Acrylic is more expensive. Polyester refers to polyester, acrylic fiber is expensive, and acrylic fiber is nearly twice as expensive as polyester. The structure and properties of polyester fiber mainly depend on its molecular chain structure and aggregated structure. The molecular chain structure determines the chemical stability and thermal stability of polyester fiber, while the aggregated structure determines the physical and mechanical properties of polyester fiber. The advantages are wear resistance, wrinkle resistance, air permeability and moisture removal. It is suggested to use polyester fiber fabric as summer clothes, which can be more refreshing. Acrylic fiber Jοnglún, the scientific name of polyacrylonitrile fiber, is called "Oren" and "cashmere" abroad. Acrylic fiber is a kind of synthetic fiber, which is white in appearance, curly and fluffy, soft to the touch, bright in color, light-resistant, antibacterial and moth-proof, and looks like wool. Often blended with wool or used as a substitute for wool, it is also called "synthetic wool".