### Session D30: Multiphase Polymer Materials

2:30 PM–5:30 PM, Monday, March 13, 2006
Baltimore Convention Center Room: 327

Chair: Ali Dhinojwala, University of Akron

Abstract ID: BAPS.2006.MAR.D30.15

### Abstract: D30.00015 : Phase Transition Behavior of Isotactic Polypropylene Crystallized from a Homogeneous Melt

5:18 PM–5:30 PM

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#### Authors:

Xiaofeng Chen
Sanat K. Kumar
(Chemical and Biological Engineering)

Rahmi Ozisik
(Materials Science and Engineering, Rensselaer Polytechnic Institute)

The equilibrium melting behavior of helical structures in isotactic polypropylene (iPP) was studied by a Monte Carlo simulation. It was found that the melting of iPP helical structure was an exponential process at high temperatures (T $>$ 470 K), whereas it becomes highly stretched at low temperatures (T $<$ 400 K). An estimate of the melting temperature was obtained from a novel application of the second moment of the waiting time distribution for helix melting as described by Odagaki (T. Odagaki, \textit{Phys. Rev. Lett.} \textbf{1995}, 75, 3701). The calculated melting temperature was approximately 455 K, which is in surprisingly good agreement with experimental values. A second transition temperature was also observed at a lower temperature (T $\sim$390 K), which we can not explain by equilibrium considerations. We suggest that at this temperature, once a helix forms, it does not melt within the time scale studied.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2006.MAR.D30.15