PEN fibres are well known for their high performance properties, resistance, and good tensile properties. Their potential markets are the packaging, film and fibre markets. For tyre yarns in particular, the response to dynamic deformations at elevated temperatures is interesting. The ultimate modulus of PEN fibres is substantially higher than that of polethylenetrephtalate (PET). However, in the amorphous domains of PEN, the rotation of the naphthalene rings induces conformational transitions, which negatively influence the dynamic mechanical properties (Militký, 1999)
The main aim of this contribution is to measure and characterize the dynamic mechanical spectra of PEN fibres. These spectra are obtained at various levels of pre-straining. The analysis is based on the real part of the dynamic modulus and on an evaluation of the loss tangent. The simple model of dynamic behaviour based on the standard linear viscoelastic body is presented. The special apparatus for measuring dynamic behaviour under various types of deformation (tension, compression, bending, shearing) is described in detail.
