title: Hydroxyapatite formation from cuttlefish bones: kinetics.
abstract: Highly porous hydroxyapatite (Ca(10)(PO(4))(6)·(OH)(2), HA) was prepared through hydrothermal transformation of aragonitic cuttlefish bones (Sepia officinalis L. Adriatic Sea) in the temperature range from 140 to 220°C for 20 min to 48 h. The phase composition of converted hydroxyapatite was examined by quantitative X-ray diffraction (XRD) using Rietveld structure refinement and Fourier transform infrared spectroscopy (FTIR). Johnson-Mehl-Avrami (JMA) approach was used to follow the kinetics and mechanism of transformation. Diffusion controlled one dimensional growth of HA, predominantly along the a-axis, could be defined. FTIR spectroscopy determined B-type substitutions of CO(3) (2-) groups. The morphology and microstructure of converted HA was examined by scanning electron microscopy. The general architecture of cuttlefish bones was preserved after hydrothermal treatment and the cuttlefish bones retained its form with the same channel size (~80 × 300 μm). The formation of dandelion-like HA spheres with diameter from 3 to 8 μm were observed on the surface of lamellae, which further transformed into various radially oriented nanoplates and nanorods with an average diameter of about 200-300 nm and an average length of about 8-10 μm.
authors.affiliation: Faculty of Chemical Engineering and Technology, University of Zagreb, Zagreb, Croatia. hivan@fkit.hr
authors.forename: H
authors.initials: H
authors.lastname: Ivankovic
authors.forename: E
authors.initials: E
authors.lastname: Tkalcec
authors.forename: S
authors.initials: S
authors.lastname: Orlic
authors.forename: G Gallego
authors.initials: GG
authors.lastname: Ferrer
authors.forename: Z
authors.initials: Z
authors.lastname: Schauperl
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry / Q000302:isolation & purification*; D001842:Bone and Bones / Q000737:chemistry* / Q000648:ultrastructure; D002119:Calcium Carbonate / Q000737:chemistry / Q000302:isolation & purification; D049832:Decapodiformes / Q000378:metabolism*; D017886:Durapatite / Q000138:chemical synthesis / Q000737:chemistry / Q000302:isolation & purification*; D006358:Hot Temperature; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D049329:Nanostructures / Q000737:chemistry / Q000648:ultrastructure; D043942:Nanotubes / Q000737:chemistry / Q000648:ultrastructure; D033362:Powder Diffraction; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D001672:Biocompatible Materials; D017886:Durapatite; D002119:Calcium Carbonate