Most of these fibers come from the synthesis of petrochemicals. The macromolecular chains are mainly lipophilic organic groups, lacking a certain number of strong polar groups (such as -OH, -NH, C=O, etc.). It is difficult to form hydrogen bonds with water molecules, and has similar compatibility with various oily molecules (vegetable oil, mineral oil, plastics, etc.). The proportion of the crystalline area is larger, the amorphous area is less, and the molecular structure is relatively tight. It is difficult for water molecules to penetrate into the voids inside the fiber.
However, due to the hydrophobicity of these fibers, it also brings shortcomings in the wearing performance, that is, the wearing is stuffy, airtight, not soft, and the comfort is poor. Therefore, the modern textile industry uses the method of blending or interweaving hydrophilic fibers and hydrophobic fibers to complement each other.