title: Effect of hydroxyapatite nano-particles on morphology, rheology and thermal behavior of poly(caprolactone)/chitosan blends.
abstract: The effect of hydroxyapatite nano-particles (nHA) on morphology, and rheological and thermal properties of PCL/chitosan blends was investigated. The tendency of nHA to reside in the submicron-dispersed chitosan phase is determined using SEM and AFM images. The presence of electrostatic interaction between amide sites of chitosan and ionic groups on the nHA surface was proved by FTIR. It is shown that the chitosan phase is thermodynamically more favorable for the nano-particles to reside than the PCL phase. Lack of implementation of Cox-Merz theory for this system shows that the polymer-nano-particle network is destructed by the flow. Results from dynamic rheological measurements and Zener fractional model show that the presence of nHA increases the shear moduli and relaxation time of the PCL/chitosan blends. DSC measurements showed that nHA nano-particles are responsible for the increase in melting and crystallization characteristics of the PCL/chitosan blends. Based on thermogravimetric analysis, the PCL/chitosan/nHA nano-composites exhibited a greater thermal stability compared to the nHA-free blends.
authors.affiliation: Department of Polymer Engineering, School of Chemical Engineering, University of Tehran, Tehran, Iran.
authors.forename: Fereshte Mohammad
authors.initials: FM
authors.lastname: Ghorbani
authors.affiliation: Department of Polymer Engineering, School of Chemical Engineering, University of Tehran, Tehran, Iran. Electronic address: kaffashi@ut.ac.ir.
authors.forename: Babak
authors.initials: B
authors.lastname: Kaffashi
authors.affiliation: Department of Biomaterials, Iran Polymer and Petrochemical Institute, Tehran, Iran. Electronic address: p.shokrolahi@ippi.ac.ir.
authors.forename: Parvin
authors.initials: P
authors.lastname: Shokrollahi
authors.affiliation: KTH Royal Institute of Technology, School of Chemical Science and Engineering, Fibre and Polymer Technology, SE-100 44 Stockholm, Sweden.
authors.forename: Shahin
authors.initials: S
authors.lastname: Akhlaghi
authors.affiliation: KTH Royal Institute of Technology, School of Chemical Science and Engineering, Fibre and Polymer Technology, SE-100 44 Stockholm, Sweden.
authors.forename: Mikael S
authors.initials: MS
authors.lastname: Hedenqvist
mesh_terms: D048271:Chitosan / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D011091:Polyesters / Q000737:chemistry*; D012212:Rheology; D013696:Temperature
chemical_list: D011091:Polyesters; C016240:polycaprolactone; D048271:Chitosan; D017886:Durapatite
keywords: Chitosan; Hydroxyapatite nano-particles; Morphology; Poly(caprolactone); Rheology