Official Journal of the Japan Wood Research Society
Table 1 The characterization of technical lignins
From: Conversion of technical lignins to functional materials with retained polymeric properties
| Â | Species | Hydroxyl group | Molecular weight | References | |||
|---|---|---|---|---|---|---|---|
Total | Phenolic | M w (×103) | M n (×103) | M w/M n | |||
(mmol/g)a | (mmol/g)a | ||||||
Kraft lignin | Softwood | 6.5–8.6 | 2.7–3.5 | 1.1–45.7 | 0.5–7.7 | 2.2–13.4 | |
|  | Hardwood | 6.5–8.4 | 4.3–4.7 | 2.4–4.8 | 0.4–1.3 | 1.8–12.0 | |
Lignosulfonate | Softwood | –b | 1.2–1.9 | 10.5–60.2 | 2.7–6.5 | 6.7–22.3 | |
|  | Hardwood | –b | 1.4–1.5 | 6.9–7.8 | 2.4–4.6 | 1.7–3.0 | |
Ogranosolv lignin (ethanol) | Softwood | 6.3–10 | 2.7–3.1 | 2.9–5.4 | 1.8–3.1 | 1.6–1.8 | |
|  | Hardwood | 5.7 | 2.8 | 2.0–2.6 | 1.3–1.6 | 1.5–1.6 | |
(Formic acid) | Miscanthus | 3.7–4.9 | 1.6–2.4 | 2.8 | 1.1 | 2.5 | |
(Acetic acid) | Hardwood | 5.5–5.8 | 3.5–4.0 | 0.9 | –b | –b | |
(Acetic acid/formic acid) | Wheat straw | 3.4 | 1.0 | 2.2 | 1.6 | 1.3 | [21] |