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3D Printed PLA/HAp Biocomposites
Table 3. Reagents and composition of the simulated body fluid solution.
Chemical reagent Formula Weight (g or mL
weight (g/mol) in 1 L solution)
Sodium chloride NaCl, Univar 58.44 7.996 g
Sodium bicarbonate NaHCO , Loba Chemie 84.01 0.350 g
3
Potassium chloride KCl, TPC 74.55 0.224 g
Potassium phosphate dibasic anhydrous K HPO , Loba Chemie 174.18 0.228 g
2
4
Magnesium chloride hexahydrate MgCl·6H2O, Loba Chemie 203.3 0.305 g
Hydrochloric acid (1 M) HCl, LabScan 36.458 40 mL
Calcium chloride dihydrate CaCl ·2H O, TPC 147.02 0.278 g
2
2
Sodium sulfate anhydrous Na SO , Fisher Scientific 142.02 0.071 g
2
4
Tris buffer NH C(CH OH) Loba Chemie 121.14 6.057 g
2
2
3
A B C D E F

G H I J K L

M N O P Q R

S T U V W X

Figure 2. Digital micrographs of 3D printed polylactic acid (PLA)/hydroxyapatite: (A-F) PLA/0H; (G-L) PLA/5H; (M-R) PLA/10H; and
(S-X) PLA/15H.

mechanically inferior. The experimental density and true Where P refers to the true porosity (in percent),
porosity are presented in Figures 3A and B, respectively. ρ experimental refers to experimental density, and ρ theoretical
We can see that as the HAp loading was increased, in an refers to theoretical density. The literature theoretical
opposite manner the composites’ density decreased. On densities of ρ PLA and ρ HAp are 1.43 g•cm and 3.16 g•cm ,
−3
−3
the other hand, the porosity kept increasing, which means respectively .
[19]
that more voids were forming as more HAp was added.
Perhaps the tendency of HAp particles to agglomerate 3.2. Chemical composition
influenced the composites’ microstructure and developed The changes in absorbance or absence of certain peaks
two kinds of sites that were agglomerated and areas that in the FTIR spectra are presented in Figure 4. These
were porous as well. The true porosity was calculated absorption peaks can be attributed to functional groups
using the following equation:
that are present in HAp, in pure PLA, or in the composite
material. Peaks and functional groups originating from

−1
% () =−P1 experimental ×100 PLA were located approximately at 2996 cm and
 theoretical (3.1) 2945 cm (CH stretching). The peaks at 1748 cm ,
−1
−1
3
116 International Journal of Bioprinting (2021)–Volume 7, Issue 1