非晶質ポリエチレンテレフタレートの物理的エージング 2.2段階温度ジャンプ後の等温体積回復

概要

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The dependence of physical aging kinetics on glass-forming histories and thermal treatments was examined for amorphous poly (ethylene terephthalate) (PET) glasses. The samples were subjected to two-step thermal treatment : first, temperature drop from equilibrium at 80°C to 60°C and then isothermal annealing ; second, temperature jump to aging temperature Ta. Isothermal volume recovery was measured after the second step to Ta (70°C> Ta>60°C) below the glass transition temperature (T<sub)g). The volume recovery curves were represented by a plot of normalized fractional free volume (=(V-V∞)/V∞, where V∞ is the equilibrium value of specific volume V) vs. logarithm of aging time. All curves, showing the well known “memory effect” characteristic, could be described nearly by a six-parameter phenomenological model postulating a multiplicity of independent relaxation modes with distinct relaxation times. The model parameters determined to fit the data were found to be greatly dependent on the glass-forming history, but weakly dependent on the thermal treatment conditions. Furthermore, the individual recovery curves could be superimposed by horizontal shifts along the logarithm axis of aging time.
一般社団法人　日本レオロジー学会の論文
1999-06-15