Research On The Effect Of Preparation Conditions On Spandex Properties And Safety Analysis Of Its Preparation And Use

Spandex is a common synthetic fiber, it has been widely applied in apparel, textile, sports equipment and even some areas of the medical field. Some accidents happen due to its mechanical failure when Spandex is used. In order to improve this situation essentially and achieve the intrinsical safety of spandex material, we prepared three different series of spandex by changing three dry-spinning spandex production conditions, include the draw ratio, the wind amount of corridor and the temperature of corridor. The main research is as follows:(1) Selected PTMG, MDI as starting materials, EDA as chain extender and DMAc as solvent, prepared 12 group spandex samples by changing the draw ratio, the wind amount of corridor and the temperature of corridor.(2) Selected 12 groups spandex, using Fourier transform infrared spectroscopy to characterize its structure, X-ray diffraction test measured the degree of crystallinity, universal testing machine to test the mechanical properties, studied the effects of different preparation conditions on the microstructure and mechanical properties of spandex. The results showed that: when the draw ratio increased from 1.05 to 1.2, the elongation at break declined while the breaking strength increased, 300% elastic recovery first increased then decreased, when the draw ratio is 1.1, spandex 300 % elastic recovery rate reached a maximum. When the wind amount of corridor increased from 630 m3/h to 750 m3/h, the elongation at break added, breaking strength declined while 300% elastic recovery rate added. When the temperature of corridor increased from 242℃ to 250℃, the elongation at break increased, breaking strength declined, 300% elastic recovery first increased then declined, when the temperature of corridor reached 248℃, the spandex 300% elastic recovery rate reached a maximum.(3) Selected 12 groups spandex, used universal testing machine to test the stress relaxation properties of spandex. Studied the influence of different preparation conditions on the stress relaxation rate of spandex, Spandex stress’ s variation with time within three hours, the influences of fixed rate of elongation and tensile rate on stress relaxation properties of spandex, the results showed that: the draw ratio, the wind amount of corridor and the temperature of corridor had no effect on spandex’s GB stress relaxation rate. When stress relaxation time was extended to 3 hours, the stress experienced three phases: a rapid decline then a steady and slow decline and finally tend to be relatively steady-state value. In the case of a given elongation is less than 300%, the elongation had no significant effect on the stress relaxation properties of spandex. When stretching rate was less than 500mm/min, stretching rate had no effect on the of stress relaxation properties of spandex. In order to maximize the elimination of the negative effects caused by stress relaxation, we’d better to stretch spandex and keep at least 3h then use it.(4) Improve the security of spandex manufacturing process by identificating the hazards in the process of dry-spinning spandex production then proposing specific measures to solve them. Selected the elongation at break, breaking strength, elastic recovery rate of 300% and energy consumption during the preparation for the safety evaluation, when the draw ratio is 1.1, the wind amount of corridor is 690 m3/h and the temperature of corridor reached 244℃, the spandex’s properties were best.