| Polyglycolic acid（PGA）is biodegradable,flexible and biocompatible,and has a broad market prospect in the field of degradable fiber and film products.It has been widely used in the field of absorbable surgical sutures.However,the disadvantages of PGA products,such as fast degradation,harsh storage conditions and short shelf life,restrict its large-scale promotion and application.Modification of PGA material or coating of retarded degradation agent on the surface of suture line is the main method to adjust the degradation time and prolong the degradation cycle of PGA products,but there are also limited adjustment range and complex processing problems.Poly（Llactide）（PLLA）has good bioabsorbability and biocompatibility,and its performance is stable,easy to preserve,strength is stable,harmless to human body,is a typical representative of degradable materials,has been widely used in fiber,film,medical suture and orthopedic materials.Using twocomponent composite fiber preparation technology,PLLA and PGA are combined,and the degradation performance of PGA fiber can be controlled by adjusting the composite ratio and the composite way by taking advantage of their respective advantages.This paper proposes a method to prepare sheath-core fibers with different composite proportions by using PLLA with long degradation cycle as the cortex,so as to realize the regulation of degradation time of PGA fiber products and improve the degradation cycle of PGA fiber.Degradable fibers with different PLLA/PGA sheath-core composite ratio were prepared by composite spinning method,taking advantage of the long degradation cycle of PLLA,and the effects of sheath core composite ratio and processing technology on fiber degradation cycle were studied by accelerated degradation method.The results showed that:（1）It was found that the skin core section of the composite fiber prepared at 245 ℃ was in good shape;The breaking strength of PLLA/PGA composite fiber increases with the increase of PGA content;When the composite ratio is 20/80,the drafting temperature is 80 ℃,the drafting ratio is 4.5 times,and the heat setting temperature is 130 ℃,the mechanical strength of the composite fiber is the best.（2）For fibers with a certain drafting temperature and heat setting temperature,the degradation rate gradually slows down with the increase of drafting multiple;The degradation rate of fibers with heat setting temperature of 130 ℃,drafting temperature of 4.5 times and drafting temperature of 80 ℃ is the slowest.（3）The study on the degradation performance of composite fibers with different aggregate structures found that the fiber samples with high crystallinity,grain size and crystal orientation of the two components had the lowest weight loss rate and high strength retention after degradation in phosphate buffer at 70 ℃ for 24 hours.（4）After 24 hours of degradation under the same conditions,PLLA/PGA fibers with a composite ratio of 20/80 have better strength retention than pure PGA fibers.In this paper,the sheath core composite method is used to extend the degradation cycle of PGA fiber,which provides a new idea for the development of fiber products with controllable degradation performance,and is helpful to support the popularization and application of degradable PGA materials. |
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