Graphitization of Lignin-Phenol-Formaldehyde Resins

Abstract

Environmental friendliness and cost demand the development of lignin-modified phenolic (LPF) resins for application as a binder for carbon-containing refractories (CCRs) production. Moreover, the in-situ graphitization of such resins can produce crystalline carbon, which is an essential component of CCRs. Consequently, this study investigated LPF resins graphitization using ferrocene, boron oxide and boric acid. The modified resins were synthesized using thermally treated kraft lignin based on 1.5 formaldehyde to phenol molar ratio and with up to 30 wt.% lignin as phenol replacement. The resins chemical composition and the structural organization and oxidation resistance of carbons derived from the plain resins and those containing the graphitizing additives were determined. The results showed that ferrocene and the boron compounds could induce graphitic carbon generation when carbonizing LPF resins at 1500 °C for 5 hours. The best graphitization level (73%) was achieved when 10 wt.% boric acid was added to the resin produced with 20 wt.% lignin. Regarding the formulations containing ferrocene, the highest amount of graphitic carbon (48%) was generated when 5 wt.% of this additive was added to the resin synthesized with 10 wt.% lignin. The carbons derived from the formulations containing boron oxide presented the best oxidation resistance.

Properties of High-Density Fiberboard Bonded with Urea–Formaldehyde Resin and Ammonium Lignosulfonate as a Bio-Based Additive

“…Therefore, it is important to identify and develop new approaches and industrial applications of this underutilized raw material. The valorization of lignin as a renewable feedstock for the production of valued-added, bio-based chemicals, including wood adhesives, has gained significant industrial and scientific interest due to its annual renewability and phenolic structure, allowing partial replacement of phenol in phenol–formaldehyde (PF) resins [ 77 , 78 , 79 , 80 , 81 ]. In addition, lignin contains methoxyl, carbonyl, and aliphatic hydroxyl groups that are favorable for modifications, e.g., methylolation and phenolation, aimed at increasing its chemical reactivity to formaldehyde [ 82 ].…”

Optimization of the Hot-Pressing Regime in the Production of Eco-Friendly Fibreboards Bonded with Hydrolysis Lignin

“…The main difficulty in using lignin as a binder in wood-based panels is its introduction, retention and activation [52][53][54]. At present, a solution to this problem is sought mainly by modification of lignin [55,56], including its enzymatic treatment [57]. Lignin contains different functional groups, i.e., methoxyl, hydroxyl, and carbonyl groups, which allow its chemical modification, applied mostly to increase its reactivity.…”

Preparation and application of sunlight absorbing ultra-black carbon aerogel/graphene oxide membrane for solar steam generation systems

“…Also L a and L c were respectively equal to 1.63 nm and 0.79 nm representing the formation of nano sized graphitic structure. 42,43 Porous texture assessment Textural properties of the CA was evaluated with N 2 adsorptiondesorption isotherm. As depicted in Fig.…”

“…k is 1.84 for L a and 0.89 for L c . 42,43 To evaluate the specic surface area and pore size distribution, Bruner-Emmett-Teller (BET) and Barret-Joyner-Halenda (BJH) methods were employed.…”