Hydrolytic thermal degradation of poly(naphthoyleneimide benzimidazole) in concentrated sulfuric acid
✍ Scribed by P. N. Lavrenko; O. V. Okatova
- Publisher
- John Wiley and Sons
- Year
- 1995
- Tongue
- English
- Weight
- 468 KB
- Volume
- 56
- Category
- Article
- ISSN
- 0021-8995
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✦ Synopsis
Translational diffusion in 96% H2S04 and intrinsic viscosity of poly(naphthoy1eneimide benzimidazole) (PNIB) have been investigated in different stages of its degradation in solution in the temperature range from 65 to 120OC. The degradation rate constant k has been determined from the change in molecular weight M of degraded products with time at the fixed temperature of solution. The activation energy of the process E was calculated from the temperature dependence of k. The difference in E values at low and high temperatures was found. At degradation temperatures above 90°C, the activation energy of hydrolysis was obtained as E = 133 kJ/mol, which coincides with that of aromatic polyamides in sulfuric acid. The data obtained are compared with the results of the investigations of optical properties of products of PNIB degradation in solution and PNIB stability in the solid state. An explanation of anomalies observed during PNIB degradation at low temperatures is suggested.