The calorimetric glass temperature was measured for three cyclic polystyrenes with apparent molecular weights ranging from 4.0 × 10 3 to 195.5 × 10 3 g/mol for both bulk material and for samples freeze-dried from dilute solution. Freeze-drying from dilute solution was found to reduce the glass temperature by 7 to 14 K depending on the sample. These T g depressions are 5 to 12 K greater than those found previously for freeze-dried linear polystyrene. Annealing at 403.2 K and 443.2 K (130 °C and 170 °C) resulted in recovery of the T g back to the bulk value with the time scales depending on both temperature and the magnitude of the T g reduction; the low apparent activation energy dependence of the recovery of T g precludes its being due to viscous flow.
|Number of pages||6|
|State||Published - 2004|
|Event||ANTEC 2004 - Annual Technical Conference Proceedings - Chicago, IL., United States|
Duration: May 16 2004 → May 20 2004
|Conference||ANTEC 2004 - Annual Technical Conference Proceedings|
|Period||05/16/04 → 05/20/04|