Blends of bisphenol-A polycarbonate (PC) and poly(ethylene terephthalate) (PET) has been investigated by differential scanning calorimetry and scanning electron microscopy. Blends were prepared by screw extrusion and solution casting with weight fractions of PC in the blends varying from 0.90 to 0.10. From the measured glass transition temperature (Tg) and apparent weight fractions of PC and PET dissolved in each phase, it appears that PET dissolves more in the PC-rich phase than does the PC in the PET-rich phase. The composition-dependent values of the Flory-Huggins polymer-polymer interaction parameter were determined and found to be from 0.05M to 0.037 for extruded blends at 275°C and from 0.058 to 0.040 for solution casting at 25°C. The interaction parameter decreases with increasing PET concentration. This result is consistent with the values of the Tgs, the microscopy study, and the measured extrudate swell ratios which show that compatibility increases more in the PET-rich compositions than in the PC-rich compositions. The PC-PET blends are not microscopically miscible for all the blend compositions.
|Number of pages||21|
|Journal||Journal of Polymer Science, Part B: Polymer Physics|
|Publication status||Published - 1990 Aug 1|
ASJC Scopus subject areas
- Materials Chemistry
- Polymers and Plastics