Pet / pcl / pbt ternary composite hollow fiber for artificial blood vessel framework and preparation method thereof

Abstract

The application belongs to the field of textile fibers and fiber material preparation, and particularly relates to PET / PCL / PBT ternary composite hollow fibers for artificial blood vessel framework and a preparation method thereof. The PET / PCL / PBT ternary composite hollow fibers for artificial blood vessel framework are prepared from a spinning solution prepared from a mixed solution of PET, PCL and PBT. The hollow fibers have a multi-level structure with a macroporous network and micropores coexisting. The macroporous network is a loose macroporous structure with uniform pore size connected by film curling substances. The inner wall of the pores is in a smooth and continuous state. The surface of the fibers has a wrinkle topological morphology distributed along the axial direction. The PET / PCL / PBT ternary composite fibers are prepared by using a dry-jet wet spinning method. A non-solvent phase separation is used to construct the porous structure of the fibers. By controlling the spinning solution composition of the shell, the feeding sequence, the spinning solution flow rate and the coagulation bath and other dry-jet wet spinning process parameters, the controllability of the fiber morphology and performance is realized.

Description

Technical Field

[0001] This invention belongs to the field of textile fibers and fiber material preparation, specifically relating to PET / PCL / PBT ternary composite hollow fibers for artificial blood vessel structures and their preparation methods. Background Technology

[0002] Natural blood vessels are hollow tubular organs with an inner lumen. Hollow fibers, due to their similar structure, have become the core material for artificial blood vessel architecture. In particular, small-diameter (inner diameter < 6 mm) artificial blood vessels place extremely high demands on the mechanical properties, blood compatibility, and biocompatibility of hollow fibers, making them a key focus and challenge in the clinical translation of artificial blood vessels.

[0003] Currently, polyethylene terephthalate (PET) is a commonly used substrate for artificial blood vessel fabrication due to its good chemical stability, low cost, and wide availability. However, its molecular chain is highly rigid, and hollow fibers made from pure PET suffer from high brittleness, poor tensile properties, and a mismatch between mechanical compliance and natural small-diameter blood vessels. Furthermore, traditional wet spinning tends to form a predominantly finger-like pore structure with uneven pore distribution, low axial tensile strength, and a tendency to crack along the pores under dynamic stress. Dry spinning, on the other hand, forms a dense, non-porous structure with low porosity and poor endothelialization. To improve the performance defects of pure PET, existing technologies use a binary blend of PET and polycaprolactone (PCL) to prepare composite hollow fibers. The excellent flexibility and biocompatibility of PCL are used to toughen and modify PET. Simultaneously, by combining dry-jet wet spinning with the principle of non-solvent-induced phase separation, the finger-like pore structure of PET is controlled to a sponge-like pore structure, achieving a certain optimization of fiber toughness and pore structure, thus solving some of the problems related to the high brittleness of pure PET.

[0004] However, existing PET / PCL binary composite hollow fibers still have many technical shortcomings, making it difficult to meet the clinical application needs of small-diameter artificial blood vessels: First, the binary system only achieves a simple combination of rigidity and flexibility. The toughening effect of PCL leads to a loss of material strength, insufficient creep resistance, and limited radial mechanical strength. Second, the porous structure formed by binary blending is still a single type of sponge pore, with limited improvement in porosity. Moreover, the fiber surface is smooth and lacks specific morphology, making it difficult to simulate the extracellular matrix structure of natural blood vessels and resulting in a weak promoting effect on endothelial cell adhesion and proliferation. Third, the binary system has not been specifically optimized for the blood compatibility of small-diameter artificial blood vessels. Although it has basic biocompatibility, there is still a potential risk of acute thrombosis.

[0005] In addition, polybutylene terephthalate (PBT), as a rigid-chain engineering plastic, has a similar structure to PET and complementary mechanical properties. It has excellent creep resistance and modulus characteristics. However, when used alone in artificial blood vessels, it has problems such as low elongation at break, poor blood compatibility, and poor operational adaptability.

