title: Frequency dependence of viscoelastic properties of medical grade silicones.
abstract: Cylinders of medical grade silicone elastomers, (29 mm in diameter and 13 mm thick), immersed in physiological saline solution at 37 degrees C, were investigated by dynamic mechanical analysis (DMA). A sinusoidal cyclic compression of 40 +/- 5 N was applied over a frequency range, f, of 0.02-100 Hz. Values of the storage, E', and loss, E'', moduli for the cylinders were found to depend on f; the dependence of E' or E'' on the logarithm (base 10) of f was represented by a third-order polynomial. Above about 0.3 Hz, the cylindrical specimens appeared to be undergoing the onset of a transition from the rubbery to the glassy state. There was no significant difference between results obtained at 37 and 23 degrees C; pretreatment of specimens in physiological saline at 37 degrees C for 24 h and 29 days had no appreciable effect on the results.
authors.affiliation: School of Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham, United Kingdom. axm503@bham.ac.uk
authors.forename: A
authors.initials: A
authors.lastname: Mahomed
authors.forename: N M
authors.initials: NM
authors.lastname: Chidi
authors.forename: D W L
authors.initials: DW
authors.lastname: Hukins
authors.forename: S N
authors.initials: SN
authors.lastname: Kukureka
authors.forename: D E T
authors.initials: DE
authors.lastname: Shepherd
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D004548:Elasticity; D006801:Humans; D008422:Materials Testing; D019736:Prostheses and Implants; D033081:Shear Strength; D012826:Silicone Elastomers / Q000737:chemistry*; D013718:Tensile Strength; D055682:Viscoelastic Substances / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D012826:Silicone Elastomers; D055682:Viscoelastic Substances