Page 281 - IJB-10-4

International Journal of Bioprinting 3D printing prosthesis for palatal fistula

3.3. Fabrication and characterization of light- of the CH of the PTMEG polyol, and the peak at 7.11 to
2
curable PU elastomers 7.21 ppm corresponds to the H of the N-H of the IPDI
Figure 4A and B shows that the PTMEG reacts with IPDI backbone. The number average molecular weight (Mn),
to produce an isocyanate (-NCO)-terminated PU pre- weight average molecular weight (Mw), and polydispersity
polymer, followed by the addition of HEMA to react with index (PDI) of the three PUs in Table 3 were tested by
remaining -NCO to form C=C terminated PU (light- gel permeation chromatography (GPC); the results are
curable polyurethane). The FT-IR spectra of the resulting presented in Table 2. As the molecular weight of PTMEG
products are shown in Figure 4C; for the NCO-terminated increased, the final synthesized PU product increased in
PU pre-polymers obtained in the first step, the characteristic terms of amount, and the polymer dispersity (PD) became
peak of the -NCO was observed at 2260 cm . After adding higher. The Mn and Mw of PU were significantly higher
-1
3
the HEMA, the C=C stretching vibration emerged at 1640 than that of PU (R = 2), and the Mn and Mw of PU
2
3
cm , but -NCO disappeared. The successful synthesis of (R = 2.5) were less than those of PU (R = 2). The viscosity
-1
3
light-curable PU was also confirmed by H-NMR spectra of printing ink can be influenced by the molecular weight,
1
(Figure 4D). The peak at 4.10 ppm corresponds to the H particularly when it is high, thereby impacting the accuracy

Figure 4. Synthesis and characterization of polyurethane (PU). (A) Schematic diagram of the material synthesis process. (B) Chemical formula of material
synthesis. (C) Characteristic FT-IR spectra of PTMEG grafted with NCO bond followed by olefinic bond (C=C). (D) Characteristic H-NMR image of PU
1
after grafting olefinic bond (C=C). Abbreviations: FT-IR, Fourier transform infrared; PTMEG, polytetramethylene ether glycol.

Volume 10 Issue 4 (2024) 273 doi: 10.36922/ijb.2516