title: Micro- and nano-hydroxyapatite as active reinforcement for soft biocomposites.
abstract: Pectin-based biocomposite hydrogels were produced by internal gelation, using different hydroxyapatite (HA) powders from commercial source or synthesized by the wet chemical method. HA possesses the double functionality of cross-linking agent and inorganic reinforcement. The mineralogical composition, grain size, specific surface area and microstructure of the hydroxyapatite powders are shown to strongly influence the properties of the biocomposites. Specifically, the grain size and specific surface area of the HA powders are strictly correlated to the gelling time and rheological properties of the hydrogels at room temperature. Pectin pH is also significant for the formation of ionic cross-links and therefore for the hydrogels stability at higher temperatures. The obtained results point out that micrometric-size hydroxyapatite can be proposed for applications which require rapid gelling kinetics and improved mechanical properties; conversely the nanometric hydroxyapatite synthesized in the present work seems the best choice to obtain homogeneous hydrogels with more easily controlled gelling kinetics.
authors.affiliation: Laboratorio di Biomateriali, Dipartimento di Chimica, Materiali e Ingegneria Chimica, 'G. Natta' and Unità di Ricerca Consorzio INSTM, Politecnico di Milano, Piazza L. da Vinci, 32-20133 Milano, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Munarin
authors.affiliation: Laboratorio di Biomateriali, Dipartimento di Chimica, Materiali e Ingegneria Chimica, 'G. Natta' and Unità di Ricerca Consorzio INSTM, Politecnico di Milano, Piazza L. da Vinci, 32-20133 Milano, Italy. Electronic address: paola.petrini@polimi.it.
authors.forename: P
authors.initials: P
authors.lastname: Petrini
authors.affiliation: Laboratorio di Biomateriali, Dipartimento di Chimica, Materiali e Ingegneria Chimica, 'G. Natta' and Unità di Ricerca Consorzio INSTM, Politecnico di Milano, Piazza L. da Vinci, 32-20133 Milano, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Gentilini
authors.affiliation: Dipartimento di Ingegneria Industriali, Unità di Ricerca INSTM, Dipartimento di Ingegneria Industriale, Università di Trento, Via Sommarive 9, 38123 Trento, Italy.
authors.forename: R S
authors.initials: RS
authors.lastname: Pillai
authors.affiliation: Dipartimento di Ingegneria Industriali, Unità di Ricerca INSTM, Dipartimento di Ingegneria Industriale, Università di Trento, Via Sommarive 9, 38123 Trento, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Dirè
authors.affiliation: Laboratorio di Biomateriali, Dipartimento di Chimica, Materiali e Ingegneria Chimica, 'G. Natta' and Unità di Ricerca Consorzio INSTM, Politecnico di Milano, Piazza L. da Vinci, 32-20133 Milano, Italy.
authors.forename: M C
authors.initials: MC
authors.lastname: Tanzi
authors.affiliation: Dipartimento di Ingegneria Industriali, Unità di Ricerca INSTM, Dipartimento di Ingegneria Industriale, Università di Trento, Via Sommarive 9, 38123 Trento, Italy.
authors.forename: V M
authors.initials: VM
authors.lastname: Sglavo
mesh_terms: D017886:Durapatite / Q000737:chemistry*; D006358:Hot Temperature; D020100:Hydrogels / Q000737:chemistry*; D007700:Kinetics; D053761:Nanocomposites / Q000737:chemistry*; D010368:Pectins / Q000737:chemistry*; D011208:Powders / Q000737:chemistry; D012212:Rheology; D013499:Surface Properties; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D020100:Hydrogels; D011208:Powders; D010368:Pectins; D017886:Durapatite
keywords: Biocomposites; Hydrogels; Hydroxyapatite; Pectin