Free Volumes in Polymer Nanocomposites
We have employed positron annihilation lifetime spectroscopy to measure the free volumes in nanocomposites of polystyrene with addition of carbon nanofiber (CNF) and carbon dioxide as a function of composition and of temperature. We found that the glass transition temperature (Tg) increases as a function of CNF compositions but significantly decreases as the exposure of CO2. We also investigate the combination effect of CNF and CO2 and found that the CO2 significantly weakens the bonding between PS and CNF interfaces. The Tg changes are compared with DSC.
S. J. Wang, Z. Q. Chen, B. Wang and Y. C. Jean
H. M. Chen et al., "Free Volumes in Polymer Nanocomposites", Materials Science Forum, Vol. 607, pp. 177-179, 2009