How does the structure of PE flat FDY yarn enable the product to achieve the unique texture of cooling to the touch, as well as good toughness and elongation?

The structure of PE flat FDY yarn achieves the unique texture of cooling to the touch, as well as good toughness and elongation through the synergistic effect of molecular chain flexibility, crystallization behavior, orientation and crystal phase structure.

The molecular chain structure of polyethylene is relatively regular and flexible. There are no aromatic rings, aromatic heterocycles, or side groups like benzene rings on its long chain. It is completely composed of -C-C- chains, and the chain segments move quite freely. This high flexibility allows the molecular chain to move and deform more easily. During the cooling process of the product, when the product is touched, this characteristic of the molecular chain may give people a unique texture of cooling. At the same time, high flexibility also provides a basis for the product to have good toughness and elongation, because the molecular chain can more easily absorb energy through deformation, thereby resisting fracture.
Crystallization behavior

Due to the relatively regular molecular structure and high flexibility of PE, the molecular chain can easily reduce the surface energy by folding and stacking each other to make the system more stable, thereby forming polymer crystals. The presence of crystallization has an important influence on the performance of PE flat FDY yarn. The crystalline region has high order and rigidity, which can provide certain strength and stability for the product; while the amorphous region has good flexibility and deformability, so that the product can withstand certain stretching and deformation.

The higher the crystallinity, the better. Although crystallization makes the molecular chain arrangement more regular, the connection between the crystalline region and the crystalline region is amorphous, and there are many defects. If the crystallinity is too high, the brittleness of the material will increase, and the toughness and elongation will decrease. In PE flat FDY yarn, it is necessary to control the appropriate crystallinity to balance the strength, toughness and elongation of the product.

FDY is a stretched yarn with a fully oriented structure obtained by a one-step method. Its molecular orientation is high, which is conducive to crystallization. Under the high stress of spinning, the crystallization starting temperature is high and the crystallization time is shortened. Due to the formation of orientation and crystalline phase structure, FDY has a high strength and a relatively low initial modulus. This feature allows the yarn to undergo low-tension heat setting on the hot roller, which is conducive to the product maintaining good toughness and elongation.

The oriented structure makes the molecular chains arranged along the fiber axis, improving the strength and modulus of the fiber. The appropriate crystal phase structure can give the fiber good toughness and elongation while ensuring a certain strength. When the fiber is subjected to external force, the oriented molecular chains and crystal phase structure can work together to effectively transmit and disperse stress, thereby resisting breakage and deformation.