Unusual Spherulite Radial Growth Rate Kinetics of Poly(ethylene adipate): Observation of a Double Maximum in Growth Rate Curve

Poly(ethylene adipate) (PEA) is an aliphatic polyester often blended in small amounts with aromatic polyesters in order to impart some of its biodegradability to the resultant blend. Hot-stage polarized-light microscopy and differential scanning calorimetry have been used to investigate the isothermal melt-crystallization kinetics and thermal behaviour of PEA. The unusual spherulite radial growth rate dependence on isothermal crystallization temperature exhibits two maxima. A change in spherulite morphology from banded to non-banded spherulites is associated with the phase behaviour anomaly. The results are interpreted in terms of traditional Hoffmann-Lauritzen growth kinetics.