Some physical organic chemistry of aging processes

• Published in: Polymer engineering and science 1969-07, Vol.9 (4), p.282-285
• Main Authors: Mayo, F. R., Irwin, K. C.
• Format: Article
• Language: English
• ISSN: 0032-3888; 1548-2634
• DOI: 10.1002/pen.760090408

Work at Stanford Research Institute on the deterioration of polymers is based on the assumption that aging in the light is the most serious problem and that it has at least three components that must be separated if we are to understand the overall process. We have started by measuring the production of free radicals on the polymer when pairs of t‐butoxy radicals are generated from thermal decomposition of di‐t‐butylperoxy oxalate (DBPO) in bulk atactic polypropylene at temperatures approximating service conditions, 35–50°C. Our preliminary experiments have brought out experimental difficulties and have raised more theoretical questions than they have answered. Nevertheless, they show that the efficiency of production of polymer radicals is low and sensitive to the mobilities of the polymer chains. They also suggest that two kinetically different oxidation processes, with different dependencies on rates of initiation and with different susceptibilities to inhibitors, are proceeding simultaneously. The implications of these findings for results of some previous work and for design of improved accelerated tests is considered.