Correlation between interaction parameters and crystal morphology in PCL/CPE blends with varying chlorine in CPE

The correlation between the interaction parameters and crystal morphology in binary blends of poly(ε-caprolactone) (PCL) and chlorinated polyethylene (CPE) with varying chlorine content was investigated. Melting-point depression analysis provided quantitative evidence of partial miscibility between PCL and CPE, with stronger interactions observed at higher chlorine levels. The interaction energy density (B) decreases linearly with increasing chlorine content, indicating improved miscibility and potentially more homogeneous blends at higher chlorine concentrations. Morphological analysis revealed significant changes in PCL crystal shape with varying CPE and Cl concentrations. Pure PCL formed truncated lozenge-shaped crystals, whereas the addition of CPE resulted in curved S-shaped crystals with increasing bending angle. The crystal growth rate decreased with increasing CPE content, with a more pronounced effect observed for higher chlorine contents in the CPE. Atomic force microscopy analysis of ultrathin films revealed dendritic crystalline structures, suggesting diffusion-limited growth mechanisms influenced by the polymer chain mobility and crystallization rates. The chlorine content in CPE significantly affected its surface morphology, with a higher chlorine content promoting a more perfect crystalline structure. These findings advance our understanding of the structure-property correlations in PCL/CPE blends, offering valuable insights for tailoring blend characteristics to meet specific application requirements, especially in fields demanding precise regulation of compatibility and performance metrics.