Preparation And Properties Of High And Low Viscosity PET Side-by-side Component Fiber

The side-by-side component fiber is prepared by two polymers,which has different structures and performance,so this fiber has a three-dimensional spiral structure,and have a wide application in the elastic fabrics,bedding,ect.The development of PET/PTT bi-component fiber has important and experienced period with increased productions according to the current studies.However the production' costs and competition have certain disadvantage,because of higher price of PTT raw materials.The study used two kinds of polyethylene terephthalate(PET)with different viscosity,PET side-by-side bi-component fiber was obtained by melt spinning with twin screw extruder.Molecular structures,thermal properties and rheological properties of two kinds of PET were studied systematically.The effects of two-ratio and spinning drafting process on fiber morphological structure and properties were discussed.And the high shrinkage,mechanical properties,morphology and crimp properties were studied detailed.It provides a certain reference for the development and productionFirstly,the structure and properties of the raw materials were studied by characterization methods like H-NMR,DSC and Capillary rheometer.The test results show that,The intrinsic viscosity of both materials are 0.908 dl/g and 0.502 dl/g,The melting points of high viscosity PET and Low viscosity PET are 254.4 ? and 250.8 ?.The weight loss temperature both around 400 ?,they have good thermal stability.The composition and content of the comonomers are the same,they are both terephthalic acid(PTA)and ethylene glycol(EG).Rheological properties testing results show that rheological properties of high viscosity PET are better than Low viscosity PET,and they are typical non-Newtonian fluid.The results of research on the structure and properties of high-low viscosity PET side-by-side composite fiber show that the ratio 70:30,60:40,50:50,40:60,30:70 of high-viscosity PET/low-viscosity PET,During the process,the orientation degree of the composite fiber decreases,the degree of crystallization rising,the tensile strength,elongation at break,and wet heat shrinkage decrease.The drafting process has great influences on structure and properties of fiber.With the increas of draft ratio or weaken of heat setting temperature,the orientation and crystallization of composite fiber fortify,but the breaking strength was enhanced gradually.Nevertheless elongation and wet heat shrinkage decrease.By studying the structural performance of the two modeling fibers and the vertical and horizontal distribution of two s of colored composite fiber,the highviscosity PET has the structure of high-orientation but the structure of lowcrystallization when the low-viscosity PET has a low-orientation and highcrystallization structure.Lead to high-viscosity is a high-shrinkage part.The crimp properties of fiber were researched,when the composition ratio of 50:50,the fiber has better potential crimp properties,crimp ratio,crimp modulus,and crimp stability reach 22.64 %,7.21 %,32.97 %,respectively.And at the composite ratio(50:50),crimp properties decrease with higher drafting ratio and heat-setting temperature.The results showed that hot-shrinkage rate between the two of the side-by-side composite fiber is gradually reduced.With the increase heat annealing temperature,the crimp properties of side-by-side composite fiber increase initially,and decrease afterwards.Maximize at 180 ?.At the same heat treatment temperature,longer heat treatment time can improve the crimp properties of the composite fiber.The studies contribute to the treatment in commercial application.