[0006] In summary, existing technologies cannot simultaneously meet the multiple core requirements of small-diameter artificial blood vessels for skeletal strength, flexibility and compliance, creep resistance and stability, excellent blood compatibility and efficient endothelialization. There is an urgent need to develop a new composite hollow fiber preparation technology, which can comprehensively improve material performance through the rational combination of components and precise optimization of processes, and promote the clinical translation and application of small-diameter artificial blood vessels. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a PET / PCL / PBT ternary composite hollow fiber for artificial blood vessel architecture, which can simultaneously meet the multiple core requirements of small-diameter artificial blood vessels for scaffold strength, flexibility and compliance, creep resistance and stability, excellent blood compatibility and efficient endothelialization.

[0008] This invention also provides a preparation method for PET / PCL / PBT ternary composite fibers, which are prepared by dry-jet wet spinning, using a solvent-free phase separation method to construct a porous fiber structure. By controlling the composition and feeding sequence of the spinning solution, the flow rate of the spinning solution, and the coagulation bath, etc., the morphology and properties of the fibers can be controlled.

[0009] The PET / PCL / PBT ternary composite hollow fiber for artificial blood vessel architecture described in this invention is made from a spinning solution prepared from a mixed solution of PET, PCL and PBT. The hollow fiber exhibits a multi-level structure in which macroporous networks and micropores coexist, with a porosity of 65%. Specifically, the macroporous network is a loose macroporous structure with uniform pore size connected by a thin film-like rolled material, and the inner wall of the pore is smooth and continuous. The fiber surface exhibits a wrinkled topology distributed along the axial direction.

[0010] The method for preparing PET / PCL / PBT ternary composite hollow fibers for artificial blood vessel architecture according to the present invention includes the following steps: (1) After mixing PBT with solvent evenly, add PET and PCL and mix evenly to obtain a ternary mixed solution as the outer shell liquid, and let it stand to degas; (2) The outer shell liquid and the inner core liquid are placed into the syringe, connected to the coaxial needle (outer diameter 6mm, inner diameter 4mm), and placed into the spinning equipment. The coagulation tank containing the coagulation bath is placed below the coaxial needle, and an air section is set between the end of the needle and the coagulation bath. (3) Start the spinning equipment so that the outer shell liquid and the inner core liquid enter the coagulation bath of the coagulation tank through the air section, and then be drawn to obtain nascent fibers. After standing in the coagulation bath for 60-180 seconds, collect them. (4) Place the collected fibers in a water bath to remove the solvent completely. Then, use a syringe to inject water into the fiber pores to remove the spinning core liquid, thus obtaining PET / PCL / PBT ternary composite hollow fibers.

[0011] During the experiment, it was found that when equal amounts of PET, PBT, and PCL powders were dissolved in 20 ml of HFIP, the PBT solution became transparent the fastest. Therefore, PBT was added first. After adding PBT, it quickly clumped together. Once it dissolved and became uniformly transparent, other substances were added without clumping.

[0012] The nascent fibers obtained from drawing must first be placed in a coagulation bath, and then in a water bath. HFIP solvent is miscible with water and alcohol. Upon entering the coagulation bath, the solvent rapidly diffuses from the shell layer outwards and is carried away by the coagulation bath, causing the shell liquid to solidify and form a stable hollow fiber outer wall. Simultaneously, the core liquid gels, providing stable mechanical support to the shell layer, preventing the hollow structure from collapsing, completing phase separation and structural stabilization. The shell layer transforms from a "concentrated solution state" into a solid porous / dense membrane structure, and the fiber's outer diameter, wall thickness, and cross-sectional morphology are essentially fixed in the coagulation bath. If removed directly without allowing it to stand, both the inner and outer layers of the fiber will be in a soft state, resulting in an unstable structure and a tendency for fiber adhesion or even breakage.

[0013] In step (1), the PET concentration in the outer shell liquid is 8wt.%-10wt.%, and PCL is a flexible material. Too much PCL will cause the fiber to lose its basic mechanical support and cannot be formed. The concentration of PCL is 2wt.%-6wt.%; the PBT concentration is selected between 2wt.%-6wt.%. Too much PBT will also cause the fiber to be unable to be formed.

