Quantified Phase Diagram of PCL/PDO Using the Cole–Cole Plot Analysis

Abstract This study presents a novel quantitative approach for analyzing the phase behavior and miscibility of polycaprolactone (PCL) and polydioxanone (PDO) blends through rheological analysis. A polymer miscibility index (PMI) is introduced, derived from the Cole–Cole plot analysis in a bid to understand the underlying physics of polymer blends. The PMI defined using complex viscosities enables quantitative evaluation of blend miscibility under various temperature and composition conditions. A phase diagram is constructed using the methodology, describing the upper critical solution temperature behavior. PCL/PDO blends exhibit enhanced phase stability with increasing PDO content, suggesting that PDO has a dominant role in determining blend miscibility. This quantitative approach provides valuable insight for optimizing the processing conditions and composition ratios of PCL/PDO blend.