A Novel Multi-Material Additive Manufacturing Technique for Fabricating Laminated Polymer Nanocomposite Structures

The objective of this research is to develop a novel, multi-material additive manufacturing technique for fabricating laminated polymer nancomposite structures that have characteristic length-scales in the tens of millimeters range. The 3D printing technology presented in this paper combines the conventional inkjet-based printing of ultraviolet (UV) curable polymers with the deposition of either aligned or random nano-scale fiber mats, in between each printed layer. The fibers are first generated using an electrospinning process that produces the roll of fibers. These fibers are then transferred to the part being manufactured using a stamping operation. The process has been proven to manufacture multi-material laminated nanocomposites having different 3D geometries. The dimensional accuracy of the parts is seen to be a function of the interaction between the different UV-curable polymer inks. In general, the addition of the nanofibers in the form of laminates is seen to improve the mechanical properties of the material, with the Young’s modulus and the ultimate breaking stress showing the most improvement. The pinning and deflection of micro-cracks by the nano-scale fiber mats has been identified to be the underlying mechanism responsible for these improved mechanical properties. The thermogravimetric analysis reveals that these improvements in the mechanical properties are obtained without drastically altering the thermal degradation pattern of the base polymer.