Morphology and glass transition behavior of polycarbonate–phenoxy system: Effects of trans-reactions in domain interface regions
✍ Scribed by E. M. Woo; S. N. Yau
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 314 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0887-624X
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✦ Synopsis
SYNOPSIS
Effects of trans reactions on the morphology, glass transition, and phase behavior in a classical blend system of a poly(hydroxyl ether bisphenol-A) (phenoxy) with bisphenol-A polycarbonate (PC) were investigated by differential scanning calorimetry (DSC) and optical microscopy. Although two T g s were observed in the as-prepared PC/phenoxy blends, an apparently single, but broadened, T g was found in the blends after heating at high temperatures, typically 200-250ЊC for short times. The optical microscopy results indicated that same scales of heterogeneity did exist in post-heated PC/phenoxy blends as well as unheated blends. Explanations were provided. After heating-induced interchange reactions ({OH and carbonate), randomly linked polymer chains might form at the numerous interfaces of the mutually occluded/included micro-domains. The majority of the chains in the micro-domains are forced to relax in coordinated motion modes after heating, thus showing a single T g . A mechanism of trans reactions in interfacial regions was briefly discussed in supplement to earlier reports in the literature.