[0014] The number-average molecular weight of PET in step (1) is 20,000-40,000, preferably 30,000-40,000. The number-average molecular weight of PCL is 40,000-60,000, preferably 50,000-60,000, and the number-average molecular weight of PBT is 20,000-40,000, preferably 30,000-40,000.

[0015] The inner core liquid in step (2) is a mixture of sodium alginate and water. The concentration of sodium alginate in water is 2wt.%-7wt.%, preferably 4wt.%-6wt.%. If the concentration is too low, it cannot play an internal support role. If the concentration is too high, the spinning process will be difficult.

[0016] The coagulation bath in step (2) is a mixture of ethanol and water, with the volume concentration of ethanol in the water being 55-70%.

[0017] In step (2), a layer of sodium alginate solution is laid at the bottom of the coagulation tank to prevent the nascent fibers from directly contacting and adhering to the bottom, which could lead to damage to the skin layer.

[0018] The height of the air section in step (2) is 1-2 cm, preferably 1 cm. If the air section is too long, the spinning solution will be stretched by gravity after being squeezed out of the needle, resulting in excessively fine fibers and insufficient internal support.

[0019] In step (3), the flow rate of the outer shell liquid is 2-3 ml / min, and the flow rate of the inner core liquid is 2-3.5 ml / min.

[0020] The time for standing in the water bath in step (4) is 3-15 hours, preferably 8-12 hours. During the standing process in the water bath, the water is changed every 4 hours, and the number of times water is introduced into the fiber pores for rinsing is 3-8 times, preferably 4-6 times.

[0021] The solvent in step (1) is preferably hexafluoroisopropanol. Step (1) specifically involves placing the solvent on a stirrer and adding PBT powder during the rotation process. The PBT powder in the solvent will clump together. If other substances are added at this time, they will adhere to the clumps. Therefore, PBT should be dissolved first, and other substances should be dissolved later. In the end, the spinning solution will be more uniform.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: 1) This invention innovatively introduces PBT to construct a PET / PCL / PBT ternary blend system. Utilizing the structural similarity between PET and PBT to achieve mechanical complementarity, and combining this with the flexibility and toughening properties of PCL, PET provides skeletal strength, PCL imparts flexibility and compliance, and PBT enhances creep resistance and stability—all three work synergistically. The creep resistance and modulus advantages of PBT precisely compensate for the strength loss caused by PCL toughening, completely solving the technical pain points of easy deformation and insufficient radial support under long-term dynamic loads in binary systems. This allows the composite fiber to simultaneously meet the triple core requirements of strength, flexibility, and creep resistance for small-diameter artificial blood vessels, providing stable and durable structural support for them.

[0023] 2) This invention relies on the compatibility differences of the PET / PCL / PBT ternary components to drive multiphase separation, and the resulting composite fiber forms a multi-level porous structure in which macroporous networks and micropores coexist, increasing the porosity to over 65%. This ensures efficient nutrient penetration and provides a three-dimensional space for cell adhesion and proliferation. At the same time, the fiber surface naturally forms axially distributed wrinkled topology, which can accurately simulate the extracellular matrix structure of natural blood vessels, significantly promoting endothelial cell adhesion and proliferation. This solves the problems of smooth surface and low endothelialization efficiency of binary composite fibers, greatly improving the biocompatibility of composite fibers with the human body and reducing the risk of intimal hyperplasia.

[0024] 3) The ternary composite fiber of this invention maintains an axial tensile stress comparable to that of the binary system, while significantly increasing the radial tensile stress to 13N and precisely controlling the circumferential strain to below 3%. Its mechanical compliance is highly matched with that of natural small-diameter blood vessels, effectively resisting dynamic fluid pressure within the blood vessel and solving the defect of limited radial mechanical strength in the binary system. At the same time, the fibrinolysis rate is as low as 3.2%, which meets the ISO 10993-4 international standard. Blood compatibility is further optimized compared to the binary system, which can effectively reduce the risk of clinical complications such as acute thrombosis and long-term occlusion. It truly achieves a precise match between material properties and the clinical application needs of small-diameter artificial blood vessels.

