小径微孔聚氨酯人工血管的制备条件对微观结构与性能的影响

EFFECT OF PREPARATION CONDITIONS FOR SMALL DIAMETER ARTIFICIAL POLYURETHANE VASCULAR GRAFT ON MICROSTRUCTURE AND MECHANICAL PROPERTIES

目的 研究小径微孔聚氨酯 (polyurethane,PU)人工血管的制备条件对微观结构和力学性能的影响。 方法 采用浸渍 -沥滤法制备 PU小径微孔人工血管 ,通过改变模径、PU材料、盐粒大小、盐胶比和浸渍次数等制备条件 ,控制人工血管的尺寸参数和微观结构 ,测定 PU血管的力学性能 ,观察血管尺寸参数和微观结构对其性能的影响。 结果 PU小径血管内径 2～ 4 mm,壁厚 0 .6～ 1.2 mm,密度 0 .2 3～ 0 .4 9g/ cm3,孔径 4 2～ 95μm,孔隙率5 6 %～ 80 %。血管的径向顺应性 1.2 %～ 7.4 %· 13.3k Pa- 1 ,水渗透性 0 .2 9～ 12 .4 4 g/ (cm2 · min) ,轴向抗张强度1.5 5～ 4 .36 MPa,爆破强度 6 0～ 30 0 k Pa,缝线撕裂强度 19.5～ 96 .2 N/ cm2 。相同尺寸时 ,Chro- noflex制备的小径血管的顺应性和水渗透性优于 PCU- 15 0 0制备的小径血管 ,而 PCU- 15 0 0小径血管的轴向抗张强度、爆破强度和缝线撕裂强度优于 Chro- noflex小径血管。 结论 通过选择材料和优化制备条件 ,可制得具有合适孔径和孔隙率 ,顺应性和其它性能与天然血管匹配的 PU小径血管。

Objective To study the effect of preparation conditions for small diameter polyurethane(PU) vascular graft on microstructure and mechanical properties. Methods The small diameter microporous PU artificial vascular grafts were prepared by dipping and leaching method. The dimension and microstructure were controlled by changing mold diameter, PU materials, salt sizes, salt to polymer ratio, times of dipping layers etc. The mechanical properties of PU grafts including radical compliance, water permeability, longitudinal strength, burst strength, and suture tearing strength were measured and the effect of the graft dimension and microstructure on their properties were studied. Results The internal diameter of grafts prepared was 2 4 mm depending on mold diameter. The wall thickness was 0.6 1.2 mm after dipping 4 8 layers. The density was 0.23 0.49 g/cm 3. The pore was 42 95 μm in diameter. The porosity was 56% 80%. The radical compliance was 1.2% 7.4%·13 3 kPa -1 and higher compliances could be obtained by using more elastic polyurethane, higher salt to polymer ratio, longer diameter and less wall thickness. The water permeability, mainly depending on salt to polymer ratio, diameter, and wall thickness, was 0.29 12.44 g/(cm 2 ·min). The longitudinal strength was 1.55 4.36 MPa correlating with tensile strength of polyurethane and salt to polymer ratio. The burst strength was 60 300 kPa also depending on tensile strength of polyurethane and salt to polymer ratio. The suture tearing strength was 19.5 96.2 N/cm 2 depending on tensile strength of polyurethane but not on the angle of tearing and graft axial directions. The compliance and water permeability of Chronoflex grafts were higher than those of PCU 1500 grafts, but longitudinal strength, burst strength, and suture tearing strength of PCU 1500 grafts were better than those of Chronoflex grafts. Conclusion Small diameter grafts with proper pore sizes, porosity, matching compliance can be obtained by selecting PU materials and optimizing the preparation conditions.