Thermal degradation behaviour of copolyurethanes based on hydroxy terminated polybutadienes and its hydrogenated analogs: thermogravimetric and pyrolysis-g.c. studies
✍ Scribed by K.J. Scariah; V. Sekhar; M. Rama Rao
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 435 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0014-3057
No coin nor oath required. For personal study only.
✦ Synopsis
Thermal degradation of hydrogenated hydroxy terminated polybutadiene (HHTPB) and copolyurethanes based on HHTPB and HTPB with varying compositions of HHTPB were studied by thermogravimetric and pyrolysis-g.c, techniques. HHTPB was found to decompose in two stages and the kinetic parameters as evaluated by different mathematical approaches were found to be nearly equal with E = 216 + 6 kJ mol ~, log A = 15.7 + 0.4 min ' and n = 0.7. The corresponding activation energy for the main stage decomposition of the copolyurethanes was found to decrease with increase in HHTPB content up to 20% and then increase. This behaviour was rationalized on the basis of increase in strain of the network initially and then increase in HHTPB triad probability at higher concentrations. Pyrolysis-g.c. results indicated that butadiene (BD) was formed as one of the decomposition products by two different mechanisms and the probable mechanisms are suggested. Copolyurethanes also behaved similarly and BD concentration was found to depend linearly on their composition.