Page 202 - IJB-8-1

3D Printing of a Graphene-Modified Photopolymer Using SLA

Figure 5. Fourier transform infrared spectra of C=C peak
(1637 cm ) of R with different times of ultraviolet exposure.
-1
Figure 7. Fourier transform infrared spectra of C=C peak
(1637 cm ) of R, R+G, R+GO, R+GoxNP after 5 min of ultraviolet
−1
cure.

Figure 6. Differential scanning calorimetry thermograms of R,
R+G, R+GO, R+GoxNP after 5 min of ultraviolet cure.
Figure 8. Polymerization degree versus ultraviolet polymerization
higher peaks than R and R+GO, confirming the lower UV time of R, R+G, R+GO, R+GoxNP.
polymerization degree.
When FTIR spectra were compared, the same On the other hand, R+G and R+GoxNP
tendency was observed. By studying the C=C peak showed similar tendencies regarding the evolution of
at 1637 cm (Figure 7), it is possible to compare the polymerization degree with time. The presence of these
-1
nanofillers showed a higher impact on the degree of
polymerization degree, which is more advanced when the polymerization when compared to GO, especially for
peak is less intense. relatively medium and long periods. They affect the
The FTIR results showed that R+G and R+GoxNP process, achieving lower polymerization degrees than the
followed the same trend when compared to the initial resin; this effect was especially notable in the case
observed DSC data. After 5 min of UV exposure, their of G.
polymerization degree was lower than in the case of the Table 4 shows changes in hardness as a function of
pristine resin and R+GO. UV polymerization time for the different nanocomposites.
Figure 8 showed the polymerization degree due to In all cases, hardness increased with time, showing that
the UV exposure (Eq. 3.1) and data presented in Table 3, the polymerization process was advancing. The trend
at different exposure times. It can be seen how GO observed in the hardness was similar to the obtained data
retarded the polymerization process for short UV times; from the DSC and FTIR analysis that the addition of G
however, from 5 min of UV exposure, the polymerization and GoxNP influenced the polymerization process of the
degree was similar to R. resin; they did not allow the resin to cure completely.

188 International Journal of Bioprinting (2022)–Volume 8, Issue 1