Oxidation induction period

Stability to oxidation (induction period method) Oxygenates content... 

Figure 2 The effect of stabilizer concentration on oxidation induction period. 1-polyamineaniline disulfide 2-po-lydiaminodiphenyloxide disulfide 3-polythiosemicarbazide disulfide 4-CaO-6.

K [29]. The experimentally measured values were the following the induction period t of decalin oxidation, induction period t2 of PP film oxidation in an atmosphere of dioxygen, induction period t3 of PP film oxidation in the dioxygen flow, and time of evaporation of a half of phenol t1/2 in a nitrogen atmosphere at T 403 K. The results are given below. 

Oil (Aa 4-38) determines oil content in a dried sample of oil-bearing material by extraction with petroleum ether. This method is specific for cottonseed, which first must be fumed with hydrochloric acid to prevent oil adsorption to the fiber. Additional methods exist for other oilseeds. Oxygen Stability Index (OSI) (Cd 12b-92) measures the oxidation induction period of fat sample (essentially the time for a sample to exhaust its antioxidant properties) under conditions of the test. 

Under oxygen conditions, two emission peaks were detected for stabilized polymer films, a weak emission due to the thermal history of the film and a second intense peak observed when the oxidation induction period is attained (Fig. 3.4). 

The first exotherm (205-250 °C) is caused by oxidation of ZDDP after its oxidative induction period, leading to the reaction of intramolecular isomerization. The second exotherm (250-280 °C) is thermal degradation of the ZDDP. A number of products of the thermal degradation at 280 °C can be seen in the gas chromatogram. 

A detailed study on the action of hindered phenols embedded in LDPE was performed when the stabilization effects of several phenolic additives were evaluated by chemiluminescence [02C1]. In Fig. 87 the oxidation induction periods for the ageing of stabilized LDPE are presented, where the protective action is evident for their usage in hard conditions of operation [97J2]. 

Simon, P. Kolman, L. (2001). DSC Study of Oxidation Induction Periods, J. Therm... 

Polybutene and crosslinked polyethylene oxidation induction periods have been determined by DTA [23]. 

The most common methods coupled with the three mentioned tests are those also used for evaluating thermal and thermo-oxidative stability, namely measurement of the oxidation induction period by the oxygen uptake test, manometry, DTA, DSC, TG, EGA and EGD in isothermal and nonisothermal (dynamic) conditions oven aging in static or circulating air at 50-150°C, chromatography UV, IR, ESR, NMR spectroscopy, chemiluminescence, viscosimetry, mechanical indices determination, etc. Other criteria refer to discoloration, embrittlement, cracking, loss of elongation, etc. Hydroperoxides concentration can... 

Chemiluminescence has been used for measuring the oxidation induction period in polyolefins [444, 722, 723, 1422, 1590] and nylon 66 [720]. 

Table 5 Effect of Processing on the Thermal Oxidative Induction Period of Polypropylene Containing BHT (2 g 100 g ) (Air Oven at 140...

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