Title of article :
Activation energies derived from the pre-glass transition annealing peaks
Author/Authors :
Sergey Vyazovkin، نويسنده , , Ion Dranca، نويسنده ,
Issue Information :
دوهفته نامه با شماره پیاپی سال 2006
Abstract :
The paper explores the use of the DSC annealing peaks for estimating the activation energies of the β-relaxation in low and high molecular glassy systems. For the four studied systems that include d-glucose (dextrose), maltitol, poly(methyl methacrylate) and poly(ethylene terephthalate) the estimated values of the activation energy are 59 ± 10, 71 ± 6, 73 ± 12 and 75 ± 7 kJ mol−1. These values together with the activation energies determined earlier from the annealing peaks of polystyrene (PS), PS–clay nanocomposite, indomethacin, ursodeoxycholic acid and poly(vinylpyrrolidone) have been compared against the literature values of the activation energies of the β-relaxation. It is concluded that the DSC estimates typically do not deviate for more than 20% from the reference values obtained by the standard dielectric and mechanical methods.
Keywords :
?-Relaxation , DSC , kinetics , Polymer , Pharmaceuticals , Activation energy
Journal title :
Thermochimica Acta
Journal title :
Thermochimica Acta