Avance neo 600

The chemical structure analyses of the synthesized PABS and cellulose samples were conducted with an FT-IR spectrophotometer (PerkinElmer Frontier, United States) equipped with an attenuated total reflectance accessory. The spectra were recorded in the wavenumber range of 500–4,000 cm^–1 at a resolution of 4.0 cm^–1 (An et al., 2020b (link)).
¹H nuclear magnetic resonance (¹H NMR) and gel permeation chromatography (GPC) analyses were performed for a more detailed chemical structure analysis of PABS. ¹H NMR was measured using a 600-MHz Fourier transform nuclear magnetic resonance (FT-NMR) (Bruker Avance Neo 600, Germany). PABS (10 mg) was directly dissolved in 0.5 ml D₂O (99.96%, Sigma-Aldrich) to record the ¹H NMR spectrum. The molecular weight was analyzed by GPC (Shimadzu 20A, Japan) equipped with PLgel columns (PLgel 5 μm mixed-C and mixed-D and PLgel 3 μm mixed-E). PABS was dissolved in DMF containing 0.1% LiBr to determine its molecular weight (Youe et al., 2018 (link)).
The contents of different elements (C, H, N, and S) of the synthesized PABS and cellulose samples were determined using an elemental analyzer (Eurovector EA3000, Italy) with a thermal conductivity detector. The surface element analysis of cellulose samples was measured by XPS (Thermo Scientific, United Kingdom) (An et al., 2020a (link)).

Unless otherwise noted, all chemicals were obtained from commercial vendors and used directly without further purification. Analytical reagent (AR) grade solvents were used for all reactions. Reaction progress was monitored by TLC on pre-coated silica plates (Huanghai HSGF254, 0.20 mm, pH 6.2–6.8) and spots were visualised by UV (254 nm). Flash column chromatography was done using silica gel (Qingdao Ocean Chemical Company, 200–300 mesh). ¹H NMR and ¹³C NMR spectra were recorded on a Bruker AVANCE neo 600. High resolution ESI-MS were recorded on Orbitrap Exploris 240 (Thermo Fisher Science, MA, USA).

Fourier transform infrared spectra (FT-IR) were obtained using a Niolet iN10 instrument with an ATR attachment, operating over 400–4000 cm⁻¹ at ambient temperature. The nuclear magnetic resonance (NMR) measurements were carried out on an Avance NEO 600 (Bruker) at 500.13 MHz (¹H). The spectra were referenced to the solvent signal (CDCl₃: δ (¹H) = 7.26 ppm). Thermogravimetric analysis (TGA) data were recorded on a Mettler tga 2 instrument over the range of 25 to 800 °C, with a heating rate of 5 °C min⁻¹ under a flow of N₂ (20 mL min⁻¹). SEM and EDX were acquired on a Schottky Field Emission Scanning Electron Microscope ZEISS MERLIN Compact operating in variable pressure mode with an accelerating voltage of 15 keV.