Advanced 3D printing of graphene oxide nanocomposites: A new initiator system for improved dispersion and mechanical performance

The integration of nanoparticles, such as Graphene Oxide (GO), with photo-curable polymers in 3D printing has garnered significant interest in recent years due to the potential to create functional nanocomposite materials. This study explores the challenges of achieving optimal dispersion of GO nanoparticles within the polymer matrix and the crucial role of photoinitiators in overcoming these limitations. Traditional photoinitiators, like TPO, commonly used for GO/polymer resins, have raised concerns about high toxicity and limited sensitivity to visible light, prompting the need for alternative initiating systems. In this research, we propose a two-component initiator system based on bis-(4-t-butylphenyl)iodonium hexafluorophosphate and photosensitizer N-{4-[(E)-2-(pentafluorophenyl)ethenyl]phenyl}-2,1,3-benzothiadiazol-4-amine (IOD/PS1) as a promising solution. This new initiating system not only ensures a more environment-friendly resin but also exhibits enhanced polymerization kinetics and compatibility with GO nano fillers. This study investigated the effect of the addition of nano-GO on the kinetics of the radical photopolymerization process, 3D printing, and final mechanical and thermal properties of the received products. TPO and PEGDA/H2O were used as reference systems. In addition, a new two-component initiator system was synthesized, which is an interesting alternative to the commercial TPO initiator that is widely employed in additive techniques. This publication presents the research procedure involving various techniques: real-time FTIR and photoreology. In addition, the possibility of creating three-dimensional structures from the newly developed photo-curable resins was verified. Finally, the morphologies and mechanical properties of the resulting 3D structures were compared. Within the work, we demonstrate the advantages of the two-component initiator in achieving uniform distribution of GO and fabricating high-quality materials. By applying IOD/PS1 initiating system we facilitated a more controlled and efficient polymerization process, reducing shrinkage-induced stresses and enhancing interlayer bonding. The result was the fabrication of high-quality, well-dispersed materials with tailored properties suitable for various applications, particularly in the biomedical field.