It has been long known that polymers can be mixed with clay minerals, however, the ideas of microcomposites have been expanded recently to a new and emerging class of clay-filled polymers, called Polymer-Clay Nanocomposites (PCN), which has experienced the real breakthrough early in the past decade only. This is a novel class of composites that are particle-filled polymers for which at least one dimension of the dispersed particles is in the nanometer range with very low filler loading (usually 2–6% by weight). Due to the unique structure, specifically the high aspect ratio of these mineral fillers, the resultant high surface area provides similar reinforcing performance to that of traditional minerals and fibers used in polymers and yet does not increase density, since loading levels are low. Because of the nanometer size of the particles, which is smaller than the wavelength of visible light, the reinforced polymer remains transparent. Other characteristics of these composites include high barrier performance and improved thermal stability, which make these compounds suitable for many applications. This review aims to provide a brief current overview in exploring this new class of polymer composites.

Acrylonitrile butadiene styrene (ABS) is the oldest fused filament fabrication (FFF) material that shows low stability to thermal aging due to hydrogen abstraction of the butadiene monomer. A novel blend of ABS, polypropylene (PP), and polyethylene graft maleic anhydride (PE-g-MAH) is presented for FFF. ANOVA was used to analyze the effects of three variables (bed temperature, printing temperature, and aging interval) on tensile properties of the specimens made on a custom-built pellet printer. The compression and flexure properties were also investigated for the highest thermal combinations. The blend showed high thermal stability with enhanced strength despite three days of aging, as well as high bed and printing temperatures. Fourier-transform infrared spectroscopy (FTIR) provided significant chemical interactions. Differential scanning calorimetry (DSC) confirmed the thermal stability with enhanced enthalpy of glass transition and melting. Thermogravimetric analysis (TGA) also revealed high temperatures for onset and 50% mass degradation. Signs of chemical grafting and physical interlocking in scanning electron microscopy (SEM) also explained the thermo-mechanical stability of the blend.

Additive manufacturing (AM) is a rapidly expanding material production technique that brings new opportunities in various fields as it enables fast and low-cost prototyping as well as easy customisation. However, it is still hindered by raw material selection, processing defects and final product assessment/adjustment in pre-, in- and post-processing stages. Spectroscopic techniques offer suitable inspection, diagnosis and product trouble-shooting at each stage of AM processing. This review outlines the limitations in AM processes and the prospective role of spectroscopy in addressing these challenges. An overview on the principles and applications of AM techniques is presented, followed by the principles of spectroscopic techniques involved in AM and their applications in assessing additively manufactured parts.