Mkii golden gate accessory

A Nicolet Nexus 670 spectrometer (Madison, WI, USA) provided with a MKII Golden Gate accessory (Specac) with a diamond crystal at a nominal incidence angle of 45° and ZnSe lens was used to characterized the functional groups of PU0 and TiO₂-PU0 nanocomposite films by Fourier transform infrared spectroscopy (FTIR). The range was between 4000 and 650 cm⁻¹, with a resolution of 8 cm⁻¹ and averaging 32 scans.

Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy was used to identify the characteristic functional groups of SPI films. Measurements were performed with a Nicolet Nexus FTIR spectrometer (ThermoFisher, Madrid, Spain) equipped with an MKII Golden Gate accessory (Specac) with a diamond crystal as ATR element at a nominal incidence angle of 45° with a ZnSe lens. Measurements were recorded in the 4000–750 cm⁻¹ region, using 32 scans at a resolution of 4 cm⁻¹. All spectra were smoothed using the Savitzky–Golay function. Second-derivative spectra of the amide region were used at peak position guides for the curve fitting procedure, using OriginPro 2019b software.

The chemical structure of the unmodified and modified starch and dextrin as well as of the IPDI monomer was analyzed with FTIR (Nicolet-Nexus, Waltham, MA, USA) provided with a MKII Golden Gate accessory (Specac, Orpington, UK) with a diamond crystal at a nominal incidence angle of 45° and ZnSe lens. Spectra were recorded in attenuated reflection (ATR) mode and the evaluation was performed between 4000 and 400 cm⁻¹ at room temperature, averaging 64 scans with resolution of 4 cm⁻¹. The samples were dried at 50 °C for 24 h prior to the analysis.