A Novel Multimaterial Additive Manufacturing Technique for Fabricating Laminated Polymer Nanocomposite Structures

Abstract

The objective of this research is to develop a novel, multimaterial additive manufacturing technique for fabricating laminated polymer nanocomposite structures that have characteristic length-scales in the tens of millimeters range. The three-dimensional (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 nanoscale 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 multimaterial 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 microcracks by the nanoscale fiber mats has been identified to be the underlying mechanism responsible for these improved mechanical properties. The thermogravimetric analysis (TGA) reveals that these improvements in the mechanical properties are obtained without drastically altering the thermal degradation pattern of the base polymer.

Scalable production of polymer nanofiber‐based ropes, cables, and coatings

“…The tensile properties of the nanofiber‐based ropes and cables were characterized at a strain rate of about 0.0093 s −1 with a custom‐built testing unit . Friction clamps were used in combination with a thermal glue to secure the ends of the ropes onto a Mikrotools DT‐110 precision motion platform (±1 µm positional accuracy).…”

“…Beyond applications to filters and fibrous coatings, this adaptation of the electrospinning process is also well‐suited for the 3D printing of fiber‐reinforced soft composites . This 3D printing process demonstrated by Spackman et al . involves the layer‐by‐layer integration of electrospun fibers into a UV‐curable polymer matrix that is dispensed from an inkjet nozzle.…”

“…involves the layer‐by‐layer integration of electrospun fibers into a UV‐curable polymer matrix that is dispensed from an inkjet nozzle. Because the nanofiber deposition head [Figure (a)] can be easily integrated onto the Spackman et al . 3D printing platform, it is expected to allow for a relatively easy deposition of a variety of fibrous mats during the 3D printing of fiber‐reinforced soft composites.…”

“…Recent innovations in the areas of smart textiles, biomedical manufacturing, soft actuators, and three‐dimensional (3D) printing of fiber‐reinforced soft composites have highlighted the need to develop manufacturing processes for multimaterial polymer nanofiber yarns and fibrous coatings. Figure (a‐c) outlines some of the key nanofiber architectures of interest in these applications.…”

“…Currently, there appears to be a dearth of manufacturing processes that can achieve this. The directed deposition of multimaterial fiber mats is particularly relevant to the nascent field of the 3D printing of fiber‐reinforced soft composites . The electrospinning‐based fiber mat manufacturing techniques used for this 3D printing operation are currently not capable of providing on‐the‐fly material switching capabilities while laying down the fibrous structures …”