Structure-Property Relationships in PHB-Based Copolymers and PHB/PLA Biocomposites Modified with Hydroxyapatite and...

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Polymer Composites

Background:

• Bone defect repair requires advanced biomaterials, with biopolymer composites and biocompatible fillers being a key focus.
• Polyhydroxyalkanoates (PHAs), particularly poly(3-hydroxybutyrate) (P(3HB)), are promising for regenerative scaffolds due to biocompatibility and osteoinductive potential.

Purpose of the Study:

• To evaluate the mechanical, thermal, and morphological property changes in P(3HB)-based composites with hydroxyapatite (HA) and chitosan (CS) fillers.
• To identify optimal filler concentrations for developing bone-mimicking nanocomposites for orthopedic applications.

Main Methods:

• Synthesis of P(3HB)-copolymers/HA, P(3HB)/CS, P(3HB)/PLA/CS, and P(3HB)/PLA/HA composites using melt extrusion compounding.
• Characterization of composite properties with varying filler contents (up to 70 wt.%).

Main Results:

• Composite modification led to decreased melting temperature, improved mechanical characteristics, and increased elasticity.
• High filler concentrations (beyond optimal) resulted in nanoparticle agglomeration and degraded physical-mechanical properties.
• Composites with 10-20 wt.% nano-hydroxyapatite and chitosan exhibited mechanical properties closest to bone tissue.

Conclusions:

• The developed nanocomposites, particularly those with 10-20 wt.% nano-hydroxyapatite and chitosan, show significant potential for bone defect regeneration.
• These materials are suitable for creating biodegradable implants in reconstructive orthopedics.