Study of relaxation mechanisms in structurally related biomaterials by thermally stimulated depolarization currents

Thermal-stimulated depolarization current (TSDC) experiments were performed on a series of tyrosine-derived polyarylates with different number of meth ylene groups in the backbone. The low temperature TSDC spectra (80-240 K) w ere analyzed at two different degrees of hydration to assess the effects of small amounts of loosely and tightly bound water in the observed complex b eta band. Higher temperature TSDC spectra (250-350 K) provided the alpha re laxation peaks associated with the glass transition temperature. The direct signal analysis (DSA) method allowed the deconvolution of the peaks into e lementary processes and the determination of their mean relaxation paramete rs. The variations in the low and high temperature polarization with the nu mber of backbone methylene groups were interpreted as a combination of flex ibility and entanglement phenomena. The dielectric manifestation of the dis entanglement effects was observed for the case of the longest polymer. (C) 2001 Elsevier Science Ltd. All rights reserved.