Nanoscale Deposition Of Kevlar By Sublimation

摘要

KevlarR is a polymer with outstanding mechanical properties widely used as fibres. Until now, its sublimation has never been investigated in detail. Here we show that it is possible to prepare nanoscale deposits by sublimating Kevlar-29 fibres. The thermal behaviour of the polymer was analysed by thermo-gravimetric analysis and differential scanning calorimetry. The depositions were carried out on the surface of a highly oriented pyrolytic graphite substrate at temperatures between 400 and 450 ℃ under reduced pressure. The characterization of the deposits by infrared and X-ray photoelectron spectroscopy confirmed that they are really made of Kevlar. Their morphology was investigated by AFM. Intermolecular interactions play a fundamental role in the impressive cohesion of Kevlar fibres. However, they can be significantly weakened upon heating. In appropriate experimental conditions, it is possible to sublimate Kevlar without decomposing the polymer chain itself.