39. The course of autoxidation reactions in polyisoprenes and allied compounds. Part VI. The peroxidation of rubber

Chain Scission in the Oxidation of Hevea. I

“…Published estimates of the efficiency of chain scission during oxidation of raw hevea have been based largely on experiments at low temperature where oxidative scission may be expected to be relatively inefficient. 4 Tobolsky, Metz and Mesrobian6 have shown that the efficiency of scission should, and does, increase as the rate of oxidation increases, as has also been found here. The measurements of Tobolsky and co-workers were made with vulcanized rubbers; they observed a higher limiting efficiency than was found for raw hevea in this work.…”

Evaluation of thermal and oxidative stability of three generations of phenolic based novel dendritic fuel and lubricant additives

“…The oxidative degradation of organic materials has been studied for many years and materials derived from petroleum, such as fuels and lubricants, are particularly susceptible as a result of increasingly harsher conditions within a combustion engine. [4][5][6][7] High temperatures and pressures in the presence of air and metal surfaces or contaminants contribute to the acceleration of oxidative degradation. [8][9] The oxidation process of liquid hydrocarbons was first proposed by Bolland and Gee in 1946 who described a free radical pathway.…”

Kinetic studies in the chemistry of rubber and related materials. I. The thermal oxidation of ethyl linoleate

“…This quantitative aspect of the reaction is emphasized by the almost complete absence of such volatile products as water and carbon dioxide; in sharp contrast, during the thermal oxida tion of certain other olefinic materials, such as rubber, which give only fractional yields of peroxide, water and carbon dioxide are formed from the outset. * The active hydrogen estimations quoted on p. 223 show that the peroxide groups formed in the thermal oxidation of ethyl linoleate, as in the case of other olefinic substances (Criegee, Pilz & Flygare 1939;Farmer & Sundralingam 1942Farmer & Sutton 1942and Sutton 1944) are of the hydroperoxidic type. While no formal proof is offered here that these hydroperoxide groups are disposed in the a-position to a double bond, the observation (Bolland & Koch 1945) that the introduction of a hydroperoxide group may result in the formation of a conjugated diene chromophore in the oxidized molecule represents very strong evidence that the double bonds are not destroyed in the process.…”