In-situ X-ray and thermal characterization of nanocomposites in FDM 3D printing*

In-situ synchrotron WAXS simultaneously with high resolution infra-red imaging were used to study the correlation between the extrusion parameters, the filaments deposition directionality and the internal structure of the nanocomposite in 3D printing by placing an “open-walled” FDM printer in the beamline. We used microbeam synchrotron SAXS to study the variance in the crystalline macrostructure formed as function of radial position in the filaments (from core to adjacent interfaces). We used PLA and PP as the polymeric matrix and graphene nano-platelets and hexagonal boron nitride as the fillers due to their excellent mechanical properties and the potential in thermal management applications. We observed the effect of extrusion shear forces on the orientation of the nanoparticles and the influence of the particle/polymer interactions on the polymer crystallization. We show how thermal properties improved by directionality and transcrystallization. We used Raman, electron microscopy and rheological techniques to study the interactions between the polymer matrix and the nanoparticles.