Abstract
The calorimetric glass temperature of polystyrenes with molecular weights ranging from 3.0 × 103 to 43.7 × 106 g/mol are measured as a function of cooling rate for both bulk material and for samples freeze-dried from dilute solution. We find that Tg is depressed approximately 5 K for samples which can fully entangle and also the same amount for ultrahigh molecular weight samples which cannot achieve full entanglement. The lowest molecular weight samples show only 2 K depression on freeze-drying. Annealing eliminates the depression in Tg. The results indicate that the reduction of the glass temperature due to freeze-drying cannot be due to the reduced entanglement concentration induced by freeze-drying.
Original language | English |
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Pages | 1987-1991 |
Number of pages | 5 |
State | Published - 2003 |
Event | 61st Annual Technical Conference ANTEC 2003 - Nashville, TN, United States Duration: May 4 2003 → May 8 2003 |
Conference
Conference | 61st Annual Technical Conference ANTEC 2003 |
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Country/Territory | United States |
City | Nashville, TN |
Period | 05/4/03 → 05/8/03 |
Keywords
- Entanglements
- Glass transition temperature
- Polystyrene