What are the reasons for the reduction of the tensile strength of cotton and linen in the tensile strength dyeing and finishing process?

1. Chemical damage, such as chlorine bleaching, oxygen bleaching, peeling, flame retardant finishing (fiber carbonization), acid action, enzyme action, etc.

2. Physical damage, such as sanding.

3. Cross-linking, such as the cross-linking of anti-wrinkle finishing, causes the stress of the fabric to be concentrated, and the stress cannot be uniformly dispersed, resulting in a decrease in the tensile strength data (of course, there is also chemical damage to the fiber by acid in the anti-wrinkle finishing). However, after finishing with resin, the strength of rayon fabric does not decrease, but rises instead (see picture). The principle is that the fracture mechanism of rayon is different from that of cotton and linen. The main reason for rayon's fracture is the mutual slippage of its chain segments. , And the generation of cross-linking can just overcome this slippage and increase its tensile strength

4. Softening, the influence of softening on stretching has not been paid much attention, because this drop is actually relatively small. According to the quantitative research data on cotton twill, it will generally only drop by a few percent, and the maximum will not exceed 15%. The reason for the decrease in tensile strength is that the addition of softener makes the cohesive force of the yarn worse, making it easier for the fiber to "slip" out of the twisted yarn under stress. From this, several speculations that can be obtained are:

a. Silicone oil with higher slippage will damage the tensile strength of the fabric more than the soft sheet with lower slippage;

b. Micro-emulsion silicone oil has greater damage to the tensile strength of fabrics than giant-emulsion silicone oil;

c. The shorter the fiber of the fabric, the lower the twist, and the more easily its tensile strength is damaged by soft oil. Softening has almost no effect on the tensile strength of long-staple cotton fabrics, but may have a greater effect on linen fabrics.