The crystallinity and melting of compatible poly(ϵ-caprolactone)/poly(styrene-co-acrylonitrile) (PCL/SAN) blends were monitored for samples prepared from both the melt and solution. The development of PCL crystallinity was observed to be dependent on both the blend composition and preparation technique. The glass transition temperature was observed to be a primary cause of the compositional dependence of crystallinity. Solution casting was found to be a technique capable of increasing crystallinity levels for some compositions. The melting behavior of the blends is rather complex. Solution-cast samples exhibited a single endotherm that decreased in temperature with increasing SAN concentration. Both thermodynamic and morphological effects are cited as possible causes of this behavior. Melt-crystallized samples exhibited dual-melting endotherms whose magnitudes vary with blend composition. The melting point of the lower temperature endotherm increased with increasing SAN concentration. A mechanism based on melting, recrystallization, and subsequent remelting is invoked to explain the behavior of the melt-crystallized specimens. Finally, problems encountered when calculating polymer-polymer interaction parameters directly from experimental melting data are discussed.
All Science Journal Classification (ASJC) codes
- Organic Chemistry
- Polymers and Plastics
- Inorganic Chemistry
- Materials Chemistry