目的 探讨木薯秸秆粉的粒径和含量对复合材料物理力学性能及界面结合的影响，以期提高废弃木薯秸秆的利用率。方法 以木薯秸秆粉为增强体，高密度聚乙烯(HDPE)为基体，马来酸酐接枝聚乙烯(MAPE)为偶联剂制备木塑复合材料。对木塑复合材料进行拉伸性能、弯曲性能、缺口冲击强度以及吸水性测试，并利用电子显微镜(SEM)对复合材料断面微观结构进行观察和分析。结果 随着秸秆粉含量的增大，拉伸强度和弯曲强度在整体上呈现出增大的趋势，最大值分别可以达到32.5 MPa和49.6 MPa，而缺口冲击强度不断下降;当粒径减小时，材料的拉伸强度呈现先下降而后升高的趋势，弯曲强度区别不大，而缺口冲击强度则整体上呈现降低的趋势。当秸秆粉的含量降低、粒径减小时，复合材料表现出较好耐水性能。结论 秸秆粉质量分数为60%，粒径为40～60目时复合材料具有较优异的综合性能，相关性能超过GB/T 24137—2009《木塑装饰板》的使用标准。

The work aims to discuss the effects of particle size and content of cassava straw powder on the physical and mechanical properties and interfacial bonding properties of the composites, so as to improve the utilization of waste cassava straw. Wood plastic composites were prepared with cassava straw powder as reinforcement, high density polyethylene (HDPE) as matrix and maleic anhydride grafted polyethylene (MAPE) as coupling agent. The tensile properties, bending properties, notched impact strength and water absorption of wood plastic composites were tested, and the cross-section microstructure of the composites was observed and analyzed by the electron microscope (SEM). With the increase of the content of straw powder, the tensile strength and bending strength on the whole showed an increasing trend, with the maximum values reaching 32.5 MPa and 49.6 MPa respectively, while the notched impact strength kept decreasing. When the particle size decreased, the tensile strength of the material firstly decreased and then increased, the bending strength had little difference and the notch impact strength decreased as a whole. When both the content of straw powder and the particle size decreased, the composites showed better water resistance. When the mass fraction of the powder is 60% and the particle size is 40～60 mesh, the composites have excellent comprehensive properties, and the relevant properties exceed the standard value of wood plastic decorative board (GB/T 24137—2009).