Characterization of talc samples

In order to record infrared (IR) spectra, 1% of sample was pelletized in KBr and then analyzed by a Bruker Tensor 27 FT-IR spectrophotometer. All the spectra were collected in transmission mode in the 4000–370 cm⁻¹ energy range with a 4 cm⁻¹ resolution from 100 scans. A pure KBr pellet was used for the reference.

Thermogravimetric Analysis (TGA) experiments were performed with a Mettler-Toledo TGA/DSC 1 analyzer. An alumina crucible of 70 µL containing approximately 20 mg of sample was heated at a heat flow of 10 °C.min⁻¹ under a dinitrogen flux of 50 mL min⁻¹ in order to reach a final temperature of 900 °C and then brought back to room temperature. Data were analyzed using the STAR^e software.

Powder X-ray patterns were recorded on a Bruker D8 Advance diffractometer equipped with a grazing parabolic Göbel mirror and a Cu emitter (λ_CuKα = 1.541 Å, 40 kV/40 mA). The diffracted beam was collected by a position sensitive Vantek detector.