不同预处理方法对木质素/低密度聚乙烯复合材料力学性能的影响

Effect of Different Pretreatment to Lignin on the Mechanical Properties of Lignin/LDPE Composites

采用球磨、气流粉碎和喷雾干燥等物理方法对麦草碱木质素分别进行预处理,制备不同结构特征的木质素颗粒。结果表明,气流粉碎木质素的平均粒径最小,为3.01μm,其次为球磨木质素和喷雾干燥木质素,平均粒径分别为16.02μm和27.23μm。气流粉碎木质素的比表面积最大,达到21.87 m2/g,球磨和喷雾干燥木质素的比表面积分别为2.61 m2/g和1.90m2/g。将3种预处理方法制备的木质素颗粒分别与低密度聚乙烯(LDPE)熔融共混制备木质素/LDPE复合材料,结果表明,在木质素质量分数相同时,采用喷雾干燥木质素制备的复合材料的拉伸强度比气流粉碎木质素大0.4MPa,比球磨木质素大1.5MPa。微观结构分析表明,喷雾干燥木质素在LDPE中分散最均匀,与LDPE相之间的结合力较好。

The wheat straw alkali lignin was treated by ball milling, jet milling, spray drying to prepare the lignin particles with different structure. The results show that the jet milling lignin has the finest particle size of 3.01 μm, then the ball millinglignin and spray drying lignin, with the particle size of 16.02μm and 27.23 μm. The jet milling lignin has the maximum specific surface of 21.87 m2/g, then the ball milling lignin and spray drying lignin, with the specific surface of 2.61 m2/g and 1.90 m2/g. These three prepared lignin were respectively blended with LDPE to prepare lignin/LDPE composites. The results show that the tensile strength of the composite prepared by spray drying is 0.4MPa higher than that prepared by ball milling and jet milling, and 1.5MPa higher than that prepared by ball milling with the same lignin amount. The optical microscopy images and SEM images show that the spray drying lignin disperses uniformly in lignin/LDPE composites, and the combining power with LDPE phase is the best.