HIGH-POWER LASER-BEAM AND POLYMERIC MATERIAL INTERACTION

Infra-red Laser beam treatment of a semi-crystalline polymer leads to physical transformations of the material. The case of a PET film is considered. In the first part, a numerical method for the calculation of temperature distribution versus time and space in a material exposed to a high power laser beam is presented. It is shown that among parameters intrinsic to the material or related to the Laser beam, absorbance coefficient, power density and interaction time take the greatest part in raising temperature gradient within the sample. In the case of semi-crystalline polymer, the proposed method is shown to induce surface amorphisation under high power density and short interaction time conditions. In the second part, various techniques for the measurement of this amorphous layer thickness are presented and it is shown that theoretical calculations and experimental results are in good agreement.