Nicolet 8700

The FT-IR spectra were measured using the FT-IR spectrometer (Nicolet 8700; Thermo Electron Corp., Waltham, MA, USA) equipped with the GoldenGate (Specac Corp., Orpington, UK) ATR accessory with a single reflection diamond crystal. The temperature of the crystal was maintained at 25.0 ± 0.1 °C by using an automatic temperature controller (Specac Corp, Orpington, UK) coupled with the ATR accessory. In each measurement, 64 scans were collected with a resolution of 4 cm⁻¹ and the range of 4000–550 cm⁻¹. The spectrum of the filament was measured and later subtracted from every measured spectrum as the background. After measuring all FT-IR spectra corresponding to a selected strain and background subtraction, the average spectrum was calculated. The spectrometer was purged with dry nitrogen to diminish the negative influence of water vapor. Spectragryph V1.2.10 software (Oberstdorf, Germany) was used to process the obtained spectra.

PE polymeric structural change after biodegradation under a high methane dose was recorded by Fourier-transform infrared spectroscopy coupled with attenuated total reflectance (FTIR–ATR; Nicolet 8700, Thermo Electron Co., Waltham, MA, USA) with a scanning power with a resolution of 4 cm⁻¹ and a 500–4000 cm⁻¹ range. PE samples from all treatments including the control (non-inoculated sample) were subjected to FTIR analysis.
PE biodegradation was further confirmed through gel permeation chromatography (GPC) by evaluating the molecular weight changes. A PL-GPC PL50 (Agilent, Santa Clara, CA, USA) system coupled with the triple mixed-b columns and an RI detector was used for this purpose.
PE was solubilized in 1,2,4-tricholobenzene (TCB) and 0.15 butylated hydroxytoluene (BHT) at 160 °C and the same chemicals were used as eluents in GPC. The eluent flow rate was maintained at 1 mL min⁻¹ with a column temperature of 160 °C. Agilent chemstation software A.10.02 (Agilent, Santa Clara, CA, USA) was used for data analysis and Agilent (Agilent, USA) polystyrene standards were used for calibration curves.

The FT-IR spectra were measured using a spectrometer (Nicolet 8700; Thermo Electron Corp., Waltham, MA, USA) equipped with the GoldenGate (Specac Corp., Oprington, UK) ATR accessory with a single reflection diamond crystal. The temperature of the crystal was maintained at 25.0 ± 0.1 °C by using an automatic temperature controller (Specac Corp., Orpington, GB) coupled with the ATR accessory. In each measurement, 64 scans were collected with a resolution of 4 cm⁻¹ and the range of 4000 to 550 cm⁻¹. The spectrum of the filament was measured and later subtracted from every measured spectrum as the background. After measuring all FT-IR spectra corresponding to a selected strain and background subtraction, the average spectrum was calculated. The spectrometer was purged with dry nitrogen to diminish the negative influence of water vapor. Spectragryph V. 1.2.10 software (Oberstdorf, Germany) was used to process the obtained spectra.

Fourier-transform infrared (FTIR) spectroscopy was used to determine the interaction in structures between modified and unmodified AX films [45 (link)]. The testing condition was at 4 Reciprocal Centimeter (cm⁻¹) resolution and 10 Aperture, with the range of the wavenumber between 4000 and 700 cm⁻¹ (Thermo Scientific, Nicolet 8700, Wilmington, DE, USA).