Viscoelastic Response of Nanocomposite Polyvinyl acetate)-Hydroxyapatite With Varying Particle Shape-Dynamic Strain Softening and Modulus Recovery

摘要

Dynamic-strain softening known as the Payne effect was investigated in the case of polyvinyl acetate)-hy-droxyapatite (PVAc-HA) model nanocomposites in which the nanoparticles served as reversible physical crosslinks.HA nanofillers with different particle shape and with size ranging from 5 to 60 nm were used.Filler concentration in PVAc nanocomposites was limited to maximum of 5 vol%.Dynamic-mechanical spectra were recorded as a function of structural variables,strain amplitude,and test temperature using the dynamic-mechanical thermal spectroscopy (DMTS).Additionally,amplitude sweep tests were supplemented by the modulus recovery experiments to provide relaxation time data.Observed phenomena were interpreted using polymer physics approach.