Research And Improvement Of Membrane For Septal Defect Occlusion Devices

Septal defect which is a familiar kind of congenital heart disease includes Atrial and Ventrical Septal Defects and Patent Ductus Arteriosus. It can be treated by delivering an occlusion device through a catheter to remote location in a patient's heart. An occlusion device is composed of a bracket and membranes sewed on it. When the occlusion device is released and expand at the specific locations within a patient's heart, the membranes are employed to block off blood and provide shelter for tissue climbing and growing. Performance of membranes is determinate to the success of this transcatheter closure. Thus research and development of new membranes which have better performance is significant to society.Research is developed according to the medicinal standpoint of "seeping occlusion" about the request of occlusion membranes. This paper has two keystones. One is compound process of thin polyester spunbond nonwovens and PTFE film. The other is coating process with polyurethane of thin polyester spunbond nonwovens. The main content of this research as follows:1. Try to compound PTFE film and polyester spunbond nonwovens by supersonic wave, but it is failed. Try to compound PTFE film and polyester spunbond nonwovens by spunlace, but it is failed too. It shows that these two ways aren't fit for compounding PTFE film and polyester spunbond nonwovens.2. Compound PTFE film and polyester spunbond nonwovens by hot rolling without any chemical adhesives and analyze the performances of these composites. When select 240°C hot-rolling temperature, 16MPa hot-rolling pressure and 150s hot-rolling time, the stripping strength of the composite is the highest. Otherwise, the strongest factor is hot-rolling pressure and the weakest factor is hot-rolling time. After compounding, strength of the composite become stronger and pore size become smaller. The terms of hot rolling process won't influence the strength and the pore size of the composite.3. Modify the surface of PTFE film with plasma before compounded. Test and analyze the performances of these composites. The conclusions as follows: plasma treatment can modify the surface of PTFE film a certain extent and increases stripping strength of the composite; The terms of plasma treatment won't influence strength and pore size of the composite. 4. Try to use transfer coating process, dry coating process, wet coating process and dry coating process with salt, but they all can't produce suitable membranes. Finally, find the wet coating process with salt is the best process. Test performances of the composite and analyze how do concentration of coating solution, temperature of setting bath and concentration of setting solution influence the performances. The conclusions as follows: strength of the coating materials increases and pore size diminishes as concentration of coating solution increases; When temperature of setting bath is lower than 70°C, strength of the coating materials increases and pore size larges as temperature of setting bath increases; When temperature of setting bath is higher than 70°C, strength of the coating materials decreases and pore size diminishes as temperature of setting bath increases; Strength of the coating materials is highest when concentration of setting bath is 6% and pore size of the coating materials diminishes as concentration of setting bath increases; The influence of these three factors on water permeability is as same as the influence on pore size.