Effect of Woven Structure and Ratios of Warp and Weft Density on Water Permeability and Thickness of Woven Polyimide Vascular Grafts

Textile vascular grafts are often used to treat the cardiovascular diseases.Scholars continue to search for new materials for the development of vascular grafts with excellent properties,polyimide(PI)fiber is a material suitable for making vascular grafts with high strength,radiation resistance and stable property,as well as non-cytotoxic and satisfying blood compatibility.This study investigated the tensile strength and hydrolytic degradation properties of PI,polyester(PET)and nylon(PA).The results suggested that the PI is suitable for preparing vascular grafts.And influences of different weaves and ratios of warp and weft density on the water permeability,thickness and porosity of PI vascular grafts were analyzed.Vascular grafts with six weaves and two ratios of warp and weft density were designed and prepared.The surface morphology,permeability and thickness were characterized to optimize the structure of the vascular grafts.The results showed that the wall thickness of all the samples is less than 100μm except for the sample with the ratio 2∶3 and 1/3 twill pattern.Permeability is mainly determined by the weave and the ratio of warp and weft density.The samples in plain weave have the lowest water permeability compared with other samples.