title: Viscoelastic properties of composites of calcium alginate and hydroxyapatite.
abstract: Calcium alginate was reinforced with hydroxyapatite (HA) particles, whose dimensions were a few micrometres, with mass fraction, mf, values in the range 0-0.8. Cylindrical samples of these composite materials were subjected to cyclic compression in the frequency range f = 0.001-20 Hz; in these tests a sinusoidal load of amplitude 1 N was applied either side of a static compression of 2 N. Storage and loss moduli, E' and E'', respectively, were found to be independent of particle size; however, E' increased with frequency consistent with the materials undergoing a glass transition. Above frequencies of about 0.05 Hz, E' > E'' for all materials. For each frequency, the dependence of the moduli on log10f could be represented by a third order polynomial; these equations can be used to calculate E' and E'' for a range of compositions. Approximate values of (E*) = square root of E'2 + E''2 are predicted by a Reuss model.
authors.affiliation: School of Engineering, Metallurgy & Materials, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
authors.forename: I
authors.initials: I
authors.lastname: Wands
authors.forename: D E T
authors.initials: DE
authors.lastname: Shepherd
authors.forename: D W L
authors.initials: DW
authors.lastname: Hukins
mesh_terms: D000464:Alginates / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry; D017886:Durapatite / Q000737:chemistry*; D004548:Elasticity; D005898:Glass / Q000737:chemistry; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D006882:Hydroxyapatites / Q000737:chemistry; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D000071228:Polyelectrolytes; D011108:Polymers / Q000737:chemistry; D011208:Powders; D011312:Pressure; D013696:Temperature
chemical_list: D000464:Alginates; D001672:Biocompatible Materials; D003188:Composite Resins; D017886:Durapatite; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D006882:Hydroxyapatites; D000071228:Polyelectrolytes; D011108:Polymers; D011208:Powders