The effect of controlled intercalation on the mechanical performances and dimensional accuracy of material extrusion additive manufactured poly(lactic acid)/organo-montmorillonite nanocomposites

Although the material extrusion-based 3D printing (MEX-3DP) has the ability to construct functional complex nanocomposites based on two-dimensional (2D) nanomaterials, however, the interplay of exfoliation degree of 2D materials and MEX-3DP parameters has not been elucidated, which seriously limits the further design and application of MEX-3DP 2D materials towards low-cost device fabrication. In this report, we use the well-studied organo-montmorillonite (MMT) as model materials and systematically studied the effect of various intercalation degrees on the mechanical and geometrical performance of MEX-3DP organo-MMT reinforced poly (lactic acid) nanocomposites. It was elucidated that, different from traditional injection moulding process, the best performance of MEX-3DP samples is obtained from completely exfoliated organo-MMT. The effect of the intercalation degrees is correlated with the melt flowability, thermal expansion and the resulting voids size that essential for MEX-3DP processes. The structure and rheology analysis demonstrate that the high exfoliation degree of 2D materials is essential to compensate the weak interfacial bonding or shrinkage-induced poor mechanical properties. The findings provide a detailed insight into the 2D materials exfoliation on the MEX-3DP quality, which is meaningful for engineers willing to design MEX-3DP functional 2D materials, for next generation disruptive technologies and applications.