A recent study explored the use of polymer nanocomposites as an alternative material in additive manufacturing applications for thermoplastics. Conducted by a PhD student at the University of Waterloo, the study focused primarily on nanocrystalline cellulose (NCC)—a derivative of wood pulp—as an additive for polycarbonate (PC). The NCC was put to the test in electrospinning and fused deposition modeling in 3D printing techniques, which are commonly observed in additive manufacturing.
According to Andrew Finkle, the study’s author, three material system fibers configured in six distinct designs were used in the electrospinning experiments in order to maximize the desirable outcome responses. These three material systems included NCC and PC in THF: DMF, NCC and PC in chloroform, and NCC and PA 6, 6 in formic acid. Three factors were used to determine the effects of each: fiber diameter, bead diameter, and bead density.
The NCC was found to significantly improve spinn ability in the THF: DMF material system. In contrast, the NCC in PC in chloroform produced the least desirable results.
In fused deposition modeling in 3D printing, composites such as thermoplastic starch (TPS) and NCC reinforced TPS were put to the test. These 3D-printed filaments were created on a benchtop scale extruder and a scale-up facility intended specifically for industrial production. A MakerBot Replicator 2X printer with G-code and optimized slicing parameters were used. Four factors were observed to identify mechanical properties: impact, tensile, flexural testing, and layer bonding artifacts.
The use of 3D printing was able to produce increased tensile and flexural properties. In fact, the integration of NCC itself resulted in an increase in tensile, flexural, and impact properties. This means that nanocomposite 3D printing could potentially be an ideal replacement for other applications. Scale-up trials were also successful at preparing 3D printing filaments.
Research and manufacturing involving additives has received considerable interest, with materials such as composite hydrogels, bronze PLA, and composite SLS being explored and tested. This interest follows a demand for wider functionality in additive manufacturing while creating unique features for distinct mechanical properties. With these findings, Finkle’s study has contributed to an ongoing innovative process.
The full paper can be found at https://uwspace.uwaterloo.ca/handle/10012/15665.
For more related news, check out how this new method allows the production of high performance nanofibers here.