[0025] 4) To address the tendency of PBT to agglomerate in hexafluoroisopropanol, the preparation sequence of the spinning solution was innovatively adjusted. PBT was dissolved first, followed by the addition of PET and PCL. This fundamentally avoids the problem of uneven component distribution caused by PBT agglomerates, ensuring the uniformity of the ternary spinning solution. At the same time, considering the characteristics of the ternary system, the concentration and molecular weight range of each component were precisely defined, and key process parameters such as the air section and coagulation bath concentration were optimized. This effectively solved the industry problem of difficult spinning of ternary blend systems. The resulting composite fibers have a regular circular cross-section, uniform wall thickness, and no eccentricity or structural defects. The fiber forming quality and stability are greatly improved, making them suitable for industrial mass production. Attached Figure Description

[0026] Figure 1 The images are scanning electron microscope (SEM) images of the spreading behavior of the outer shell liquid on the core liquid in Comparative Examples 1, 2 and 1. In the figure, (a) is Comparative Example 1, (b) is Comparative Example 2 and (c) is Example 1. Figure 2 The images are scanning electron microscope (SEM) images of the spreading behavior of the outer shell liquid on the core liquid in Comparative Examples 1, 2 and 1. In the figure, (a) is Comparative Example 1, (b) is Comparative Example 2 and (c) is Example 1. Figure 3 The cross-section and surface hyper-depth of the hollow fiber prepared in Comparative Example 1, Comparative Example 2 and Example 1 are shown in the figure. (a) and (d) are Comparative Example 1, (b) and (e) are Comparative Example 2, and (c) and (f) are Example 1. Figure 4 The images show scanning electron microscope (SEM) images of the cross-sectional microstructure of hollow fibers obtained in Comparative Examples 1, 2 and 1. In the figures, (a) and (d) are Comparative Example 1, (b) and (e) are Comparative Example 2, and (c) and (f) are Example 1. Figure 5 The porosity test results are for the hollow fibers prepared in Comparative Example 1 (PET), Comparative Example 2 (PET / PCL), and Example 1 (PET / PCL / PBT). Figure 6The figures show the mechanical property test results of the hollow fibers prepared in Comparative Example 1 (PET), Comparative Example 2 (PET / PCL), and Example 1 (PET / PCL / PBT). The figures include: (a) axial tensile stress test results of the hollow fibers; (b) axial elongation at break test results of the hollow fibers; (c) circumferential strain test results of the hollow fibers; (d) radial tensile stress test results of the hollow fibers; and (e) radial elongation at break test results of the hollow fibers. Figure 7 The results of the hemolysis rate test of hollow fibers prepared by Comparative Example 1 (PET), Comparative Example 2 (PET / PCL) and Example 1 (PET / PCL / PBT) are shown in the figure. (a) Centrifuged sample of positive control group, (b) Centrifuged sample of negative control group, (c) Hemolysis rate of hollow fiber. Detailed Implementation

[0027] The present invention will be further described below with reference to the embodiments.

[0028] Unless otherwise specified, all raw materials used in the examples were commercially available.

[0029] PET: Mn=30000; PCL: Mn=50000; PBT: Mn=30000.

[0030] Example 1 The method for preparing the PET / PCL / PBT ternary composite hollow fiber for artificial blood vessel architecture includes the following steps: (1) Place 20 ml of hexafluoroisopropanol on a stirrer, add 2.0 g of PBT powder at a speed of 300 r / min, mix evenly, then add 3.2 g of PET, mix evenly, then add 1.2 g of PCL and mix evenly to obtain a ternary mixed solution as the outer shell liquid. After standing to remove bubbles, the outer shell liquid is obtained. (2) Weigh 5.5g of sodium alginate powder and mix it with 100ml of ultrapure water. Stir mechanically until it is completely dissolved. At this time, the solution is viscous and there are no flocculent substances. After standing to remove bubbles, the inner core liquid is obtained. Mix 700ml of 95% ethanol with 300ml of ultrapure water to obtain a coagulation bath.

