Assessment of the Mechanical and Thermal Properties of Injection-Molded Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)/Hydroxyapatite Nanoparticles Parts for Use in Bone Tissue Engineering

Abstract

In the present study, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HHx)] was reinforced with hydroxyapatite nanoparticles (nHA) to produce novel nanocomposites for potential uses in bone reconstruction. Contents of nHA in the 2.5–20 wt % range were incorporated into P(3HB-co-3HHx) by melt compounding and the resulting pellets were shaped into parts by injection molding. The addition of nHA improved the mechanical strength and the thermomechanical resistance of the microbial copolyester parts. In particular, the addition of 20 wt % of nHA increased the tensile (Et) and flexural (Ef) moduli by approximately 64% and 61%, respectively. At the highest contents, however, the nanoparticles tended to agglomerate, and the ductility, toughness, and thermal stability of the parts also declined. The P(3HB-co-3HHx) parts filled with nHA contents of up to 10 wt % matched more closely the mechanical properties of the native bone in terms of strength and ductility when compared with metal alloys and other biopolymers used in bone tissue engineering. This fact, in combination with their biocompatibility, enables the development of nanocomposite parts to be applied as low-stress implantable devices that can promote bone reconstruction and be reabsorbed into the human body.

Blends of Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate) with Fruit Pulp Biowaste Derived Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate-co-3-Hydroxyhexanoate) for Organic Recycling Food Packaging

“…Moreover, both good mixture and compatibility between the two PHAs were expected to be attained since no indications of phase segregation were observed, even at the highest P(3HB- co -3HV- co -3HHx) content, that is, 50 wt%. However, the film fracture surfaces of the PHBV-based materials revealed the presence of some microparticles, which can be ascribed to nucleating agents added by the manufacturer, such as boron nitride [ 57 ]. In the case of the neat P(3HB- co -3HV- co -3HHx), one can observe the presence of some impurities in the form of small lumps, which can be related to organic traces of cell debris or fatty acids derived from the bioproduction process of P(3HB- co -3HV- co -3HHx).…”

Improved Performance of Environmentally Friendly Blends of Biobased Polyethylene and Kraft Lignin Compatibilized by Reactive Extrusion with Dicumyl Peroxide

“…[ 70 ] This happens when the temperature exceeds the α ‐relaxation of the biopolymer. [ 71 ] In particular, the storage modulus ( E′ ) of bioPE shows a value of 1485.6 MPa at −75 °C. Above the T g , bioPE becomes more and more ductile (increase in the viscous component) and the corresponding E′ values are remarkably reduced down to 118.2 MPa at 100 °C (more than 200 °C above its T g ).…”

“…It is also worth noting that uncompatibilized bioPE/KL blends, and specially REX‐compatibilized bioPE/KL blends with DCP offer lower tan δ values, which could indicate that these materials show a more elastic response, and therefore, they have the potential to store the applied load rather than to dissipate/loss it. [ 71 ]…”

Strategies for Enhancing Polyester-Based Materials for Bone Fixation Applications

“…These results illustrate the reinforcing behaviour of HA and the mechanical properties being a function of porosity [ 65 ]. The mechanical and thermal properties of injection-moulded poly(3-hydroxybutyrate-co-3hydroxyhexanoate) (P(3HB-co-3HHx))/hydroxyapatite nanoparticles (n-HA) parts for use in bone tissue engineering and bone fixation were assessed [ 66 ]. The addition of 20% nHA improved the mechanical properties; specifically, the tensile moduli and flexural moduli by approximately 60%.…”