| Abstract: | The effect of modifying monomer sodium 3,5-di(carbonethoxy)benzene sulfonate] contents range from 1.5 to 4.5 mol % on the melt flow and fiber properties of copolyesters (COPET) dyeable with basic dyes was investigated. An Instron capillary rheometer was used to obtain data over shear rates ranging from 10 to 104 s?1 at 265, 275, and 285°C. The COPET's flow properties as a function of temperature, inherent viscosity, melting point, and modifying monomer content were determined. The drawn fibers annealed in oil and air at 80, 110, 130, 150, 175, and 200°C were studied by means of measurements of shrinkage ratio, crystallinity, birefringence, long period, sonic rate, and static state flexibility of molecular chain. All these showed that the large side group, ? SO3Na in COPET molecular chains causes an increase in chain rigidity and melt viscosity, and a decrease in crystallinity and orientation. |
