Study of Clay Nanocomposites of the Biodegradable Polyhexamethylene Succinate. Application of Isoconversional Analysis to Nonisothermal Crystallization

Nanocomposites of organomodified montmorillonites and the biodegradable polyester derived from hexanediol and succinic acid were prepared by the solution-casting method using chloroform as solvent. Samples were studied by means of X-ray diffraction and transmission electron microscopy. Intercalated structures differentiated by the stacking mode between silicate layers were observed. The highest variability in interlayer spacing was found when C30B organoclay was added. In this case, hydroxyl groups of the modifier could interact with polar carbonyl groups of the polyester. Thermal stability and crystallization behavior under both isothermal and nonisothermal conditions were evaluated. The overall crystallization rate of the intercalated nanocomposites was higher than that of the neat polyester due to a significant increase in their nucleation density, which compensated for their lower crystal growth rate. Isoconversional analysis was used to determine effective activation energies and to estimate nucleation and transport energy parameters from nonisothermal hot crystallization experiments.