TY - THES

T1 - Synthesis and Characterization of 3D-Printable Epoxy-Based Vitrimers

AU - Höller, Rita

N1 - no embargo

PY - 2022

Y1 - 2022

N2 - 3D-printing of photopolymers is a technology that offers possibilities for numerous applications, such as soft robotics, rapid tooling or biomedical devices. However, many resins used in 3D-printing rely on acrylates - entailing polymer networks with poor mechanical properties (e.g. low toughness) due to their crosslinking mechanism. Those features limit the utilization of 3D-printing especially in fields such as rapid tooling, where tough materials are necessary. The thesis at hand sought to combine the excellent printability of acrylic resins with the superior mechanical properties of epoxy resins in order to overcome those limitations. The creation of a polymer material, consisting of two interpenetrating networks, makes a processing through 3D-printing and subsequent thermal curing possible. Additionally, this thesis aimed at achieving high glass transition temperatures as well as vitrimeric properties. Vitrimers exhibit catalyzed exchange reactions between covalent bonds at higher temperatures, enabling them to undergo stress relaxation, healing or even recycling. In the course of this thesis, a 3D-printable resin with vitrimeric properties was developed based on an acrylate and an anhydride-epoxy network. Material properties were analyzed and by varying the ratios of acrylate-based and epoxy-based resin components, further insights into material behavior were gained. Thermal properties were determined through thermogravimetric analysis and dynamic mechanical analysis. Curing behavior was examined using differential scanning calorimetry and Fourier-transform infrared spectroscopy. Additionally, stress relaxation experiments and tensile testing were used to assess mechanical properties. The optimized resin exhibited a high glass transition temperature (112 °C) after undergoing digital light processing and thermal post-curing. Altogether the material developed is a promising candidate for applications in rapid tooling due to its thermal and mechanical properties.

AB - 3D-printing of photopolymers is a technology that offers possibilities for numerous applications, such as soft robotics, rapid tooling or biomedical devices. However, many resins used in 3D-printing rely on acrylates - entailing polymer networks with poor mechanical properties (e.g. low toughness) due to their crosslinking mechanism. Those features limit the utilization of 3D-printing especially in fields such as rapid tooling, where tough materials are necessary. The thesis at hand sought to combine the excellent printability of acrylic resins with the superior mechanical properties of epoxy resins in order to overcome those limitations. The creation of a polymer material, consisting of two interpenetrating networks, makes a processing through 3D-printing and subsequent thermal curing possible. Additionally, this thesis aimed at achieving high glass transition temperatures as well as vitrimeric properties. Vitrimers exhibit catalyzed exchange reactions between covalent bonds at higher temperatures, enabling them to undergo stress relaxation, healing or even recycling. In the course of this thesis, a 3D-printable resin with vitrimeric properties was developed based on an acrylate and an anhydride-epoxy network. Material properties were analyzed and by varying the ratios of acrylate-based and epoxy-based resin components, further insights into material behavior were gained. Thermal properties were determined through thermogravimetric analysis and dynamic mechanical analysis. Curing behavior was examined using differential scanning calorimetry and Fourier-transform infrared spectroscopy. Additionally, stress relaxation experiments and tensile testing were used to assess mechanical properties. The optimized resin exhibited a high glass transition temperature (112 °C) after undergoing digital light processing and thermal post-curing. Altogether the material developed is a promising candidate for applications in rapid tooling due to its thermal and mechanical properties.

KW - 3D-printing

KW - vitrimers

KW - rapid tooling

KW - epoxy resin

KW - photopolymer

KW - 3D-Druck

KW - Vitrimere

KW - Rapid Tooling

KW - Epoxidharz

KW - Photopolymer

M3 - Master's Thesis

ER -