IADR Abstract Archives
Synthesis of PCL-based Polyurethane Prepolymer for DLP 3D Printing
Objectives: The objective of this study is to prepare a photo-curable resin with flexibility, biocompatibility and degradability for customized cartilage tissue engineering scaffolds using digital light processing (DLP) 3D printing technology. With a high resolution, DLP becomes an ideal method for fabricating scaffolds with complex structures. Because of the degradability of PCL and the flexibility of the polyurethane, PCL-based polyurethane prepolymers were therefore synthesized and further formulated into nine resins.
Methods: PCL diols were synthesized in 3 different structures via ring-opening reaction of ε-caprolactone on diethylene glycol, with the catalyst stannous octoate (24h, 130°C). Isophorone diisocyanate (IPDI) was reacted with 2-hydroxyethyl acrylate (2-HEA) (1.5h, 30°C) and the PCL diols synthesized previously (12h, 70°C) in sequence to form PCL-based polyurethane prepolymer. Nine resins composed of different percentage of PCL-based polyurethane prepolymer, modulators, fillers and photo-initiator were further tested with a DLP 3D printer.
Results: The FTIR spectra registered absorption peaks of urethane group at 3360cm−1 (NH, hydrogen-bonded), 2860–2950cm−1 (CH2 and CH3), 1727cm−1 (C=O) and 1526cm−1 (N-monosubstituted amides), respectively. Peaks at 1639cm-1 and 1617cm-1 are corresponding to the acrylic group. The viscosities are within the range of 1-5Pa●s which are acceptable for 3D printing. By changing the amount of modulators, the mechanical properties of the 3D printed resins could be adjusted. The 3D printed resins had compressive modulus ranging from 15 to 24 MPa, which is close to the cartilage. Cytotoxicity test indicated that the materials are non-cytotoxic. The degradation time of the materials is still in experiment.
Conclusions: The PCL-based polyurethane prepolymers was successfully prepared and formulated into 9 resins. The 9 resins showed some advantages e.g. flexibility, high printing resolution, biocompatibility and degradability. Moreover, with 3D printing technique, a complex structure could be reached. In the future, the PCL-based polyurethane prepolymer may be applied to customized cartilage tissue engineering.
Methods: PCL diols were synthesized in 3 different structures via ring-opening reaction of ε-caprolactone on diethylene glycol, with the catalyst stannous octoate (24h, 130°C). Isophorone diisocyanate (IPDI) was reacted with 2-hydroxyethyl acrylate (2-HEA) (1.5h, 30°C) and the PCL diols synthesized previously (12h, 70°C) in sequence to form PCL-based polyurethane prepolymer. Nine resins composed of different percentage of PCL-based polyurethane prepolymer, modulators, fillers and photo-initiator were further tested with a DLP 3D printer.
Results: The FTIR spectra registered absorption peaks of urethane group at 3360cm−1 (NH, hydrogen-bonded), 2860–2950cm−1 (CH2 and CH3), 1727cm−1 (C=O) and 1526cm−1 (N-monosubstituted amides), respectively. Peaks at 1639cm-1 and 1617cm-1 are corresponding to the acrylic group. The viscosities are within the range of 1-5Pa●s which are acceptable for 3D printing. By changing the amount of modulators, the mechanical properties of the 3D printed resins could be adjusted. The 3D printed resins had compressive modulus ranging from 15 to 24 MPa, which is close to the cartilage. Cytotoxicity test indicated that the materials are non-cytotoxic. The degradation time of the materials is still in experiment.
Conclusions: The PCL-based polyurethane prepolymers was successfully prepared and formulated into 9 resins. The 9 resins showed some advantages e.g. flexibility, high printing resolution, biocompatibility and degradability. Moreover, with 3D printing technique, a complex structure could be reached. In the future, the PCL-based polyurethane prepolymer may be applied to customized cartilage tissue engineering.