关键词: 聚己二酸/对苯二甲酸丁二醇酯, 熔体离心纺丝, 微纳米纤维, 纤维直径, 纺丝参数

Abstract: Poly(butylene adipate-co-terephthalate) (PBAT) is a widely available biodegradable polymer that combines the excellent biodegradability of aliphatic polyesters with the good thermal and mechanical properties of aromatic polyesters. It is commonly used in food packaging and films due to its good elongation and degradability. Its excellent degradable properties have the potential to solve the problem of fiber waste disposal. However, there are still many problems in the preparation of PBAT fibers: the low flow properties and high elasticity of PBAT melt make it difficult for the jet to stretch and refine and coil to form fibers; the presence of flexible butylene adipate(BA) units makes it difficult for PBAT fluids to crystallize rapidly during the curing process.
Melt centrifugal spinning, with the advantages of high yield, low energy consumption and wide choice of raw materials, is a good choice for the preparation of micro and nano fibers. The shear force brought by high-speed rotation can effectively enhance the fluidity of PBAT and the effect of centrifugal force can reduce the curling of fibers. Therefore, to further expand the application of PBAT in flexible electronics, high efficiency filtration, pharmaceutical loading and other fields, the spinnability of PBAT under melt centrifugal spinning process was explored by using self-designed melt centrifugal spinning equipment, and the influence law of extruder temperature, spinner temperature, motor speed and collection distance on fiber morphology was explored through orthogonal tests to obtain the best spinning process parameters. Meanwhile, according to the orthogonal test results, further analysis of extruder temperature on fiber structure and legal properties was carried out. The results show that: in the process of melt centrifugal spinning, increasing the spinning temperature will cause the polymer melt viscosity to decrease, and the shear force brought by the high speed rotation of the motor can also cause the polymer melt viscosity to decrease; in the process of melt centrifugal spinning, the most important influence on the fiber morphology is the extruder temperature and motor speed, followed by the collection distance, with the spinner temperature having the least influence. The best spinning requires a temperature of 220 ℃, a motor speed of 4,000 r/min, a collection distance of 18 cm, and a spinneret temperature of 200 ℃. Increasing the spinning temperature can effectively avoid fiber curl, significantly refine the fiber diameter; with the increase of temperature, the polymer viscosity decreases, fluidity becomes better, the prepared fiber distribution is more uniform, the fiber film is more-dense under the winding and stretching of the conveyor belt, the maximum stress of the fiber film increases to 15.3 MPa, and the maximum strain reaches 80%. The above results show that PBAT has excellent spinnability in the melt centrifugal spinning process, and PBAT fibers can be prepared by using lower temperatures compared to several other PBAT melt spins due to the decrease in polymer melt viscosity caused by temperature shear from high-speed rotation.
Melt centrifugal spinning has good spinnability for PBAT and is also well suited for other poorly flowing polymers. The results of this study provide reference for the industrialization of melt spinning.

Key words: poly(butylene adipate-co-terephthalate), melt centrifugal spinning, microfiber, fiber diameter, spinning parameters