Abstract: In this paper,the influence of different colorants on the color masking properties of lignin/HDPE (High- Density Polyethylene) composites was investigated,finding that the black color of lignin/HDPE composites can be effectively masked after the addition of iron oxide and that red composites with poor mechanical properties can be obtained.Then,different plastic additives were used to prepare red composites with improved mechanical proper- ties,and an elongation at break of 102. 43% was reached with the addition of 1 phr aluminium stearate,which is two times that of the composites without aluminium stearate.Melt index test results show that the molten red com- posites are of good flowing properties.Thermo-oxidative aging test results indicate that the red composites possess good thermal decomposition resistance.Rheological investigation reveals that the prepared red composites are pseu- do-plastic,with an apparent viscosity decreasing with the addition of aluminium stearate.And,SEM observation shows that lignin and iron oxide particles are homogeneously mixed in the HDPE phase.

Key words: lignin, high-density polyethylene, colorant, red composite, iron oxide