Investigation on the mechanical properties of additively manufactured PETG composites reinforced with OMMT nanoclay and carbon fibers

Polymers and their composites have undergone massive development over the years through intensive research studies. The plethora of opportunities offered by these materials is greatly complimented by the advent of additive manufacturing. The present work analyses the mechanical properties of glycol-modified polyethylene glycol (PETG) reinforced with organically modified montmorillonite (OMMT) nanoclay and short carbon fibers (SCF). This work is the first of its kind to offer a complete overview of the mechanical properties of the composites prepared by these materials through 3D printing without the application of any post-processing techniques. These materials are initially compounded and followed by extrusion using a single-screw extruder to obtain fine filaments of 1.75 mm diameter. The specimens of PETG composite filaments were 3D printed as per the ASTM standards, using fused deposition modeling technique without any post-processing. The fabricated PETG/OMMT/SCF specimens are tested to study its tensile, compression, flexural, impact, and hardness properties. The fractured specimens from the tensile tests are analyzed using a scanning electron microscope. It is seen that the addition of OMMT nanoclay improves the properties of the composites by a significant extent for most of the tests. However, the addition of SCF has a negligible effect on the properties of the composites due to the presence of interstitial voids and poor matrix-fiber bonding. This calls for additional process parameter variations and post-processing techniques like pre-stressing, annealing, and others. These composites can be used in a wide variety of applications ranging from secondary structures in aerospace, automotive applications to minor orthotic and prosthetic applications.