[20p-B301-1~13] 7.1 X-ray technologies

▼ [20p-B301-8] The laser ablation of polymers studied by pink-beam 4D X-ray phase CT

〇(P)Karol Vegso¹, Masato Hoshino¹, Yanlin Wu², Hidekazu Takano², Atsushi Momose^1,2 (1.JASRI, 2.Tohoku Univ.)

Keywords:4D X-ray phase CT, laser ablation, polymer

The 4D X-ray phase tomography based on X-ray Talbot interferometer (XTI) was used to perform three-dimensional dynamical study of the interaction between infrared laser radiation (λ=1064 nm) and various polymer samples. XTI measures deflection of X-rays at the object and generates phase contrast for soft-matter samples such as polymers and biological samples. The polymers studied by 4D X-ray phase CT were polypropylene (PP), poly(methyl methacrylate) (PMMA) and polycarbonate (PC) that are widely used in industry. The achieved temporal resolution for PP and PMMA was 2 s while for PC was 1 s. The laser was operating in CW mode (P=50 W) during 4D X-ray CT measurement of PP. In the case of PP, the strong melting was dominated followed by extrusion of PP above the top sample surface (Fig. 1). The different morphological changes in PP were successfully recorded by 4D X-ray phase CT. The different scenario was revealed in the case of PMMA for laser operating both in CW mode (50 W) and pulse mode (Δt = 50 ns, f = 154 kHz). While the melting was dominated in the CW mode, the numerous crack formation was observed propagating from the entrance sample surface in the pulse mode. The observations suggest that pulse mode is more suitable for drilling, cutting and trimming of PMMA. The infrared laser radiation induced combustion process on the surface of PC sample. The 4D X-ray phase CT was sensitive enough to observe stream of carbon ash formation on the sample surface. The achieved results establish 4D X-ray phase CT as robust method to study laser ablation of various industry-relevant polymers.