In situ polymerization of six-membered cyclic 1,3-dioxane leads to a polymer electrolyte with superior oxidation stability and elevated Li-metal compatibility, which enables the stable operation of Li-metal batteries with various state-of-the-art high-voltage cathodes.

Kraft lignin (KL) was thermally treated at 500 to 1000 °C in an inert atmosphere. Carbon nanostructure parameters of thermally treated KL in terms of amorphous carbon fraction, aromaticity, and carbon nanocrystallites lateral size (L_a), thickness (L_c), and interlayer space (d₀₀₂) were analyzed quantitatively using X-ray diffraction, Raman spectroscopy, and high-resolution transmission electron microscopy. Experimental results indicated that increasing temperature reduced amorphous carbon but increased aromaticity in thermally treated KL materials. The L_c value of thermally treated KL materials averaged 0.85 nm and did not change with temperature. The d₀₀₂ value decreased from 3.56 Å at 500 °C to 3.49 Å at 1000 °C. The L_a value increased from 0.7 to 1.4 nm as temperature increased from 500 to 1000 °C. A nanostructure model was proposed to describe thermally treated KL under 1000 °C. The thermal stability of heat treated KL increased with temperature rising from 500 to 800 °C.

In this study, traditional polyol was partially replaced with green, environmentally friendly cellulose nanofibrils (CNF). The effects of CNF on the performance of CNF-reinforced polyurethane foam nanocomposites were investigated using scanning electron microscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and a compression test. The results showed that the introduction of CNF into the polyurethane matrix not only created stronger urethane bonding between the hydroxyl groups in the cellulose chain and isocyanate groups in polymethylene polyphenylisocyanate, but also developed an additional filler–matrix interaction between CNF and polyurethane. With the increase of the CNF replacement ratio, a higher glass transition temperature was obtained, and a higher amount of char residue was generated. In addition, an increase of up to 18-fold in compressive strength was achieved for CNF-PUF (polyurethane foam) nanocomposites with a 40% CNF replacement ratio. CNF has proved to be a promising substitute for traditional polyols in the preparation of polyurethane foams. This study provides an interesting method to synthesize highly green bio-oriented polyurethane foams.

Lignin graphene oxide was oxidized after Kraft lignin was graphitized by thermal catalytic conversion. The reduced lignin graphene oxide was derived from lignin graphene oxide through thermal reduction treatment. These Kraft lignin, lignin graphite, lignin graphene oxide, and reduced lignin graphene oxide were characterized by scanning electron microscopy, raman microscopy, high-resolution transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, atomic force microscopy and thermogravimetric analysis. The results showed lignin graphite converted from Kraft lignin had fewer layers with smaller lateral size than natural graphite. Moreover, lignin graphene oxide was successfully produced from lignin graphite by an oxidation reaction with an hour-long reaction time, which has remarkably shorter reaction time than that of graphene oxide made from natural graphite. Meanwhile, this lignin-derived graphene oxide had the same XRD, FTIR and Raman peaks as graphene oxide oxidized from natural graphite. The SEM, TEM, and AFM images showed that this lignin graphene oxide with 1–3 average layers has a smaller lateral size than that of graphene oxide made from natural graphite. Moreover, the lignin graphene oxide can be reduced to reduced lignin graphene oxide to fabricate graphene-based aerogel, wire, and film for some potential applications.

Multilayer graphene-encapsulated iron nanoparticles in carbon frames were prepared through catalytic graphitization of kraft lignin as carbon sources using irons as the catalyst at the temperature of 1000°C under argon atmosphere. The effects of different iron loadings on the formation of multilayer graphene-encapsulated iron nanoparticles were investigated using thermogravimetric analysis and temperature-programmed decomposition. The evolution of gaseous products (H₂, CH₄, CO, and CO₂) was measured using an online mass spectroscopy during the catalytic thermal decomposition of kraft lignin. Solid products were measured and characterized by elemental analysis, nitrogen adsorption, X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and Raman spectroscopy. Thermogravimetric analysis curves indicated that peak temperatures of lignin decomposition and carbonization shifted to lower temperatures with an increase of iron/lignin mass ratio. Experimental results showed that the lignin graphitization degree and conversion level to graphene materials increased significantly with the increase of iron/lignin mass ratio.