Descrição
Blends of chitosan and synthetic aliphatic polyesters
(polybutylene succinate, polybutylene succinate adipate,
polycaprolactone, and polybutylene terepthalate adipate)
were compounded with and without hydroxyapatite,
a bioactive mineral filler known to enhance osteoconduction.
The blends and composites were compression molded
with two different granulometric salt sizes (63–125 lm and
250–500 lm) having different levels of salt content (60, 70,
and 80%) by weight. By leaching the salt particles, it was
possible to produce porous scaffolds with distinct morphologies.
The relationship between scaffold morphology and
mechanical properties was evaluated using scanning electron
microscopy, microcomputed tomography, compression
testing, differential scanning calorimetry, small-angle X-ray
scattering (SAXS), and wide-angle X-ray scattering. The produced
scaffolds are characterized by having different morphologies
depending on the average particle size and the
amount of NaCl used. Specimens with higher porosity level
have a less organized pore structure but increased interconnectivity
of the pores. The stress–strain curve under compression
displayed a linear elasticity followed by a plateau
whose characteristics depend on the scaffold polymer composition.
A decrease in the salt particle size used to create
the porosity caused in general a decrease in the mechanical
properties of the foams. Composites with hydroxyapatite
had a sharp reduction in yield stress, modulus, and strain
at break. The melting temperature decreased with increased
chitosan content. SAXS results indicate no preferential crystalline
orientation in the scaffolds. Cytotoxicity evaluation
were carried out using standard tests (accordingly to ISO/
EN 10993 part 5 guidelines), namely MTS test with a 24-h
extraction period, revealing that L929 cells had comparable
metabolic activities to that obtained for the negative control.
; Boesel, L. F. 
