Invenio ftir

Infrared spectra were obtained with a Fourier Transform Infrared Spectrometer (Invenio FTIR, Bruker, Billerica, MA, USA) using a diamond crystal. The spectra were recorded in the range of 500–4000 cm⁻¹, and a resolution of 4 cm⁻¹.

Mechanical testing is conducted according to DIN EN ISO 527-2:2012, applying a strain rate of 25 mm min⁻¹, using an Instron universal testing system (Illinois Tool Works, Glenview, IL, USA) in combination with optical strain measurement. Complementary morphological characterizations include the preparation of polarization micrographs of prepared specimens using a Zeiss AxioImager 2 (Carl Zeiss Microscopy Deutschland GmbH, Jena, Germany) and complementary scanning electron microscopy (SEM) of fractured tensile specimens, applying an SEM of type Zeiss Gemini (Carl Zeiss Microscopy Deutschland GmbH, Jena, Germany). Furthermore, thermal DSC characterizations of manufactured specimens are conducted by applying a constant heating and cooling rate of dT/dt = 10 K min⁻¹. Complementary infrared spectroscopic measurements are based on samples extracted from the center of distinct tensile specimens, allowing for determining the presence of molecular structures characteristic of in situ post-condensation reactions. ATR infrared spectroscopy is conducted using an FT-IR device of the type Invenio FT-IR (Bruker Corporation, Billerica, MA, USA) applying a wavelength resolution of 0.5 cm⁻¹.