分别采用邻苯二甲酸二辛酯(DOP)、邻苯二甲酸二丁酯(DBP)、环氧大豆油(ESO)作为增塑剂制备碱木质素/HDPE复合材料.研究了不同种类增塑剂对复合材料力学性能的影响,结果表明,3种增塑剂都能提高复合材料的断裂拉伸率,其中DOP的效果最优,当DOP添加量为7.5phr,复合材料的断裂拉伸率达146.28%,比未添加增塑剂的样品高62.4%.添加DOP制备复合材料,研究DOP对复合材料力学性能、断面形貌、流变性能的影响.复合材料的力学性能结果表明DOP含量的增加有利于复合材料断裂拉伸率的提高;SEM表明DOP的添加使复合材料的断面变的更加粗糙,材料韧性提高;流变性能结果表明DOP能降低复合材料的表观黏度(η)和复数黏度(η),并且线性黏弹区随着DOP含量的增加而变窄,储能模量(G’)和损耗模量(G”)也逐渐下降.分析认为,DOP分子吸附包覆在木质素微颗粒的表面,抑制了木质素微颗粒在HDPE相中的团聚,改善了木质素在HDPE中的分散状况,同时降低了木质素分子和聚乙烯分子链之间的作用力,从而改善了复合材料的力学性能和流变性能.
Alkali lignin/HDPE composites were prepared respectively with dioctyl phthalate (DOP), dibutyl phthalate (DBP) and epoxidised soybean oil (ESO). The influence of plasticizer on mechanical properties of composites was studied. The results showed that these plasticizers could increase the elongation at break of composites and DOP had the best effect. With adding 7.5 phr DOP, the elongation at break of composites was 146.28%, much higher than that (83.8%) of composites without DOP. Composites were prepared with different contents of DOP to study the influence of DOP on mechanical properties, fracture morphology and theological properties of composites. The mechanical properties of composites showed that the increasing DOP content was beneficial to the increasing of elongation at break. The SEM showed that the fracture surfaces of composites became coarser with the addition of DOP, and the toughness of composites increased. The rheological properties showed that the addition of DOP can lower the apparent viscosity and complex viscosity of the composites, and the linear viscoelastic region turned narrow, the storage modulus (G') and the loss modulus (G") also gradually declined with the increasing DOP content. According to the analysis it was concluded that DOP can adsorb on the surface of lignin particles and suppress the agglomeration of lignin particles in HDPE, which may improve the dispersion of lignin particles in HDPE and reduce the interaction force between the lignin molecules and the molecular chains of PE, thus the mechanical properties and rheological properties of the composites were improved.