Melt growth rate and growth shape of Isotactic polybutene-1 tetragonal crystals

The morphology and lateral growth rate of isotactic polybutene-1 (PB1) has been investigated for crystallization from the melt over a temperature range of 50–110 °C. The morphology of the PB1 tetragonal crystals was a rounded shape at crystallization temperatures below 85 °C, whereas at higher crystallization temperatures, lamellar single crystals possessing faceted morphology were observed. The kinetic roughening transition occurred at approximately 85 °C. Regime II growth mode on faceted growth fronts does not operate below 85 °C as the growth faces are rough. The morphology was therefore indicative of regime III growth on rough surfaces. However, the growth rate showed a single temperature dependence derived from the nucleation theory and thus does not represent a regime II–III transition. Possible mechanisms for the crystal growth of PB1 are discussed.