本发明公开了一种新型纳米木质素及其制备方法，所述新型纳米木质素具有高含量羟基、中等分子量，其平均粒径为306～1121nm，羟基含量为8 .7～2 0 m m o l / g ，重均分子量为2 0 3 5～3428g/mol。本发明的新型纳米木质素的制备方法中，以工业木质素为原料，氢氧化钠为催化剂，通过化学水解、超声处理和冷冻干燥制备出上述新型纳米木质素。相对物理法来说，本发明采用化学水解法制备的纳米木质素，具有显著提高木质素羟基含量、适度降低木质素分子量的优点，尤其适合取代石油基多元醇制备木质素基有机高分子聚合物。

The present invention discloses a novel nano lignin and its preparation method. The novel nano lignin has a high content of hydroxyl groups and a medium molecular weight, with an average particle size of 306-1121nm, a hydroxyl content of 8.7-20 mmol/g, and a weight average molecular weight of 2035-3428g/mol. In the preparation method of the novel nano lignin of the present invention, industrial lignin is used as the raw material, sodium hydroxide is used as the catalyst, and the novel nano lignin is prepared through chemical hydrolysis, ultrasonic treatment, and freeze-drying. Compared to physical methods, the nano lignin prepared by the chemical hydrolysis method of the present invention has the advantages of significantly increasing the hydroxyl content of lignin and moderately reducing the molecular weight of lignin, and is particularly suitable for replacing petroleum based polyols to prepare lignin based organic polymer.