Poly ethylene terephthalate fiber is the most important industrial fiber in textile manufacturing. The rate of production and consumption of this fiber is so high that in the last years of 20’th century, its contribution of total world fiber production increased to 36%. Because of increasing trend of consumption of PET fibers, the wide range of projects and activities to improve the properties of this product, has been defined. In this research, the investigation of structure and trying to production of some commercial poly ester fiber has been done. PAN-like poly ester fiber is the new type of modified fiber that said it can be replaced with PAN fiber in its application. Using of some equipment such as nuclear magnetic resonance (NMR) and elemental analysis (CHNS), the comparison of chemical structure of the commercial PAN-like polyester fiber with usual PET fiber has been done. Structure of Pan-Like polyester fiber and CD-PET fiber has been investigated by X-ray diffraction. Thermal behavior of PAN-Like polyester fiber, CD-PET and commercial polyester has been compared by differential scanning colorimeter (DSC). Dying properties of PAN like polyester fiber has been compared with commercial PET fiber in disperse and cationic dying procedure. After the melt spinning process and production of some BCF yarns with some PAN-like PET chips, the dying, weight reduction, and moisture absorbent of fibers has been compared. With increasing the share of modified PET chips in poly blend fiber, increasing of dying process efficiency can be achieved. The dying process of modified PET fibers can be done in boiling temperature of dying bath and about 25 centigrade less than usual dying procedure of PET fiber. The result show that, with increasing the share of modified PET chips in poly blend fiber, the rate of alkaline hydrolysis and related weight reduction of final product, have some ascending trend. Key Words: PET Fiber, CD-PET Fiber, PAN like Polyester Fiber, Melt spinning, Weight Reduction, Dying
