Biodegradable PHBV Polymer-Based Scaffolds for Bone Tissue Engineering - Biodegradable Polymer-Based Scaffolds for Bone Tissue Engineering - page 51

Fig. 3.8 TGA traces of a PHBV and b 10 % HA incorporated PHBV composite scaffolds
Fig. 3.9 The effect of incorporation of HA nanoparticles on the compressive mechanical
behavior of HA/PHBV scaffolds (Sultana and Khan 2012 )
to compressive load than pure PHBV scaffolds. This is a clear demonstration of
the benefit of adding HA nanoparticles to reinforce polymeric scaffolds. There
was a three-fold increase in compressive modulus when 20 % of HA nanoparti-
cles was incorporated in the scaffolds. As shown in Fig. 3.9 , under the compres-
sive force, PHBV and HA/PHBV composite scaffolds underwent three stages of
deformation, which are commonly observed for porous structures (the so-called
“cellular structures” in solid mechanics) (Gibson and Ashby 1997 ). Under com-
pression, the scaffolds exhibited linear elasticity at low stresses followed by a
long plateau of cell wall collapse and then a regime of densification in which
the stress rose steeply. The linear elasticity is controlled by cell wall bending,
the plateau is associated with collapse of the cells (of the “cellular structure”)
and when the cells have almost completely collapsed, opposing cell walls touch,