[0031] Place the outer shell liquid and inner core liquid into the syringe, connect the coaxial needle (6mm outer diameter, 4mm inner diameter), place it into the spinning equipment, place the coagulation tank containing the coagulation bath under the coaxial needle, lay a layer of 5.2wt.% sodium alginate solution at the bottom of the coagulation tank, and set a 1cm air gap between the needle tip and the coagulation bath. (3) Start the spinning equipment. The flow rate of the outer shell liquid is 2 ml / min and the flow rate of the inner core liquid is 3 ml / min. After the outer shell liquid and the inner core liquid enter the coagulation bath of the coagulation tank through the air section, the nascent fibers are drawn out and placed in the coagulation bath for 120 seconds before being collected. (4) Place the collected fibers in a deionized water bath and let stand for 12 hours. Replace the deionized water every 4 hours to remove the solvent. Then, use a syringe to inject deionized water into the fiber pores 5 times to remove the spinning core liquid, thus obtaining PET / PCL / PBT ternary composite hollow fiber.

[0032] Example 2 The method for preparing the PET / PCL / PBT ternary composite hollow fiber for artificial blood vessel architecture includes the following steps: (1) Place 20 ml of hexafluoroisopropanol on a stirrer, add 1.6 g of PBT powder at a speed of 300 r / min, mix evenly, then add 3.2 g of PET, mix evenly, then add 1.6 g of PCL and mix evenly to obtain a ternary mixed solution as the outer shell liquid. After standing to remove bubbles, the outer shell liquid is obtained. (2) Weigh 5.5g of sodium alginate powder and mix it with 100ml of ultrapure water. Stir mechanically until it is completely dissolved. At this time, the solution is viscous and there are no flocculent substances. After standing to remove bubbles, the inner core liquid is obtained. Mix 600ml of 95% ethanol with 400ml of ultrapure water to obtain a coagulation bath.

[0033] Place the outer shell liquid and inner core liquid into the syringe, connect the coaxial needle (6mm outer diameter, 4mm inner diameter), place it into the spinning equipment, place the coagulation tank containing the coagulation bath under the coaxial needle, lay a layer of 5.2wt.% sodium alginate solution at the bottom of the coagulation tank, and set a 1cm air gap between the needle tip and the coagulation bath. (3) Start the spinning equipment. The flow rate of the outer shell liquid is 2 ml / min and the flow rate of the inner core liquid is 3 ml / min. After the outer shell liquid and the inner core liquid enter the coagulation bath of the coagulation tank through the air section, the nascent fibers are drawn out and placed in the coagulation bath for 120 seconds before being collected. (4) Place the collected fibers in a deionized water bath and let stand for 12 hours. Replace the deionized water every 4 hours to remove the solvent. Then, use a syringe to inject deionized water into the fiber pores 5 times to remove the spinning core liquid, thus obtaining PET / PCL / PBT ternary composite hollow fiber.

[0034] Example 3 The method for preparing the PET / PCL / PBT ternary composite hollow fiber for artificial blood vessel architecture includes the following steps: (1) Place 20 ml of hexafluoroisopropanol on a stirrer, add 0.8 g of PBT powder at a speed of 300 r / min, mix evenly, then add 3.2 g of PET, mix evenly, then add 1.6 g of PCL and mix evenly to obtain a ternary mixed solution as the outer shell liquid. After standing to remove bubbles, the outer shell liquid is obtained. (2) Weigh 5.5g of sodium alginate powder and mix it with 100ml of ultrapure water. Stir mechanically until it is completely dissolved. At this time, the solution is viscous and there are no flocculent substances. After standing to remove bubbles, the inner core liquid is obtained. Mix 600ml of 95% ethanol with 400ml of ultrapure water to obtain a coagulation bath.

