Waste paper fibers are potentially outstanding natural fibers as reinforcing fillers in thermoplastics.In order to improve dispersion uniformity,waste paper fibers are usually chemically modified in laboratory experiments.However,the cost of organic solvents is unacceptable in medium or enlargement production.In this study,alkali treatment was proved to be a promising pretreatment for waste paper micronization process.The influence of NaOH concentration,fiber content and MAPE content on the mechanical properties of the waste paper/polyethylene composites was investigated.The results showed that although NaOH treatment had a negative impact on mechanical properties,it could be reduced or even eliminated if the concentration was less than 3.5%.The flexural and tensile strength increased with the increase of paper fiber content from 30%to 40%.However,it reduced as the fiber content was more than 40%.The water absorption and thickness swelling was found to be proportional to fiber content.The effect of MAPE content on flexural strength was similar to that of fiber content.The highest flexural strength was obtain with 5%MAPE.Further addition of MAPE resulted a reduced flexural strength but a slightly increased tensile strength.On the contrary,the water absorption and thickness swelling was found to be inversely proportional to MAPE content.The SEM of impact fracture morphology of the composites showed that fibers were well dispersed in PE matrix and compatibility between fibers and PE matrix was greatly improved with the assistance of MAPE,which coincided with the enhanced mechanical properties.