Oxidative Destruction of Polyolefins

It is natural that rolling could not be a universal method of investigation. Hence most investigations use varied methods, based on a study of the absorption of oxygen in a closed system. This makes it possible 

The absorption of oxygen by the polymer, as Fig. 45 shows, proceeds with an appreciable induction period, when the rate of absorption of oxygen is extremely small [8]. Hence the value of the induction period can be used as a characteristic of the rate of the oxidation process. 

The value of the induction period T is sharply reduced with increasing temperature and change in the oxygen pressure [9]. Such a dependence is presented in Fig. 46. 

It is characteristic that a sharp variation of the value of r as a function of the oxygen pressure is observed only at pressures below 150-200 mm Hg. For such pressures the reciprocal of the induction period 1/ r is also proportional to the average rate of the initial stage of the reaction, directly proportional to the pressure (r Pq = const). A further increase in the pressure (to 120 atm in [10]) has very little influence on the variation of the induction period. After the end of the induction period the absorption of oxygen occurs according to a curve possessinga sharply pronounced autocatalytic character. 

05% by weight leads to a 10-fold increase in tan 6. In view of this, there are indications in the literature that the quantity tan 6 can be a measure of the content of carbonyl compounds. More profound oxidation leads to the formation of the -OOH, -OH, -COOH groups [12] in addition to C = O groups, the formation of various types of C-0 groups is observed [13]. 

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