Relaxation during polymerization on slow heating and the vibrational heat capacity of the polymers (Articolo in rivista)

Type
Label
  • Relaxation during polymerization on slow heating and the vibrational heat capacity of the polymers (Articolo in rivista) (literal)
Anno
  • 2007-01-01T00:00:00+01:00 (literal)
Alternative label
  • Ferrari C, Tombari E, Salvetti G, (*)Johari GP (2007)
    Relaxation during polymerization on slow heating and the vibrational heat capacity of the polymers
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Ferrari C, Tombari E, Salvetti G, (*)Johari GP (literal)
Pagina inizio
  • 024903 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
  • 127 (literal)
Note
  • ISI Web of Science (WOS) (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • (*) McMaster Univertity, Hamilton, Canada (literal)
Titolo
  • Relaxation during polymerization on slow heating and the vibrational heat capacity of the polymers (literal)
Abstract
  • The real and imaginary components of the complex heat capacity, C-p(') and C-p('), and C-p,C-app have been measured in real time during the linear chain polymerization on 12 K/h heating of six different (partially) polymerized states of a stoichiometric mixture of cyclohexylamine and diglycidyl ether of bisphenol A. Their C-p,C-app shows a sigmoid shape rise with different onset temperatures T-onset, which is followed by a deep exotherm as the viscosity decreases and further polymerization occurs at different rates. The rates of their enthalpy decrease on polymerization determined by subtracting C-p(') from C-p,C-app differ but C-p(') and C-p,C-app of their final states are the same. The relaxation time increases with polymerization and decreases with an increase in T. C-p(') rises in a sigmoid shape manner, and C-p(') shows a peak when the relaxation time of the polymerized state is equal to the inverse of the temperature modulation frequency, whether polymerization occurs or not. The unrelaxed or vibrational heat capacity C-p,C-vib of the polymers at T>T-onset is close to C-p of their glassy state at T < T-onset, showing that C-p difference between the equilibrium liquid and its glass is mostly configurational. This contradicts a calculation showing that C-p,C-vib change of a polymer (literal)
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