Ablation of polytetrafluoroethylene using a continuous CO₂laser beam

Abstract

The ablation of polytetrafluoroethylene (PTFE) is studied using a continuous CO2 laser beam of 30–50 W at a mean intensity of 0.05–50 MW m−2. The ablation products and changes in the target layer are examined using infrared spectroscopy, x-ray photoelectron spectroscopy, x-ray diffraction and electron microscopy. The main experiments were conducted with an unfocused beam of intensity 0.9–1.2 MW m−2. The radiation–polymer interaction characteristics were found to change appreciably as the ablation conditions are approached. Within the polymer layer, light scattering diminishes and true resonant light absorption increases. Two distinct polymer components, which differ primarily in their resistance to CO2 laser radiation, were found to exist under ablation conditions. The less stable component depolymerizes intensively, while the more resistant component is blown up into fibres by intense gas flow. The reasons behind this behaviour are discussed. Preliminary gamma irradiation of PTFE is found to have a significant influence on the laser ablation process.

Degradation of γ-irradiated linear perfluoroalkanes at high dosage

“…The radiation Table 1 Experimental EPR hyperfine parameters of the free radicals formed by radiolysis at 77 K of polytetrafluoroethylene and short-chain linear perfluoroalkanes as reported in Refs. [11,12] Radical…”

“…A similar study of polyvinyl fluoride has been carried out [10]. In addition, CO 2 laser ablation of PTFE after g-irradiation led to enhanced fiber formation as compared to polymers that were not irradiated [11].…”

The effect of γ-irradiation on laser ablation of polyketone

“…The result ing polymer plates were deflashed and further used to prepare specimens for irradiation. Ablation experiments were performed in the vac uum system described in [10][11][12][13][14][15]. The radiation entrance window of the chamber was made from NaCl.…”

“…Heating a polymer by laser irradiation significantly alters the molecular topological structure of the poly mer [10][11][12][13][14][15], as determined by thermomechanical spectrometry (TMS) [15,16]. The TMS technique has been successfully used to study the effect of 60 Co γ radiation on the molecular topological structure of POK [17].…”

Fabrication of polystyrene microfluidic devices using a pulsed CO2 laser system

“…A CO 2 laser emits infrared radiation at a wavelength of 10.6 lm, which is not capable of directly breaking the chemical bonds, so that it is a totally photothermal mechanism for the CO 2 laser ablation process (Nayak et al 2008). CO 2 laser systems have been widely used for rapid production of microfluidic systems with polymers such as PMMA (Snakenborg et al 2004;Yuan et al 2007;Huang et al 2010), PDMS Huft et al 2010), PC (Qi et al 2009), and PTFE (Tolstopyatov 2005).…”