Abstract:

According to the presence situation that lignin-based SiO₂ composite nanoparticles are difficult for industry application, owing to serious aggregation and low lignin capacity, phosphatized alkali lignin (PAL) was prepared through phosphorylation reaction using alkali lignin (AL) from the alkaline pulping spent liquor of poplar as main material. The lignin/silica composite nanoparticles (L-SiO₂) was combined from 1 part nanosilica with 1.2 part (by mass) synthesized PAL by acidulation co-precipitation method. Subsequently, L-SiO₂ was added into HDPE to prepare L-SiO₂/HDPE composites. Results of FT-IR, XPS, TEM, TG and static contact angle showed that PAL was bonded to silica through hydrogen bonds. L-SiO₂ accounted for 47% (mass) LQA. Compared to crude silica, the particle size of L-SiO₂ increased from 25 to 40 nm and the agglomeration of particle decreased noticeably. More importantly, the surface of L-SiO₂ became more hydrophobic, which made them disperse better in HDPE. The tensile strength and elongation at break of prepared L-SiO₂/HDPE composites were 48.68% and 73.57%, respectively, higher than those of AL/HDPE.

Key words: alkali lignin, silica, phosphatized alkali lignin, nanomaterials, HDPE

摘要：

针对目前木质素基SiO₂复合纳米颗粒聚集严重及木质素负载量低,难以应用的现状,以碱木质素为主要原料,先通过磷酸化改性制备磷酸化碱木质素,再利用酸析共沉法将1.2份磷酸化碱木质素与1份纳米SiO₂(均为质量份)复合制备了木质素-SiO₂复合纳米颗粒,并探究复合颗粒对高密度聚乙烯(HDPE)力学性能的影响。FT-IR、XPS、TEM、TG和静态接触角测试结果表明,木质素主要以氢键作用与SiO₂结合;与原料二氧化硅相比,复合颗粒的粒径从25 nm增加到40 nm,聚集程度明显减弱;复合纳米颗粒中木质素占47%(质量分数);表面的疏水性增强,有利于复合颗粒在高密度聚乙烯中均匀分散,显著提高了HDPE的拉伸强度。与碱木质素/HDPE复合材料相比,木质素-SiO₂复合纳米颗粒/HDPE复合材料的拉伸强度和断裂拉伸率分别提高了48.68%和73.57%。

关键词: 碱木质素, 二氧化硅, 磷酸化碱木质素, 纳米材料, 高密度聚乙烯