Chemical and Thermal Characteristics of Ion-Exchanged Lignosulfonate

Abstract

Lignosulfonate features sulfonate groups, which makes it soluble in water and hence, suitable for a wide range of applications. However, its characterization is challenging because of its limited solubility in organic solvents. Thus, this study investigated the chemical and thermal characteristics of ion-exchanged sodium lignosulfonate (Na-LS) and compared it with those of industrial kraft lignin derived from softwood and hardwood. The results demonstrated that the ion exchange successfully converted Na-LS to lignosulfonic acid (H-LS), as proven by the Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and elemental analysis. H-LS has a greater apparent molecular weight than those of Na-LS and softwood and hardwood kraft lignin (SKL and HKL). According to 31P nuclear magnetic resonance (NMR) analysis, H-LS has less phenolic OH than SKL and HKL, indicating that it has more polymeric chains. Furthermore, H-LS has substantially more native side chains, such as β-O-4 units, than SKL and HKL. Thermal analysis revealed that H-LS has a greater glass temperature (Tg) than SKL and HKL, although Na-LS has a lower Tg than SKL and HKL. In addition, H-LS degraded faster than Na-LS did because the acid condition accelerated degradation reaction.

Adhesion of Technical Lignin-Based Non-Isocyanate Polyurethane Adhesives for Wood Bonding

“…In contrast, the carbon and oxygen contents of AI-HKL were significantly different from those of AS-HKL and C-HKL. The ash content of the three lignin samples was substantially lower than that obtained in other pulping processes, and high impurities remained in the order of AI-HKL, C-HKL, and AS-HKL [49,59]. The elemental composition of LS was similar to previous studies [60][61][62][63].…”

“…Next, the peaks detected in the HKL-NIPU or LS-NIPU spectrum are described. The small peak at 1510 cm −1 observed only in the LS-NIPU spectrum is associated with the C-H bending vibration (C=C bond) of -CH 2and -CH 3 of LS [59]. This observation implies that unreacted LS remained after carbonation and polyamination, which affected the adhesion performance.…”

Wood waste-derived dual-mode materials paving the way for year-round energy saving in buildings

“…Lignin possesses strong infrared thermal emission capabilities and exhibits significant molecular vibrations in the mid-infrared range. 48,49 The cooling surface radiate a net heat flux through the atmospheric transparency window (8 to 13 mm) to the cold sink of outer space in the form of infrared radiation. And cooling surface exhibits high emissivity (similarly greater than 0.9) in the infrared range, emitting strongly between 60 degrees, indicating a stable heat flow density release when the relative angle of the cooling surface to the sky is different, which 10% higher than formerly reported values (Fig.…”

Trapping an Ester Hydrate Intermediate in a π-Stacked Macrocycle with Multiple Hydrogen Bonds

“…The existence of S VI was confirmed using the X-ray photoelectron spectroscopy (XPS) study. The observed peaks at 168.15 and 169.25 eV corresponded to S VI 2p 3/2 and S VI 2p 1/2 , respectively [39,40] (Figure 3b). A temperature-dependent magnetization study of compound 1 was also performed under 1 kOe field in the 2-300 K range.…”