be adsorbed on the surface of the machine parts, hindering the smooth flow of fiber drafting, carding, and winding processes, and affecting the quality of the yarn. In order to reduce this adverse effect, for fibers with certain hygroscopicity such as cotton fiber, the method of increasing the relative humidity can be used to increase the moisture regain of the fiber and enhance the conductivity of the fiber. As the temperature rises, the electrical conductivity of the fiber will increase accordingly. However, if the temperature is too high, the cotton wax will melt and winding of rubber rollers and rollers will easily occur, affecting production.
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