The objective of this investigation is to provide critical insights into the understanding of polymer crystallization. One of the fundamental questions in this field is whether crystal growth takes place by a direct liquid to crystal transformation (Lauritzen-Hoffman model) or whether it is mediated by a mesophase (Strobl model). To start addressing this question, we have measured the spherulitic growth rates of narrow molar mass poly(e-caprolactone) fractions at different temperatures and analyzed this data using the classical growth rate equation. Such analysis shows that the thermodynamic transition temperature controlling the crystal growth rate (equilibrium melting temperature for the LH theory and equilibrium amorphous-mesophase temperature for Strobl's model) increases systematically with molar mass. We then show that the growth rate at fixed undercooling exhibits power law behavior as a function of molar mass. The power law exponent is strongly dependent on undercooling, in disagreement with predictions from the LH model.

Influence of temperature and molar mass on the spherulitic growth rate of  poly(&epsi;-caprolactone)

243rd National Meeting (2012)

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