| With the growing scarcity of fossil energy, development and utilization of renewable biomass resources to obtain various types of Chemical products is becoming hot. This research is currently focused on the conversion of hemicelluloses and cellulose. However, there is only a little research on lignin, the only natural aromatic high-molecular compound that got from renewable resource. It is petroleum resources potential effective alternative. Therefore, it is great significance to research and utilization of lignin.In this paper, the separation of the lignin from pine nut shells has been studied by using a high-boiling alcohol as solvent. The separation processes are optimized. chemical composition of lignin is determined. The FT-IR, gel permeation chromatography,1H-NMR and thermogravimetic analysis are utilized to structurally characterize HBS lignin. Furthermore, HBS lignin replaces a part of polyethylene glycol to synthesize HBS lignin-based polyurethane with PAPI. HBS lignin polyurethane samples is structurally chacterized by using the infrared spectroscopy and scanning electron microscopy.Conclusions are as follows:(1) Single-factor experiment shows that the separation conditions are optimized as reaction temperature at200℃, the solid-liquid ratio at1:12, catalyst of6%, reaction time for2h, alcohol concentration at90%, lignin extraction rate up to70%.(2) The results of FTIR,1H-NMR, GPC and TG indicates that the purity of lignin is very high, and belong to guaiacyl-syringyl-based lignin with the number average and weight-average molecular weight around5000.(3) HBS lignin’s hydroxyl value is197.2mgKOH/g, which is in the range of commonly used industry polyurethane, so it is directly used for the synthesis of polyurethane.(4) HBS lignin-based polyurethane’s tensile strength and solvent resistance can increase with the HBS lignin’s increasing, but its elongation at break is decreased, which indicates that HBS lignin can be designed and prepared to different types of polyurethane. |
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