Page 537 - IJB-9-6

International Journal of Bioprinting High-performance SrCS scaffolds via vat photopolymerization

Table 1. Curing parameter of SrCS-BTA composites
Component Exposure energy (mJ/cm ) Curing depth (μm)
2
SrCS 9 73.53
SrCS-20BTA 20 73.5
SrCS-30BTA 28 73.52
SrCS-40BTA 32 72.74

to the stretching vibration of the unsaturated C=C bond of shrinkage curves of the scaffold were obtained (Figure 5c
HDDA, which decayed substantially in the printed green and d), X/Y is the line contraction of length and width, and
body, indicating the complete reaction of HDDA in VPP. Z is the line contraction of height.
The printed green body showed well-connected internal In order to investigate the process of sintering
pore structures with a pore size of about 1 mm (Figure 4d). densification and determine the optimal sintering
The step-like features on the rods that were derived from temperature, we conducted thermal expansion
the layer-by-layer printing were observed in SEM images, measurements on green bodies and obtained their real-time
which could be fully densified under expected sintering relative density curves during heat treatment. Subsequently,
conditions and thus resulting in the desired mechanical we derived the densification rate by differentiating
performance. the densification curves . Typically, the temperature
[49]
3.3. Sintering densification and characterization corresponding to the highest densification rate on the curve
of scaffolds is considered to be the optimal sintering temperature. To
Before sintering, all green bodies were debinded to remove explore the sintering densification mechanism and obtain
sacrificial organic matter, and the process of debinding is the optimum sintering temperature, we measured the
shown in Figure 5a. After that, we estimated the sintering thermal expansion of green bodies and obtained their real-
temperature range according to the general sintering time relative density curves during heat treatment. Figure
[48]
temperature of CS-based ceramics and conducted a 6a shows that the SrCS green body started to densify from
predictive sintering experiment (shown in Figure 5b). 1000°C, and the densification rate reached the maximum
−1
Finally, the sintering temperature was determined in of 0.32 s with the corresponding temperature of 1270°C.
the range of 1100–1300°C, in which the sintering line After sintering at 1270°C for 2 h, the step-like features

Figure 4. (a) UV light absorption of SrCS-BTA composites. (b) Curing depth of SrCS-BTA composites at different exposure energies. (c) Fourier infrared
absorption spectra of the SrCS raw powder, suspension, and green body. (d) Photography and SEM image of the printed SrCS green body.

Volume 9 Issue 6 (2023) 529 https://doi.org/10.36922/ijb.1233