UV-protected polyetheretherketone structures via vacuum arc enhanced 3D printing

Abstract The application of material extrusion in vacuum and its combination with physical vapor deposition techniques such as vacuum arc coating technology opens new possibilities of functionalization of polymers during additive manufacturing. This allows to modify polymer surface properties such as thermal and electrical conductivity or radiation resistance. This is in particular interesting for in-space manufacturing and medical applications. In this work, the applicability of surface functionalization for UV protection of polymers was investigated. Therefore, an aluminum-based coating was chosen as a protective coating. The UV resistivity was assessed by testing the tensile properties of the specimens before and after radiation in dependence of coating parameters. The experimental results indicate that specimens coated with an $$\hbox {Al}_{2}\hbox {O}_{3}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mtext>Al</mml:mtext> <mml:mn>2</mml:mn> </mml:msub> <mml:msub> <mml:mtext>O</mml:mtext> <mml:mn>3</mml:mn> </mml:msub> </mml:mrow> </mml:math> layer of $$\ge {200}\,\hbox {nm}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>≥</mml:mo> <mml:mn>200</mml:mn> <mml:mspace/> <mml:mtext>nm</mml:mtext> </mml:mrow> </mml:math> retain their tensile strength when compared to untreated specimens, even after exposure to UV radiation. Hence, a $${200}\,\hbox {nm}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>200</mml:mn> <mml:mspace/> <mml:mtext>nm</mml:mtext> </mml:mrow> </mml:math> thick coating is suitable to protect polymers from UV-C-induced degradation. This demonstrates the applicability of enhanced extrusion-based additive manufacturing as a promising method for in-space manufacturing, servicing and coating repair.