Analysis of dynamic mechanical properties of photochemically crosslinked poly(isobornylacrylate-co-isobutylacrylate) applying WLF and Havriliak-Negami models

Chemically crosslinked poly (isobornylacrylate-co-isobutylacrylate) was elaborated by radical photo-copolymerization of isobornylacrylate and isobutylacrylate monomers in a 4:1 mass ratio, by adding a crosslinking agent at low concentration. The obtained copolymer was characterized by Fourier transform infrared spectroscopy for structural analysis, by differential scanning calorimetry for the determination of the glass transition temperature, and by thermogravimetric analysis to investigate thermal degradation effects. Storage modulus, dissipation modulus and tan delta were evaluated by dynamic mechanical analysis and modeled using different physical approaches such as the time-temperature superposition principle and the Havriliak-Negami model. The Cole-Cole curve was fitted with the Havriliak-Negami model yielding five parameters which were used to calculate the dynamic mechanical properties of the copolymer over a large frequency range from 1.03 × 10−4 Hz to 7.58 × 107 Hz. Calculated elastic and dissipative moduli agree well with the experimental data.