[0035] Place the outer shell liquid and inner core liquid into the syringe, connect the coaxial needle (6mm outer diameter, 4mm inner diameter), place it into the spinning equipment, place the coagulation tank containing the coagulation bath under the coaxial needle, lay a layer of 5.2wt.% sodium alginate solution at the bottom of the coagulation tank, and set a 1cm air gap between the needle tip and the coagulation bath. (3) Start the spinning equipment. The flow rate of the outer shell liquid is 2 ml / min and the flow rate of the inner core liquid is 3 ml / min. After the outer shell liquid and the inner core liquid enter the coagulation bath of the coagulation tank through the air section, the nascent fibers are drawn out and placed in the coagulation bath for 120 seconds before being collected. (4) Place the collected fibers in a deionized water bath and let stand for 12 hours. Replace the deionized water every 4 hours to remove the solvent. Then, use a syringe to inject deionized water into the fiber pores 5 times to remove the spinning core liquid, thus obtaining PET / PCL / PBT ternary composite hollow fiber.

[0036] Comparative Example 1 The method for preparing PET hollow fibers includes the following steps: Measure 20ml of HFIP into a beaker, seal with plastic wrap, and place on a magnetic stirrer.

[0037] Weigh 5.4g of PET powder and mix it with HFIP until homogeneous. Let it stand to remove bubbles, then inject it into a syringe (20ml size) to obtain the outer shell liquid.

[0038] Weigh 5.5g of sodium alginate powder, mix it with 100ml of deionized water and stir well. Let it stand to remove bubbles, then inject it into a syringe (20ml size) to obtain the inner core fluid.

[0039] Mix 600ml of alcohol with 400ml of deionized water until homogeneous to obtain a coagulation bath.

[0040] Use a syringe to spread the sodium alginate solution to the bottom of the coagulation tank to prevent the fibers from sticking to the bottom and breaking. Let it stand until the sodium alginate solution spreads out before pouring it into the coagulation bath.

[0041] Place the shell liquid and core liquid at the spinning machine's feed pump and connect them to the coaxial needle using a silicone hose.

[0042] Spinning process: Feed speed: Shell liquid flow rate: Core liquid flow rate = 2ml / min: 3ml / min, Air section: 1cm. Nascent fibers are placed in a coagulation bath for 120s, collected, and placed in clean water for 12h. The water is changed every 4h to remove residual solvent.

[0043] Comparative Example 2 The preparation method of PET / PCL binary composite hollow fiber includes the following steps: Same as Comparative Example 1.

[0044] the difference: 1. Dissolve 5.4g of PET and 1.0g of PCL in 20ml of hexafluoroisopropanol to obtain the outer shell liquid; 2. Outer shell fluid flow rate: Inner core fluid flow rate = 2.5 ml / min : 3 ml / min.

[0045] Scanning electron microscope (SEM) images of the spreading behavior of the outer shell fluid on the core fluid in Comparative Examples 1, 2, and 1 are shown below. Figure 1 As shown in the figure, (a) is Comparative Example 1, (b) is Comparative Example 2, and (c) is Example 1.

[0046] Scanning electron microscope (SEM) images of the spreading behavior and surface morphology of the outer shell liquid on the core liquid in Comparative Examples 1, 2, and 1 are shown below. Figure 2 As shown in the figure, (a) is Comparative Example 1, (b) is Comparative Example 2, and (c) is Example 1.

[0047] Depend on Figure 1 and Figure 2 It can be seen that in the PET / PCL / PBT ternary system, due to the greater difference in compatibility between PBT and other components, the degree of phase separation is significantly intensified, ultimately forming a surface structure with larger pore size, more developed pores, and uniform distribution.

[0048] The cross-sections and surface depths of the hollow fibers prepared in Comparative Examples 1, 2, and 1 are as follows: Figure 3 As shown in the figure, (a) and (d) are comparative examples 1, (b) and (e) are comparative examples 2, and (c) and (f) are examples 1.

