Abstract Clay-based nanoscale filler materials are commonly used to impart unique and desirable properties to polymer resins. Small volume fractions of nanoclay have disproportionately large effects on stiffness, toughness, strength, and gas barrier properties of polymer matrices due to their high surface-to-volume ratio and platelet morphology. Recent work has suggested that highly loaded epoxy/clay/fiber mixtures possess desirable rheological properties for use as feedstock materials for direct-write 3D printing, but little is known about the effects of the deposition process on the resulting properties of the printed composites. In this work we characterize the effects of a functionalized nanoclay on the rheological properties and printing behavior of an epoxy resin in the absence of fiber reinforcements, and investigate the effects of clay content and the deposition process on the thermo-mechanical properties of the resulting 3D-printed epoxy/clay nanocomposites. The rheological properties of ink formulations containing up to 12.5 wt% nanoclay are measured using parallel plate rheometry, and the thermo-mechanical properties of the printed composites are measured using 3-pt flexural testing, dynamic mechanical analysis, and thermo-gravimetric analysis. Flexural strength values range from 80 MPa to 100 MPa for cast samples and printed samples tested transverse to the printing direction, and up to 143 MPa for printed samples tested parallel to the print direction. Although the observed anisotropic strength values indicate that the deposition process does impart orientation to the nanoclay, the strength in each direction is significantly greater than values reported for 3D printed thermoplastic composites, suggesting that the epoxy/clay system has high potential for further development as a 3D printing feedstock material.

中文翻译：

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用于 3D 打印的高强度环氧树脂纳米复合材料

摘要 基于粘土的纳米级填充材料通常用于赋予聚合物树脂独特和理想的性能。纳米粘土的小体积分数对聚合物基质的刚度、韧性、强度和气体阻隔性能具有不成比例的大影响，因为它们具有高表面积与体积比和片晶形态。最近的工作表明，高负载环氧树脂/粘土/纤维混合物具有理想的流变特性，可用作直写 3D 打印的原料材料，但关于沉积过程对打印复合材料所得特性的影响知之甚少。在这项工作中，我们表征了功能化纳米粘土在没有纤维增强材料的情况下对环氧树脂的流变特性和印刷行为的影响，并研究粘土含量和沉积过程对所得 3D 打印环氧树脂/粘土纳米复合材料的热机械性能的影响。使用平行板流变仪测量含有高达 12.5 wt% 纳米粘土的油墨配方的流变特性，并使用 3-pt 弯曲测试、动态机械分析和热重分析测量印刷复合材料的热机械性能。弯曲强度值范围为 80 MPa 至 100 MPa，浇铸样品和印刷样品横向于印刷方向测试，印刷样品平行于印刷方向测试的弯曲强度值高达 143 MPa。尽管观察到的各向异性强度值表明沉积过程确实赋予纳米粘土取向，