Ammoxidized Fenton-Activated Pine Kraft Lignin Accelerates Synthesis and Curing of Resole Resins
| Autor: | Enkhjargal Budjav, Grigory Zinovyev, Johannes Konnerth, Thomas Griesser, Hendrikus W. G. van Herwijnen, Falk Liebner, Masoumeh Ghorbani, Ana Requejo Silva, Matthias Edler |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
0106 biological sciences
Materials science Polymers and Plastics lignin lignin ammoxidation 02 engineering and technology 01 natural sciences complex mixtures Article chemistry.chemical_compound Ammonia 010608 biotechnology Phenol formaldehyde resin Lignin Organic chemistry Phenol Ammoxidation Curing (chemistry) chemistry.chemical_classification technology industry and agriculture food and beverages General Chemistry 021001 nanoscience & nanotechnology automated bonding evaluation system (ABES) chemistry phenol formaldehyde resin ligneous adhesive Adhesive Fenton-type oxidation 0210 nano-technology Saponification |
| Zdroj: | Polymers; Volume 9; Issue 2; Pages: 43 Polymers |
| ISSN: | 2073-4360 |
| DOI: | 10.3390/polym9020043 |
| Popis: | Ammoxidation of pine kraft lignin in aqueous 5 wt % ammonia affords a novel type of phenol substitute that significantly accelerates resole synthesis and curing as demonstrated for 40 wt % phenol replacement. Compared to non-ammoxidized lignin, which already shortens significantly the cooking time required to reach a resole viscosity of 1000 Pa·s (250 vs. 150 s) and reduces the typical curing B-time by about 25% at 100 °C, the use of ammoxidized lignin has an even more pronounced impact in this respect. Activation of lignin by Fenton-type oxidation prior to ammoxidation further boosts both synthesis and curing of the resole. This is presumably due to the intermediary formation of polyvalent cross-linkers like N,N,N-tris (methylol) trimethylene triamine triggered by saponification of a larger fraction of nitrogenous moieties present in such a treated lignin (ammonium salts, amide-type nitrogen, urea) and reaction of the released ammonia with formaldehyde. Except for the fact that phenol replacement by ammoxidized lignin results in a somewhat less brittle cured adhesive polymer and higher elastic modulus, the aforementioned acceleration in curing could no longer be observed in the presence of wood, where a significantly delayed wood-adhesive bond formation was observed for the lignin-containing adhesives as evident from the automated bonding evaluation system. |
| Databáze: | OpenAIRE |
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