Method for analysis of dynamic mechanical thermal analysis data using the Havriliak–Negami model

A new method is presented for analysis of single frequency dynamic mechanical thermal analysis (DMTA) data in the complex plane. The applicability of the method is restricted to cases where the polymer is thermorheologically simple and whose dynamic mechanical properties are well described by the Havriliak–Negami (HN) model. The method involved two steps: (1) the HN model was used to describe the shape of the complex plane representations of the DMTA data; and (2) the HN relaxation time (τ) was solved for at each temperature over which experimental measurements were made. This procedure resulted in the determination of four temperature independent HN parameters (α, β, E0, and E∞) and one temperature dependent parameter, τ(T). These model parameters were then used to calculate the dynamic mechanical properties over a range of temperatures and frequencies. The calculated moduli and loss factors were generally in good agreement with the experimental values for two elastomeric materials, neoprene and plasticized polyvinylchloride, that were subjected to the analysis procedure, over an 80° temperature range and three decades of frequency. It was also demonstrated that complex plane analysis of frequency multiplexed DMTA data could be used to calculate shift factors for time–temperature superposition. The corresponding master curves for storage modulus and loss factor created by horizontal shifts along the log(frequency) axis were smooth, providing additional support to the validity of the analysis procedure.