Enhancing the Mechanical Properties and Aging Resistance of 3D-Printed Polyurethane through Polydopamine and Graphene Coating

Abstract

Three-dimensional (3D) printing is a versatile manufacturing method widely used in various industries due to its design flexibility, rapid production, and mechanical strength. Polyurethane (PU) is a biopolymer frequently employed in 3D printing applications, but its susceptibility to UV degradation limits its durability. To address this issue, various additives, including graphene, have been explored to enhance PU properties. Graphene, a two-dimensional carbon material, possesses remarkable mechanical and electrical properties, but challenges arise in its dispersion within the polymer matrix. Surface modification techniques, like polydopamine (PDA) coating, have been introduced to improve graphene’s compatibility with polymers. This study presents a method of 3D printing PU scaffolds coated with PDA and graphene for enhanced UV stability. The scaffolds were characterized through X-ray diffraction, Fourier-transform infrared spectroscopy, mechanical testing, scanning electron microscopy, and UV durability tests. Results showed successful PDA coating, graphene deposition, and improved mechanical properties. The PDA–graphene-modified scaffolds exhibited greater UV resistance over time, attributed to synergistic effects between PDA and graphene. These findings highlight the potential of combining PDA and graphene to enhance the stability and mechanical performance of 3D-printed PU scaffolds.

Influence of Post-Processing on the Degree of Conversion and Mechanical Properties of 3D-Printed Polyurethane Aligners

“…A study by Jung-Hwa et al has detailed how oxygen, particularly in ambient air, can interfere with the curing process of photopolymer resins, leading to incomplete polymerization and compromised material properties [34]. This is particularly pertinent in UV-cured resins, where oxygen can quench the free radicals necessary for polymerization [14,61]. Furthermore, various strategies have been investigated to mitigate oxygen inhibition, including the use of inert atmospheres during curing and the development of oxygen-scavenging additives [62,63].…”

“…The conversion rate, indicating the degree of polymerization, directly correlates with the material’s performance characteristics [ 13 ]. Proper control over the polymerization process is crucial to tailoring polyurethane’s properties to specific application requirements [ 14 ].…”