Poly(methyl methacrylate)/expanded graphite (PMMA/EG) composites are prepared using water-assisted mixing extrusion (WAME) technique. Scanning and transmission electron microscopy micrographs show that the EG exhibits better exfoliation and dispersion in the composite samples prepared with water injection than that in those without water injection. More EG layer networks and stronger PMMA-EG interfacial interaction are formed in the composite samples prepared with water injection, which are confirmed by the results of the FTIR and rheological measurements and the linear fits of experimentally obtained tensile yield stresses. The composite samples with well exfoliated and dispersed EG layers exhibit higher thermal conductivity and mechanical properties, which are ascribed to lower interfacial thermal resistance and stronger interfacial interaction, respectively. Finally, a mechanism for promoted EG exfoliation and dispersion in the PMMA matrix during the WAME is interpreted by analyzing the combined effect of injected high-pressure water with the shear force provided by the extruder screw.

聚（甲基丙烯酸甲酯）/膨胀石墨（PMMA / EG）复合材料是利用水辅助混合挤出（WAME）技术制备的。扫描和透射电镜显微照片显示，与不注水的样品相比，在注水的复合样品中EG表现出更好的剥离和分散性。注水制备的复合样品中形成了更多的EG层网络和更强的PMMA-EG界面相互作用，这通过FTIR和流变学测量的结果以及实验获得的拉伸屈服应力的线性拟合得到了证实。具有良好剥落和分散的EG层的复合材料样品具有较高的导热性和机械性能，这归因于较低的界面热阻和较强的界面相互作用，分别。最后，通过分析注入的高压水与挤出机螺杆提供的剪切力的综合作用，解释了WAME过程中促进EG在PMMA基质中剥落和分散的机制。