Study On The Properties Of Polyester Fibre And Its Fabics

The PTT/PET bicomponent fiber has the unique advantages such as bulkiness and elasticity due to the self-crimp determining the good application on the textiles. However, there exist many problems about this fiber and fabric made by the fiber. So in the paper, we study the fiber of PET,PTT and PTT/PET bicomponent fiber. The main work is as followings:First, we use KE SI DA microscope for observing the appearance and configuration of bicomponent fiber. It was found in the bicomponent fiber it is a bilateral array for the PET and PTT. The cross section is anisomerous with PTT and PET side by side. After heat treating the shape of single filament becomes three dimensional curly and the number of crimp is biggest in the condition of relaxation. In the range of some tention, the bulkiness and crimpness fall obviously after the bicomponent fiber is treated with heat. When it exceeds the range of extension, the bulkiness and crimpness become high. Secondly, in the base of experiments, it is analyzed the affect of heating media,time,temperature and tension to the contractility of Polyester fibers. It is found that in the condition of the same tension and dry media, the contractility of PET,PTT and bicomponent fiber increases with the increasing of treating time and temperature. The bicomponent fibre has a steady contractility when the temperature is 140～160℃. In the condition of same tension and wet media, the contractility of PET,PTT and bicomponent fiber increases with the treating time and temperature. The contractility of bicomponent fiber has a nonlinear relation with the treating time. In the initial phase, the contraction increase rapidly and then slowly, after some time, about 10 minutes, it is near to steady. In the condition of the same wetting media or drying media,time and temperature, the contractility of PTT,PET decreases with the falling load. The curve of ratio of contractility presents hyperbola. When the tension<11.5mg/D, the decreasing is obviously as the tension increases. But when it is put in the opposite condition, the changing is not obviously.Thirdly, testing and analyzing the characteristics of the mechanical properties of polyester fibre and finding the typical stress - strain characteristic curve of PTT / PET composite fibre can be divided into six different tensile stages. The two flexible region and two plastic region in the curve are significantly different from PET fibres. In PTT / PET fibre with the increase of PTT component ,the curly elongate rate increased while the modulus declined gradually.In the conditions of hot air and 1 mg / D tension, with the temperature gradually rose from 100℃to 200℃, the rupture elongation rate of PET, PTT and PTT/PET fibres and the curly elongation rate of PTT / PET fibre are better than their original fibres, the fracture strength of PTT and PET fibre are better than their the original fibre, while the fracture strength of PTT / PET composite fibre is less than its original fibre. The modulus of PTT fibre increased with the increasing temperature while the modulus of PET fibre dropped significantly, and the modulus of PTT / PET fibre slightly increased with the increaseing temperature. On the conditions of hot air, no strain and the temperature gradually rose from 100℃to 200℃, the crimp elongation rate and breaking elongation rate of PTT, PTT / PET composite fibre increased with the increasing temperature, and are better than the original fibre. The fracture strength and modulus of PTT fibre increased with the increasing temperature, but they are less than the original fibre's. The fracture strength and modulus of PTT / PET composite fibre decreased with increasing temperature and they decreased significantly than the original fibre.In the conditions of hot water and no strain, at the same time, the breaking elongation rate and curly elongation rate of PTT / PET fibre increases with increasing temperature and better than the original fibre. The fracture strength and modulus of PTT/PET fibre decreased more than the original fibre without heat treatment. Temperature rose from 50°C 100°C, the breaking elongation rate of the three fibres are gradually increased and are better than the original fiber without heat treatment. The curly elongation rate of PTT / PET composite fibre decreased gradually with the increasing temperature, but better than the original fibre without heat treatment. The modulus of the three fibres decreased with increasing temperature, it decreased significantly compare to the original fibres, and the fracture strength of PTT/PET decreased more than the original fibre without heat treatment, the fracture strength of the three fibres showed downtrend while the temperature increasedUnder hot air treatment condition, the crimp elongation rate and rupture elongation rate of bicomponent PTT/PET fibre all declined exponentially with increasing tension. The modulus under small tension and fracture strength all changed significantly and when the tension was larger than a critical value, the modulus and elongation at break were nearly constant. Besides, compared with the untreated fibres, the modulus of the two single-component fibres were decreased to some extent and they all increased with increasing tension.At last, it is discussed the property of PTT/PET biocomponent fiber/wool fiber blended fabric. It is analyzed the different factors affecting the elasticity. It is found the elasticity of fabric increases with the ratio of bicomponent fiber to PTT. In the proper twist, the elasticity can be promoted. The breading load and elongation at break increase with the twist, and the way of weaving has no affect to the elasticity. The mechanic property of PTT/PET bicomponent fabric with Dope dyeing and fabric with no dyeing has no differences. After relaxation, the elasticity of dyeing fabric is better than the fabric with Dope dyeing and fabric with no dyeing; the elasticity of fabric treated with relaxation is better than the fabric treated with framing setting. The modulus and breading load increase with size of fiber. When the size of fiber is big, the fabric is not transformed easily, but the restoration is better than the fabric with small size of fiber.