Mass spectrometric evolved gas analysis (MSEGA) study of the thermal decomposition of poly(1,2-acenaphthenediylidene) and poly(1,2-acenaphthylenylene) in vacuo

✍ Scribed by D. Price; C. Lukas; G.J. Milnes; R. Whitehead; I. Schopov

• Publisher: Elsevier Science
• Year: 1983
• Tongue: English
• Weight: 339 KB
• Volume: 19
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(83)90130-1

✦ Synopsis

Abstraet--A mass spectrometric study of the thermal decompositions in vacuo of two polyene polymers. poly(1,2-acenaphthenediylidene)-I and polyll,2-acenaphthylenylene)-ll, was performed in order to establish the differences between their structures. Evolution of repeating units from a chain depropagation process of both polymers was observed. Annealing of the polymers prior to decomposition changed the temperature at which maxima were observed on the MSEGA ion current temperature profiles. These profiles of both polymers after annealing became more similar in shape and temperature location. These changes in MSEGA behaviour as a result of annealing can be attributed to an equalisation of the single and double bonds in the structure of the polymers. The kinetic study of the thermal decomposition of non-annealed polymers showed that the decomposition reaction for polymer I is isokinetic, i.e. of the same kinetic mechanism, when the fraction of sample decomposed ":~" is in the range 0.4 0.7 with wdues of 127.8 + 3.6kJ mol 1 for the activation energy and 2.6 + 2.2 × 10 ~ s ~ for the A factor. Polymer II did not show cleareut isokinetic behaviour, the activation energy increasing from 99.4 kJ mol * at = 0.4~113.5 kJ tool-~ at :~ -0.7. This change is attributed to the structure of the polymer altering during the course of the decomposition. The differences in the thermal properties lead to the conclusion that there is a bond alternation in the polyene chains of both polymers.