[0049] Depend on Figure 3It can be seen that the hollow fibers prepared from the three components in Example 1 all have regular circular cross-sections, uniform wall thickness, and no obvious eccentricity or defects. The PET in Comparative Example 1 and the PET / PCL blended fibers in Comparative Example 2 have smooth and flat surfaces. Although the PET / PCL / PBT ternary blended fibers have regular cross-sections, wrinkles distributed along the axial direction appear on the surface, and the wrinkle morphology shows obvious regional differences: the upper wrinkles are thin and dense, while the lower wrinkles are wide and short with larger gaps. This can simulate the extracellular matrix structure of natural blood vessels, significantly promote endothelial cell adhesion and proliferation, solve the problem of low endothelialization efficiency of binary composite fibers, and improve the biocompatibility of artificial blood vessels with the human body.

[0050] Scanning electron microscope (SEM) images of the cross-sectional microstructure of hollow fibers obtained in Comparative Examples 1, 2, and 1 are shown below. Figure 4 As shown in the figure, (a) and (d) are comparative examples 1, (b) and (e) are comparative examples 2, and (c) and (f) are examples 1.

[0051] Depend on Figure 4 It can be seen that the cross-section of the PET / PCL / PBT ternary blend fiber prepared in Example 1 exhibits a more loose macroporous structure, with improved pore size uniformity. The pores are connected by a relatively coarse, thin film-like rolled material, and the inner walls of the pores exhibit a smoother and more continuous state.

[0052] The porosity of the hollow fibers prepared in Comparative Example 1, Comparative Example 2 and Example 1 was tested. Porosity: YY / T0500-2021.

[0053] Porosity: Three pieces of fixed size (1) were cut from the prepared composite hollow fiber. Samples (1 cm) were vacuum dried for 8 hours; the mass of the composite hollow fiber in each sample was measured as the dry weight W. d After weighing each sample by dry weight, it was immersed in butanediol solution until saturated. After saturation, the wet weight W of the fiber was weighed again. w ; Calculate the porosity ε according to formula (1):

[0054] In the formula, ε is the porosity of the hollow fiber, and ρ p ρ represents the density of the hollow fiber (calculated based on the added substances to determine the average fiber density). 丁 The density of butanediol is 1.015-1.018 g / cm³. 3 W w W represents the wet weight of the fiber. d This refers to the dry weight of the fiber.

[0055] The porosity test results of the hollow fibers prepared by Comparative Example 1 (PET), Comparative Example 2 (PET / PCL), and Example 1 (PET / PCL / PBT) are as follows: Figure 5 As shown, the PET / PCL / PBT ternary blend fiber has the highest porosity, reaching over 65%.

[0056] The mechanical property test results of the hollow fibers prepared by Comparative Example 1 (PET), Comparative Example 2 (PET / PCL), and Example 1 (PET / PCL / PBT) are as follows: Figure 6 As shown in the figure: (a) axial tensile stress test results of hollow fiber; (b) axial elongation at break test results of hollow fiber; (c) circumferential strain test results of hollow fiber; (d) radial tensile stress test results of hollow fiber; (e) radial elongation at break test results of hollow fiber. The above mechanical property test standard is ISO 7198:2019.

[0057] Depend on Figure 6 It is known that pure PET forms uneven finger-like pores and loose granular aggregates, resulting in numerous structural defects, significant stress concentration, and the worst overall mechanical properties. In PET / PCL binary blend fibers, PCL, as the dispersed phase, forms a bicontinuous structure and a uniformly connected porous network with PET, achieving a good balance between strength, toughness, and compliance. In PET / PCL / PBT ternary blend fibers, a large-pore structure with uniform pore size is formed, and the improved pore wall regularity maximizes the radial tensile strength.

[0058] The hemolysis rate test results of the hollow fibers prepared by Comparative Example 1 (PET), Comparative Example 2 (PET / PCL), and Example 1 (PET / PCL / PBT) are as follows: Figure 7 As shown in the figure. (a) Centrifuged sample from the positive control group, (b) Centrifuged sample from the negative control group, (c) Hemolysis rate of hollow fibers. The standard for hemolysis rate testing is ISO 10993-4:2017.

