Article ID Journal Published Year Pages File Type
9694106 Thermochimica Acta 2005 6 Pages PDF
Abstract
Reversing and non-reversing heat flows on the heating process after isothermal aging of glassy atactic poly(methyl methacrylate) was measured by temperature modulated differential scanning calorimeter. The reversing and non-reversing heat flows of the non-aged sample were subtracted from those of the aged sample to investigate only the isothermal aging effects. The difference between the aged and non-aged sample was most significant in the sample aged at 100 °C in both the reversing and non-reversing heat flows. Starting temperature of the difference in the non-reversing heat flow became higher with the aging temperature. On the other hand that of the reversing heat flow was around 70 °C irrespective of the aging temperature. Based on these results it is suggested that recovery of the molecular mobility at the glass transition occurs by two steps.
Related Topics
Physical Sciences and Engineering Chemical Engineering Fluid Flow and Transfer Processes
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