Use of an Innovative Methodology for the Characterization of Polymers in the Analysis of the UV-Light Radiation Effects

The mechanical behaviour of viscoelastic materials is typically investigated by means Dynamic Mechanical Analysis (DMA) carried out on standardized specimens suitable for laboratory conditions, which can be specifically produced for the test or extracted from a component, causing its destruction. Here, an innovative methodology, based on the instrumented indentation, is presented to assess the mechanical response of polymers’ compound. The innovative device, called VESevo, provides a non-destructive and non-invasive testing procedure allowing the characterization of a material directly in-situ, without the destruction of a component to create a suitable sample. Taking advantage of this methodology, the aim of this work is the study of polymers’ compound viscoelastic properties variations, caused by exposure to UV-rays. The analysis has been carried out on a polymers’ compound designed to be used as a tire tread. UV radiations are usually employed to change properties of the polymers, but there are very few examples of UV-curing effects applied to tires compound as well as the monitoring of properties over time using non-destructive techniques. In order to assess the compound viscoelastic properties variation, a proper test bench has been set, adopting in a combined manner an UV-Lamp and the innovative device VESevo. After that, a dedicated test campaign has been carried out on a tire compound specimens tested in different conditions. The preliminary results highlighted: the ability of the proposed technique to measure the variation in the mechanical behavior of the material induced by exposure to UV rays; significant variations in viscoelastic properties induced on the compound as a function of the time of exposure to UV rays.