Creep of PVDF monofilament sutures: service performance prediction from short-term tests

Abstract

Isothermal short-term creep of poly (vinylidene fluoride) (PVDF) monotilament sutures was determined at several temperatures between 10 and 90degreesC under the stress of 10 MPa. Longterm service performance was predicted for 10 decades of time. The compliance master curve as a function of time fits a hyperbolic sine equation. The temperature shift factor as a function of the temperature a(T) (T) is accurately represented by a general equation based on free volume. A simple relationship between the two parameters of the equation is explored. The viscoelasticity of PVDF is also seen in dynamic mechanical analysis performed at the frequency of 1 Hz. The origin of the viscoelastic character well present in the deformability of the PVDF in service is due to the occurrence of the alpha(c) relaxation that is active at similar to50 degreesC (E" peak at 1 Hz). (C) 2003 Elsevier Science Ltd. All rights reserved.