Commercial lignosulfonates from different sulfite processes as partial phenol replacement in PF resole resins
| Autor: | Hendrikus W. G. van Herwijnen, Grigory Zinovyev, Ana Requejo Silva, Masoumeh Ghorbani, Johannes Konnerth, Falk Liebner, Enkhjargal Budjav |
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| Rok vydání: | 2017 |
| Předmět: |
Polymers and Plastics
Chemistry Sodium lignosulfonate Organosolv Dispersity 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Surfaces Coatings and Films chemistry.chemical_compound Ultimate tensile strength Materials Chemistry Phenol Organic chemistry Lignosulfonates 0210 nano-technology Curing (chemistry) Kraft paper Nuclear chemistry |
| Zdroj: | Journal of Applied Polymer Science. 135:45893 |
| ISSN: | 0021-8995 |
| Popis: | Four commercial spruce lignosulfonates representing the most common acidic, neutral, and alkaline sulfite pulping processes and varying significantly in molecular weight characteristics were tested as partial (40 wt %) phenol substitute materials for the manufacture of lignosulfonate-phenol-formaldehyde (LPF) resole resins. Similar as recently reported for technical lignins from nonsulfite pulping processes (kraft, soda, organosolv), all lignosulfonates of this study effectuated a faster viscosity gain during resole cooking compared to the lignin-free reference resin (1000 mPa s after 120 min vs. 250 min to reach 1000 mPa s). Sodium lignosulfonate featuring the lowest weight average molecular weight (Mw 5780 g mol−1) and dispersity (Ð 6.1) turned out to be superior to the other lignosulfonates with regard to curing rate (B-time; 3:37 min vs. 6:41–9:08 min) and tensile shear strength development under hot pressing (120 °C; TS,max = 5.64 N mm−2 after 8 min) for beech veneer strips glued together with the respective LPF resins. Calcium and magnesium lignosulfonates are less suited with regard to phenol replacement due to the poor performance of the respective LPF adhesives in terms of tensile shear strength (TS,max = 3.29–3.49 N mm−2 after 12 min) most likely caused by considerable amounts of side products formed in the course of formose-type reactions. Phenolation of the two promising lignosulfonates, that is, sodium and ammonium lignosulfonate, did neither considerably increase the rate of PF network formation during resin cooking and curing nor improve tensile strength development during hot pressing. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 45893. |
| Databáze: | OpenAIRE |
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