Depression of Tg in polystyrene by freeze-drying

Paul Bernazzani, Sindee L. Simon

Research output: Contribution to conferencePaperpeer-review


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 languageEnglish
Number of pages5
StatePublished - 2003
Event61st Annual Technical Conference ANTEC 2003 - Nashville, TN, United States
Duration: May 4 2003May 8 2003


Conference61st Annual Technical Conference ANTEC 2003
Country/TerritoryUnited States
CityNashville, TN


  • Entanglements
  • Glass transition temperature
  • Polystyrene


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