Studies On The Preparation Of Biodegradable Poly (Butylenes Succinate-co-butylene Terephthalate)(PBST) Fibers And Its Elasticity

As requirements of comfort increase, elastic fibers (such as polyurethanes, polyether esters, polyolefin, composite curly bi-component fibers, etc.) are more and more popular, and its application field also expanded from traditional knitting production, underwear, sportswear etc to the casual wear, elastic fashion, high-grade garments and other emerging field, and continue to the automobile decoration field, medical field.As the wide application of Elastic fibers for improving quality of people's life, its waste (elastic fiber lose efficacy easily after repeated use) cause environmental pollutions because of non-biodegradable of most elastic fibers. Therefore, the development of new biodegradable elastic fiber is imperative. Usually the biodegradable fibers, such as polylactic Acid (PLA), poly glycolic acid (PGA) fiber and etc, are aliphatic polyester fibers, but this kind of fiber have many shortcomings, such as poor thermodynamic performance, higher cost and etc, therefore have less application in textile industry. But aromatic polyester fiber, such as PTT and PBT fiber, all have a good physical process performance and good flexibility. Therefore, biodegradable aliphatic-aromatic co-polyesters possessed good biodegradability and mechanical properties became more and more attractive. Poly(butylenes succinate-co-butylene terephthalate)(PBST) fiber and relevant work put forward based on this background.In this paper, PBST fully drawn yarn(FDY) was spun by one-step high-speed melt spinning process, effects of different spinning process parameters on structure and performance of PBST FDY fibers was discussed; PBST false twist stretch yarn(DTY) was prepared by the process of pre-orientation yarn (POY) to false twist deformation yarn(DTY), effect of the false twist process parameters on the structure and properties of PBST false twist yarn(DTY) studied; The PBST FDY fibers was then heat setting, effect of heat setting process parameters on structure and properties PBST FDY fibers was studied, providing theory basis for application of PBST fibers.First of all, the PBST FDY fibers was spun using one-step melt spinning process, the PBST FDY spinning process was studied and optimized. Research results showd that spinning optimum temperature of PBST resin is between 240 and 260℃, PBST fiber tensile properties and elastic recovery increased with the spinning speed, and drawn ratio and deformation temperature. And boiling water shrinkage properties of PBST fibers are also improved. In addition, PBST fiber best cooling conditions was 24-26℃of quench air temperature,0.4-0.6 m/s of wind speed,65 - 70% of humidity. Japanese Zhuben F-1048 spinning oil was chose, result showed that tow hold close have better effect, the glabrous fiber phenomenon was basically disappeared, and have good winding shape.Secondly, PBST DTY fibers was spun using a pre-orientation yarn (POY products) to false twist yarn(DTY) process. Research results showed that tensile curves of PBST DTY fibers have a linear shape in the whole tensile process, similar to the spring. And with the higher drawn ratio (DR), PBST fibers crystallinity and molecular orientation increased, the breaking strength and elongation at break also increases, boiling water shrinkage decreased accordingly, When draw ratio was 1.22, deformation temperature was 190℃, textured temperature of 160℃, winding speed per twisting speed (D/Y) was 2.0, PBST fiber have bigger curl, fully appearance.Thirdly, heat setting of PBST FDY fiber was carried out. Results show that PBST fiber was processed instantaneously by relaxation and tensile dry-heat setting. Compared to the time of heat setting parameters, heat setting temperature is more important. After relaxation, tensile heat setting, elasticity recovery of PBST fiber declined obviously, and the PBST fibers after relaxation heat setting have lower elastic recovery than tensile heat setting.This shows structure of high-speed melt spinning PBST FDY fibers is neat, in heat setting processing process, between two contrary aspect of crystallization and disorientation, the disorientation was more dominant, thus leading to decreasing of elastic recovery of PBST fiber.In addition, comparing of the tensile properties of PBST fiber fiber and other fibers shows that tensile curves of PBST and PBT fiber are very similar, but compared to PBT fiber, PBST fiber have higher elongation at break and breaking strength. Strain rate, repetitive stretching times and elongation all affect elastic recovery behaviors of PBST fiber. And PBST fiber elastic was very outstanding, even at 20% of elongation, repeat 5 times, can still keep 88% of the elastic recovery rate, In order to describe PBST fiber stress relaxation and creep behavior more visually, the viscoelastical mechanical model of PBST fiber was established, the results showed that the simulation was very successful, correlation coefficient can reach 0.98 above; Elastic mechanism of PBST fiber was explained by the crystal structure changes of PBST fiber in the tensile process. The crystal transition from a-form toβ-form of PBST fiber in tensile process was found as similar to PBT fiber. Critical elongation of PBST fiber crystal transition was longer than PBT fiber.α-form crystal still exist at elongation of 25% endows that PBST fiber has higher elastic recovery rate.