Direct measurement of the carbon dioxide-induced glass transition depression in a family of substituted polycarbonates
✍ Scribed by Tapan Banerjee; G. Glenn Lipscomb
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 177 KB
- Volume
- 68
- Category
- Article
- ISSN
- 0021-8995
No coin nor oath required. For personal study only.
✦ Synopsis
We present a method for the direct measurement of the glass transition temperature of compressed gas-polymer systems. The technique utilizes a Setaram C80D microcalorimeter equipped with high-pressure cells. Pressurizing the cells and running in scanning mode allows direct determination of the glass transition temperature. To validate the method, T g measurements of the CO 2 -poly(methyl methacrylate) system as a function of gas phase pressure were made. The results compare favorably with literature values. However, the effects of foaming appear to interfere with T g measurement at the highest gas pressures. The CO 2 -induced T g depression of a series of polycarbonates was also measured. The magnitude of the T g depression increases with decreasing glass transition temperature, reflecting an increase in intrinsic chain mobility, as evidenced by the glass transition temperature. The data correlate well with the Chow model.