N2 supercritical jet to modify the characteristics of polymer material surfaces: Influence of the process parameters on the surface topography

Abstract

Foreign body reaction (FBR) is a critical issue to be addressed when polymeric implants are considered in the medical field to treat pathologies involving hernia repair, revascularization strategies in arterial disease, and aneurysm or heart valve replacement. The natural porosity of textile materials tend to induce exaggerated tissue ingrowth which may prevent the implants from remaining flexible. One hypothesized way to limit the FBR process is to increase the material surface roughness. Supercritical N2 jet particle projection is a novel technique to provide enough velocity to particles to induce plastic deformation on the impacted surface. This work investigates the influence of supercritical N2 jet projection parameters like jet static pressure, standoff distance (SoD), particle size and density on the roughness that can be obtained on polyester flat polymer surfaces. Results bring out that particles generate craters on the polymeric impacted surface, with size increases correlated with the jet pressure and the particle diameter. With a pressure of 1,000 bars, 300‐mm SoD, and a particle mass flowrate of 0.6 g/s, it is possible to obtain a uniform 5 μm roughness on the impacted surface. This value is in the range of the 10 μm fiber size which is commonly used in medical textile implants. Basically, result brings out that whatever the particle size or particle flow rate, the SoD has the most significant effect on the roughness. POLYM. ENG. SCI., 59:616–624, 2019. © 2018 Society of Plastics Engineers