A new multi-variable-measurement approach for characterizing and correlating the nanoscale and microscale morphology of crystal-amorphous polymer blends with melt-phase behavior is described. A vertical small-angle light scattering (SALS) instrument optimized for examining the scattering and light transmitted from structures ranging from 0.5 to 50 m, thereby spanning the size range characteristic of the initial-to-late stages of thermal-phase transitions (e.g., melt-phase separation and crystallization) in crystal-amorphous polymer blends, was constructed. The SALS instrument was interfaced with differential scanning calorimetry (DSC), and simultaneous SALS/DSC/transmission measurements were performed. We show that the measurement of transmitted light and SALS under H V (cross-polarized) optical alignments during melting can be used to reliably measure the thermodynamic (e.g., crystal melting and melt-phase separation temperatures) and structural variables (e.g., crystalline fraction within the superstructures and volume fraction of superstructures) necessary for describing the multiphase behavior of crystal-amorphous blends in one combined measurement. We also evaluate the orientation correlations of crystalline volume elements within the superstructures. Our results indicate that simultaneous measurement of transmitted light can provide a reliable estimate of the total scattering from density and orientation fluctuations and the melt-phase separation temperature of polymer blends. For solution-cast poly(⑀-caprolactone)/poly(D,L-lactic acid) blends, our multivariable measurements during melting provide the parameters necessary to generate a crystal-liquid and liquid-liquid phase diagram and characterize the solidstate morphology. This opens up the challenge to explore use of our vertical SALS instrument as a rapid and convenient method for developing structure-property relationships for crystal-amorphous polymer blends.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.