The Design, Manufacturing And Performance Analysis Of Ultrathin Textile Membrane Used For Stent-Graft

With the improvement of people's health requirements and the changes of medical model, the general trend of surgical treatment has been beginning to towards the simple and direct, mini-traumatic direction. In recent years, for arteriosclerosis, thrombosis embolism, aneurysm and other arterial vasodilatation disease, minimally invasive surgery named endovascular has been developed. In this method, a metal stent-graft complex was transplanted into diseased vascular, which will isolate pathological vasculature from normal blood circulation. Thus the technique is nominated as endovascular graft exclution (EVE). The therapy with the advantages of minimal wound, small amount of bleeding, quick recovery and less complication, has completely resolved the disadvantages of the previous laparoscopy like big wound, complicated operation, high complication rate and mortality, and basically replaced the original open surgery.As a key component of endovascular prosthesis, the tubular textile fabric plays a vital role in isolating the pathological vascular from the normal blood circulation. Therefore, as an artificial blood vessel for endovascular surgery, besides the performance of general artificial blood vessel, it should also have thinner thickness and smaller permeability and so on. However, the ultra-thin fabric specimen developed currently can not fully satisfy the majority of Chinese people's physical characteristic requirements in thickness and permeability, etc. To solve this problem, this thesis has mainly done the following research.Firstly, the raw materials for yarns, the fabric weave and fabric densities, etc, were selected and designed respectively with the design principles of ultra-thin fabric and the performance requirements of the ultra-thin fabric used in endovascular also taken into account. And the 20D/12f and 30D/12f polyester multifilament yarn were selected as the warp yarns.Secondly, to improve the weaving ability of the fine denier polyester multifilament yarns, warp sizing is needed.The PMA and PVA1788 were selected as size according to the ratio of 3:1.Then the fine denier polyester multifilament yarns were sized by using the "double-dipping and dual-pressurization "and " the former-heavy and the latter-light" sizing process, with the size liquor concentration at about 18% ~ 20%.The test weaving shows that warp sizing can improve the weaving ability of the fine denier polyester multifilament yarns remarkably. After sizing, a series of different specifications of whole multifilament yarn fabrics and single-multifilament fabric samples were successfully woven on the reformed full-automatic sample weaving loom in lab, through designing of the weaving parameters and adjusting the weaving process.The thickness, permeability rate and other performance figures of the specimen after desizing were tested and analyzed respectively. The testing shows that the thickness of the samples after desizing was larger than 0.06mm and the permeability rate was lager than 300ml/cm~2/min.Subsequently, in order to reduce the thickness and permeability rate of the woven samples after desizing, a calendaring finishing was given to the specimen by choosing the reasonable calendaring process parameters. The property testing of the samples before and after finishing shows that calendaring finishing can lower the thickness and water permeability rate of the samples significantly. Moreover, the thickness of some samples was less than 0.06mm, and thepermeability rate was less than 300ml/cm~2 /min, and especially some samples are even impervious after calendaring finish, achieving the goals set in the issue.And then, the tensile fracture property before and after calendaring of the samples with the thickness and permeability meeting the requirements were tested. The test shows that proper calendaring finish has less damage to the fabric tensile breaking strength, and the overall performance of specimen 4 (with the warp yarn 30D/12f, the weft yarn 20D/12f, the warp density 960 per 10cm, the weft density 960 per 10cm, the weave 3/1 twill) is better than other else.Finally, the sample 4 with the performance meeting the requirement was selected to be done animal experiments the Shanghai Sixth People's Hospital. It was found that the samples developed in this subject played an ideal isolation effect, and the fabric membrane material had a high safety reliability and good histocompatibilityIn general, according to the performance requirements of the fabrics used for endovascular exclusion and in reference to the ultra-thin fabric design principles, based on the overall consideration of yarn materials, fabric density, weave and other various factors, a kind of ultra-thin multifilament yarn fabric with the thickness at about 0.06mm and the permeability rate very small were woven and the parameters for sample preparation process was developed by sizing, warping, weaving and calendaring process eventually. And thus this also makes the endovascular surgery applied to more fine blood vessels possible.