以造纸制浆废液中的碱木质素(AL)为原料,通过乙酰氯对其进行化学改性,制备出了乙酰化碱木质素(ACAL).红外光谱和核磁共振谱的结果表明乙酰化反应后AL中的羟基被乙酰基取代.ACAL在四氢呋喃(THF)和水的混合溶剂中能够通过自组装形成纳米级的球形胶束.利用静态光散射测定了胶束形成时的临界含水量,通过动态光散射研究了溶液初始浓度和水的滴加速度对胶束粒径和多分散性的影响,采用透射电镜和原子力显微镜对胶束形貌进行表征.结果表明,碱木质素经乙酰化改性后可用于制备木质素基球形胶束,并且胶束结构具有一定的稳定性,通过改变溶液条件可以在一定范围内调节胶束的粒径大小和多分散性.
Acetylized modification with acetyl chloride was carried out on alkali lignin (AL) which comes from pulping and papermaking industry,to obtain the acetylated alkali lignin (ACAL). The structural changes between AL and ACAL were characterized by infrared spectroscopy (IR) and nuclear magnetic resonance (NMR) ,and the results showed that the hydroxy groups in AL were displaced by the acetyl groups in ACAL. ACAL can form spherical micelles which are in the nonoscale by self-assembly in the mixed solvent of tetrahydrofuran (THF) and water. Static light scattering was used to monitor the forming process of the micelles and to measure the critical water content. The diameter and the polydispersity of the micelles were affected by the initial concentration of ACAL in THF and the dropping speed of water was studied, and were measured by the dynamic light scattering. The scanning electron microscope (SEM) and the atomic force microscope (AFM) were also used to characterize the feature of the micelles. Results show that the acetylized modification is a good method for perparing lignin-based spherical micelles with regular structure, and the structure also has a good rigidity and stability in the drying condition. The diameter and the polydispersity of the micelles can be controlled by the solution initial concentration and the water added speed. According to the analaysis,the π-π interaction between the aromatic nucleus in ACAL is stronger than in AL, and the stronger π-π interaction is considered to play an important role in the formation of the micelles.