[0059] Depend on Figure 7 It can be seen that the hemolysis rate of all three is less than 5%, which meets the requirements of the international standard ISO 10993-4 for blood contact materials and has blood compatibility.

Claims

1. A PET / PCL / PBT ternary composite hollow fiber for artificial blood vessel architecture, characterized in that, Hollow fibers are produced by spinning solution made from a mixed solution of PET, PCL and PBT. The hollow fibers exhibit a multi-level structure in which macroporous networks and micropores coexist. Specifically, the macroporous network is a loose macroporous structure with uniform pore size connected by a thin film-like rolled material. The inner walls of the pores are smooth and continuous, and the fiber surface exhibits a wrinkled topology distributed along the axial direction.

2. A method for preparing the PET / PCL / PBT ternary composite hollow fiber for artificial blood vessel architecture as described in claim 1, characterized in that, Includes the following steps: (1) After mixing PBT with solvent evenly, add PET and PCL and mix evenly to obtain a ternary mixed solution as the outer shell liquid, and let it stand to degas; (2) The outer shell liquid and the inner core liquid are placed into the syringe, connected to the coaxial needle, and placed into the spinning equipment. The coagulation tank containing the coagulation bath is placed below the coaxial needle, and an air section is set between the end of the needle and the coagulation bath. (3) Start the spinning equipment so that the outer shell liquid and the inner core liquid enter the coagulation bath of the coagulation tank through the air section, and then be drawn to obtain nascent fibers. After being placed in the coagulation bath and left to stand, they are collected. (4) Place the collected fibers in a water bath to remove the solvent completely. Then, use a syringe to inject water into the fiber pores to remove the spinning core liquid, thus obtaining PET / PCL / PBT ternary composite hollow fibers.

3. The method for preparing PET / PCL / PBT ternary composite hollow fibers for artificial blood vessel architecture according to claim 2, characterized in that, In step (1), the concentration of PET in the outer shell liquid is 8wt.%-10wt.%, the concentration of PCL is 2wt.%-6wt.%, and the concentration of PBT is selected to be 2wt.%-6wt.%.

4. The method for preparing PET / PCL / PBT ternary composite hollow fibers for artificial blood vessel architecture according to claim 2, characterized in that, The number average molecular weight of PET in step (1) is 20,000-40,000, the number average molecular weight of PCL is 40,000-60,000, and the number average molecular weight of PBT is 20,000-40,000.

5. The method for preparing PET / PCL / PBT ternary composite hollow fibers for artificial blood vessel architecture according to claim 2, characterized in that, The inner core fluid in step (2) is a mixture of sodium alginate and water, with the concentration of sodium alginate in water being 2wt.%-7wt.%.

6. The method for preparing PET / PCL / PBT ternary composite hollow fibers for artificial blood vessel architecture according to claim 2, characterized in that, The coagulation bath in step (2) is a mixture of ethanol and water, with the volume concentration of ethanol in the water being 55-70%.

7. The method for preparing PET / PCL / PBT ternary composite hollow fibers for artificial blood vessel architecture according to claim 2, characterized in that, In step (2), a layer of sodium alginate solution is laid at the bottom of the coagulation tank.

8. The method for preparing PET / PCL / PBT ternary composite hollow fibers for artificial blood vessel architecture according to claim 2, characterized in that, The height of the air section in step (2) is 1-2 cm.

9. The method for preparing PET / PCL / PBT ternary composite hollow fibers for artificial blood vessel architecture according to claim 2, characterized in that, The flow rate of the outer shell liquid in step (3) is 2-3 ml / min, the flow rate of the inner core liquid is 2-3.5 ml / min, and the standing time in the coagulation bath in step (3) is 60-180 s.

10. The method for preparing PET / PCL / PBT ternary composite hollow fibers for artificial blood vessel architecture according to claim 2, characterized in that, In step (4), the water bath is left to stand for 3-15 hours, and water is introduced into the fiber pores to rinse 3-8 times.

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