Influence of fabrication process on the final properties of natural-rubber latex tubes for vascular prosthesis

Abstract

We report a process of fabrication of latex tubes using the dip-coating technique. We investigated centrifuged latex, with different original viscosities, extracted from the Hevea brasiliensis. The influence of the main deposition parameters (dip-coating velocity, mold material, mold diameter and number of coatings) and post-deposition drying process parameters (temperature and time) on the properties of the final samples are investigated and discussed. Additional investigation about the elastic behavior of the tubes is presented for strain values up to rupture. The rupture occurred at 120 mm for tubes 15 mm-long, which represents an elongation of 800%. The tubes presented two distinct elastic mechanisms, with the most elastic one being observed below an elongation of about 500%. During a cycled strain experiment with strain values below the rupture point, a hysteretic-like curve was observed, which was related to the uncurling and recurling of the polymeric chains.