| Vascular grafts are special tubes that serve as artificial replacements for damaged blood vessels. They are already commercially available, mainly produced from Polyethylene Terephthalate (PET) knitted or woven fabrics or the expanded polytetrafluoroethylene (ePTFE). The purpose of the vascular graft prostheses or implantation is not only to keep a patient alive, but also for the patient to continue with their normal lives, as a worker. PET and ePTFE have been successfully used in large diameter grafts; however, small caliber grafts still show an unacceptable high percentage of failure, due to surface forces, blood plasma proteins are adsorbed by the graft, resulting in inflammation, infection, thrombus formation and ultimately vessel reclose. Poly (ε-caprolactone)(PCL) is a promising biodegradable polymer with a longer degradation time. The mechanical properties of the pure PCL cannot meet up with the requirement of vascular grafts. In this thesis composite materials of PCL/PET consider as a novel biomedical materials which it may use to prepare vascular graft with less defects, as composite materials form more than layer, to imitation the human blood vessel which composed of three layers. One of these layers to contribute in the increases of mechanical properties (PET), while the others to improve the biological properties (PCL), which leads to decrease the surface forces of PET and improve the mechanical properties of the PCL. The aims of this study are to●Prepare a new prototype small diameter vascular graft from PCL reinforced with PET weft-knitted tube fabric.●Study the influence of the materials parameters and textile structure on the properties.●Investigate the relationship between structure and elastic properties.Generally, PET weft knitting tube fabrics (6mm diameter) were fabricated with different loop density using small single jersey weft knitting machine. Acetic has been used to dissolve PCL (three molecular weight were used) under stirring at room temperature until a homogeneous solution was formed. PCL solution was composited outside and inside of the weft-knitting fabric with a PTFE rod, and the pure PCL tube was taken as a control. The samples were dried by freeze drying method.The samples have been characterized by using:scanning electron microscopy to determent the porosity structure, textiles universal strength tester has been used to determent the tensile strength and the suture retention strength. The water permeability device has been used to determent the water permeability through the wall graft, filament mightiness instrument to test the elastic recovery and the dynamic-simulated system to determent the compliance.The new prototype vascular grafts have been shown good porosity. And the tensile properties, elastic recovery and the suture retention strength of the new vascular grafts were improved compared with pure PCL vascular graft. However, a significant difference in compliance has shown between the samples, which was produced and the healthy host arteries. On the other hand, with the increase the molecular weight of the PCL, the pore size and the elastic recovery have been improved. Also when increase the loop density of the fabric, the elastic recovery and the suture retention strength have shown improvement.The new composite prototype vascular grafts are promising and they have good potential applications in clinic, due to the good mechanical and biological properties... |
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