Estimating the activation energy of crystallization in blends of poly L‐lactic acid and poly(propylene 2,5‐furan dicarboxylate) during isothermal melt crystallization using temperature dependent infrared spectroscopy

Abstract Blends of Poly‐L‐Lactic Acid (PLLA) and Poly(propylene‐2,5‐furan dicarboxylate) (PPF) which have similar thermal properties were prepared by melt‐mixing. The crystalline/crystalline blends were investigated by Differential Scanning Calorimetry, Polarized Optical Microscopy, Wide Angle X‐Ray Diffraction and temperature dependent Fourier Transform Infrared Spectroscopy. The presence of two glass transition temperatures (Tg) in the blends confirmed immiscibility. The X‐Ray diffraction pattern ruled out the formation of new crystal morphology. PLLA formed large negative birefringent spherulites while PPF spherulites were extremely small. The isothermal crystallization kinetics of the two polyesters in the blends were investigated by monitoring the absorbance intensities of the crystalline infrared bands at 711 cm −1 and 990 cm −1 for PLLA and PPF respectively. Both neat polyesters exhibited a slower crystallization rate, but their behavior varied in the blends. The activation energy (Ea) of crystallization of PLLA and PPF calculated using the Arrhenius equation were −96.58 and −148.59 kJmol −1 respectively. The E a of both polyesters increased as the content of PLLA in the blends increased. Temperature dependent FTIR was successful in determining the crystallization parameters in crystalline/crystalline blends of PLLA and PPF.