Tensor 27 infrared spectrometer

The molecular weight (Mw) of pF1-20 was determined by HPGPC using an Agilent Technologies 1260 series (Agilent Technologies, Santa Clara, CA, USA) apparatus equipped with a Shodex OH-pak SB-804 HQ column (8 mm × 300 mm) and differential refractive index (RI) detector. Chromatographic conditions were performed as the previous method [18 (link),28 (link)]. The Mw was calculated by GPC software (Version 3.4) using a curve fitted by a serials of FG samples with known Mw (52.77, 39.9, 27.76, 14.92, 8.24, 5.30, 3.12 kDa).
The sulfate ester content of pF1-20 was measured by a conductimetric method [23 (link)]. The pFs (4 mg) was dissolved in 2.0 mL of distilled water. The solution was passed through a column (10 × 200 mm) of Dowex® 50WX8 cation exchange resin (H⁺ form), and the acid form of these samples was eluted with water and then the solution was titrated with 2 mM NaOH at room temperature, monitored by a conductivity meter (DDSJ-308A). The sulfate ester content was calculated from the conductivity titration curves.
The FI-IR spectra (KBr pellets) of SvFG and pF1–12 (~1 mg) were recorded on a Bruker Tensor 27 infrared spectrometer (Ettlingen, Germany) in the range of 400–4000 cm⁻¹.

TER was a gift from Professor Sidong Li's laboratory. His group isolated TER from TTO, the essential oil extracted from Melaleuca alternifolia. The protocol of FTIR analysis was conducted as described by Linshi and modifications (21 (link)). Briefly, samples were dissolved in heavy water (D₂O) and detected with a Bruker Tensor 27 infrared spectrometer (Shanghai, China) with a resolution of 4.0 cm⁻¹ and a scan range of 400–4,000 cm⁻¹. An average of 64 scans was required to obtain information about the structure.

Both decomposition and evolved gases were investigated under pyrolytic and thermo-oxidative conditions via Fourier transform infrared (FTIR) spectroscopy coupled with thermogravimetric analysis. For epoxy resins with and without FRs, 10 mg of powder attained from cryomilling were used for measurements, while 5 mg samples were measured for pure FRs. Using a TG 209 F1 Iris (Netzsch Instruments, Selb, Germany), samples were heated at a rate of 10 K min⁻¹ from 30 to 900 °C under a nitrogen or synthetic air (80:20) gas flow of 30 mL min⁻¹. The evolved gases were analyzed using a Tensor27 infrared spectrometer (Bruker Optics, Ettlingen, Germany), which was coupled to the TGA via a transfer line heated to 270 °C.

The short-range ordered structure of the sample was evaluated based on the method of Wang et al. [20 (link)]; 1 mg of sample and 100 mg of KBr were mixed and ground in an agate mortar and pressed into a thin disc. The disc was placed in a TENSOR 27 infrared spectrometer (Bruker, Germany). The IR spectrum in the range of 4000–400 cm⁻¹ was obtained after scanning 32 times with KBr as the background. The IR spectrum was convoluted by OMNIC software (v.9.2; Thermo Scientific, Madison, WI, USA). The spectrum (1200–800 cm⁻¹) was selected with an enhancement factor of 1.9 and a half-peak width of 19 cm⁻¹. Peakfit 4.12 was used for peak separation. Then, the intensity ratio of the peaks at 1047 cm⁻¹ and 1045 cm⁻¹ was calculated.

Fourier transform infrared spectroscopy (FT-IR) was performed to investigate the shifting in the absorbance owing to the chemical binding as immobilization Tm-β-Glu-Tt-ChBD on Ch-MNPs. Among that, the sample was recorded employing a Tensor 27 infrared spectrometer (Bruker, Germany) from KBr disc in the range of 4000–400 cm⁻¹. The morphology of the immobilized Tm-β-Glu-Tt-ChBD particles was investigated using transmission electron microscopy (TEM) (Hitachi H-7650, Japan). The sample was firstly re-dispersed in ethanol via ultrasonic, and then 10 μL was carefully dropped over the copper grid and kept for 30 min to dry totally.