- Author
- Chien, J. C. W. | Kiang, J. K. Y.
- Title
- Polymer Reaction. Part 12. Effect of Polymer-Bound Vanadium in Oxidative Pyrolysis of Poly(Isoprene).
- Coporate
- Massachusetts Univ., Amherst
- Sponsor
- National Institute of Standards and Technology, Gaithersburg, MD
- Contract
- NBS-GRANT-G7-9010
- Keywords
- pyrolysis | radicals
- Abstract
- Poly(isoprene has been derivatized through peracetic acid reaction to chemically bound vanadium, V-poly(isoprene). At about 3.4 weight percent of vanadium, the substance is found to have the same kinetics of non-oxidative thermal pyrolysis of normal poly(isoprene); the products are also the same for the two materials. In contradistinction, the characteristics of their oxidative pyrolysis are profoundly affected by the polymer-bound vanadium. Compared to normal poly(isoprene), the vanadium derivative oxidizes much more slowly, with 23 kcal. mole (-1) higher activation energy of reaction, has 100 deg C. higher self-ignition temperature, and is self-extinguishing upon ignition. The effect of vanadium is not to change the products of oxidative pyrolysis but is to suppress their formation. The results are interpreted to mean complexation of poly(isoprene) peroxy radicals with the vanadium ion to decrease the rate of propagation and increase the rate of termination.