Characterization of the kraft lignin: SEC molecular weight and polydispersity (PD), OH content according to ISO 14900 and 31P NMR.
Lignin | M w [g mol−1] | M n [g mol−1] | PDI | T g [°C] | OH content (ISO 14900) | Eq. weight [g mol−1] | Functionality | 31P – NMR | |||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
[mmol g−1] | (mg KOH) g−1 | Aliph. OH [mmol g−1] | Phenol. OH [mmol g−1] | Aliph./total [%] | OH aliph./molecule | OH arom./molecule | |||||||
pH 2 | 1879 | 574 | 3.3 | 148 | 2.67 | 150 | 375 | 1.5 | 5.0 | 3.6 | 59 | 0.9 | 0.6 |
pH 3 | 1732 | 538 | 3.2 | 147 | 4.48 | 251 | 223 | 2.4 | 7.3 | 5.9 | 55 | 1.3 | 1.1 |
pH 4 | 1570 | 441 | 3.6 | 143 | 5.02 | 282 | 199 | 2.2 | 13.3 | 12.5 | 51 | 1.1 | 1.1 |
pH 5 | 1502 | 490 | 3.0 | 134 | 5.35 | 300 | 187 | 2.6 | 19.0 | 18.2 | 51 | 1.3 | 1.3 |