Using polylactic acid with two particle size (20, 125 μm) as substrate material, respectively, and graphene as reinforcing material, the graphene/polylactic acid composite powders were prepared by ball milling, then pressed to two graphene/polylactic acid composites at 150 ℃.The bending performance and conductivity of the composites were studied.The results show that the graphene was coated on the surface of polylactic acid particles to form composite particles under the combining effects of mechanical interlocking and electrostatic adsorption.With the increase of graphene content, the bending strength of the two composites first increased then decreased, and the conductivity increased first rapidly then gently, and achieved relatively good values using polylactic acid with relatively small particle size.But too much graphene resulted in the defects on the surface of composites, such as cracks and broken.With the increase of molding pressure, the conductivity of the composite increased slightly, but the bending strength changed not obviously.%分别以两种粒径(20,125 μm)的聚乳酸为基体材料,石墨烯为增强材料,利用球磨法制备了石墨烯/聚乳酸复合粉,再在150 ℃下压制成两种石墨烯/聚乳酸复合材料,研究了其弯曲性能和导电性能.结果表明:在机械咬合与静电吸附共同作用下,石墨烯包覆在聚乳酸微粒表面形成复合微粒;随石墨烯含量的增加,两种聚乳酸复合材料的抗弯强度均先增大后降低,电导率则先快速增大后趋于平缓,且聚乳酸粒径较小时的复合材料性能更佳,但过多石墨烯又会使复合材料表面出现裂纹、破碎等缺陷;随着成型压力的增大,复合材料的电导率小幅度增加,但抗弯强度变化不明显.
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