Mechanical properties of phb/maghemite nanocomposites determined by depth sensing indentation

L.A. FASCE; N. CABOT; C. E. HOPPE; F. RIVADULLA-FERNÁNDEZ; V. P CYRAS

Los Cocos, Córdoba

Simposio; V Argentine-Chilean Polymer Symposium, VIII Argentine Polymer Symposium y IX Chilean Symposium of Polymer Chemistry and Physical-Chemistry; 2009

Polyhydroxyalkanoates (PHA) are biodegradable polyesters attractive for applications in both medical devices and tissue engineering. These polymers can also be used as biodegradable implantable monoliths or microspheres for the sustained delivery of drugs. PHAs are produced biosynthetically by bacteria from natural raw materials under stress conditions. They are semicrystalline with very high degrees of crystallinity (60-80%) and essentially brittle. Crystallinity affects not only mechanical properties but also rate and mechanism of degradation, drug compatibility and drug diffusion (Pouton and Akhtar, 1996, Cyras et al, 2004). The incorporation of superparamagnetic nanoparticles (NPs) to these polymers would enhance their biomedical applications making them attractive for cell separation, magnetically driven drug delivery and hyperthermia (Tan et al, 2005; Hu et al, 2008). It has also been demonstrated that the addition of nanofillers to these matrices can enhance their thermal and oxidative stability and their mechanical and barrier properties. (Cyras et al, 2008, Hablot et al, 2008). The main objective of this work is to determine the effect of the addition of ultrafine maghemite NPs on the mechanical behavior of polyhydroxybutyrate (PHB)-based superparamagnetic nanocomposites. To this end, reduced elastic modulus, universal hardness and the resistance to permanent deformation are assessed using depth sensing indentation tests.