Dense suspension rheology is an expanding field with a great deal of interest in advanced materials design and processing to enable enhanced functionality and mechanical performance. In the case of systems comprising high loading levels of rigid particles, e.g. where the suspending matrix is the soft minority component, both rheology measurement and processing of these materials becomes challenging. In the context of additive manufacturing (AM), which is revolutionizing manufacturing by enabling complex geometries and multimaterial structures that cannot be fabricated using traditional approaches, a number of unique rheological considerations must be examined both in terms of measurement and in design of material formulations that will be “printable” by an appropriate AM modality.
In this talk, I will focus on probing fundamental rheological considerations and practical measurement approaches to enable extrusion based AM of dense polymer matrix suspensions across multiple extrusion platforms. Our recent work in miniaturized capillary rheometry of dense suspensions offers a unique opportunity for increased throughput screening of formulation extrudability while minimizing material requirements. Additionally, I will highlight our work with dual-cure suspending matrices for DIW based processing, highlighting our efforts to develop new rheological protocol to address the concurrent thixotropic, UV curing and thermal curing solidification mechanisms in dense suspension DIW. Considerations such as particle geometry, size, size distribution and scattering will be discussed in terms of rheological protocol and “printable” formulation design.
