RHEOLOGICAL STUDY OF COMPOSITES FOR 3D PRINTING APPLICATION IN THE BUILT ENVIRONMENT

Abstract

The application of 3-dimensional (3D) printing in the built environment is promising given the advantages it provides. This dissertation studies the rheological properties of composites that contains a range of constituents like polyvinyl alcohol (PVA), biochar, carbon soot etc. for their feasibility in extrusion-based 3D printing. The three tests that were carried out were flow ramp test, amplitude sweep and frequency sweep. From this study, the results showed that only SampleSodAlg which comprised of 9% sodium alginate and 8.33% CarbonX displayed rheological properties that indicates its feasibility in extrusion-based 3D printing. Firstly, based on the flow ramp test, it showed shear thinning behaviour. Secondly, the results from the amplitude sweep and frequency sweep suggests that the material is able flow out of the nozzle when an oscillatory motion and force is applied as it becomes more viscous than elastic. Once it is printed, it will reattain its originally dominant elastic properties while resting on the printing platform. From the results obtained, the minimum operating oscillation torque of the 3D printer shall be 5002 µN.m whereas the minimum angular frequency to be provided shall be 16 rad/s. The findings from this research however does not conclusively determine the feasibility or non-feasibility of the materials for extrusion-based 3D printing as there are many other parameters that affects the printing process that were not studied. This includes properties and behaviours like thixotropy, creep, surface tension, transition glass temperature etc.