Oxidative induction test

Woo, L, Ding, S.Y. et ai. Riga, A.T., Patterson, G. H. (Hrsg) Chapter Further Studies on Oxidative Induction Test on Medical Polymers In Oxidative Behavior of Materials by Thermal Analytical Techniques, ASTM Publication, 1997... 

Oxidation. Based on the Norma-Hoff max oxidation bomb test, the phosphorus shall show the following oxidation characteristics Induction period — the minimum induction period shall be 20 hours. Oxidation rate — the maximum... 

ASTM D3895-07 Standard Test Method for Oxidative-Induction Time of Polyolefins by Differential Scanning Calorimetry, Book of Standards Vol. 08.02, ASTM International (formerly known as American Society for Testing and Materials), West Conshohocken, PA, USA. 

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. 

Figure 2. Oxidation induction time (OIT not the log-scale) for samples taken at a certain depth (0.9-1.0 mm from the inner wall from PB pipes pressure-tested at 90 C with internal chlorinated water (0.5, 1.0 and 1.5 ppm Cl) as a function of the exposure time. The line is a linear fit of the data. The insert figure shows the results of extrapolation to 01T= 1 min based on OIT data from exposures shorter than tfnax- From Lundback et al.(12) and with permission from Elsevier, UK.

The oxidation induction time can also be used as an indication of oxidation stability. No correlation has been determined between the results of this test and service performance. In the test (ASTM D-5483), a small quantity of grease in a sample pan is placed in a test cell. The cell is heated to a specified temperature and then pressurized with oxygen and is held at a regulated temperature and pressure until an exothermic reaction occurs. The extrapolated onset time is measured and reported as the oxidation... 

J.E. Volponi, L.H.I. Mei, and D. dos Santos Rosa, The use of differential photocalorimetry to measure the oxidation induction time of isotatic polypropylene, Polym. Testing 2004, 23, 461 165. 

ASTM RECOMMENDATIONS ASTM Tests for Oxidative Induction Time... 

ASTM D 3895 Standard Test Methodfor Oxidative Induction Time of Polyolefins by Differential Scanning Calorimetry Note of the author This procedure cannot be used for filled composite materials regarding Sampling section, particularly for those employing rather large filler particles. Instead of compression-molded test samples into sheet format prior to analysis to yield consistent sample morphology and weight and cut specimen disks (6.4-mm diameter) from the sheet to have a... 

ASTM D 5885 Standard Test Method for Oxidative Induction Time of Polyolefin Geosynthetics by High-Pressure Differential Scanning Calorimetry Principally, this is the same test as the above and is performed using a DSC, except now with a high-pressure cell that can sustain a pressure of 5500 kPa. The test is designed for highly stabilized materials. It is applicable only to materials whose... 

ADDENDUM TEST METHOD FOR OXIDATIVE INDUCTION TIME OF FILLED COMPOSITE MATERIALS BY DIFFERENTIAL SCANNING CALORIMETRY... 

ADDENDUM TEST METHOD EOR OXIDATIVE INDUCTION TIME... 

D 5885 (1997) Test method for oxidation induction time of polyolefin geosynthetics by high-pressure differential scanning calorimetry... 

E 1858 (1997) Oxidative Induction Time by DSC E 1867 (1997) Standard Test Method for Temperature... 

Finally, the researchers considered the PO s contact with copper wire over a cable s 50-year lifetime, and how this contact can contribute to "metal catalyzed thermal failures " Although the real-world tendency of a cable to oxidize over the long term is difflcult to measure in testing, these research ers evaluations showed that phenolic AOs, combined with a metal deactivator or chelator (see Table 3.1, for example), are effective in providing long oxidative Induction times at high temperatures. 

Oxidation induction time (OIT) measurements are less commonly performed, but they do provide some information about the oxidative stability of the UHMWPE. In this test, the DSC is heated to 200°C, then it is held isothermally. The purge gas, which is normally nitrogen, is then switched to pure oxygen. The time to the start of the degradation exotherm caused by oxidation is reported as the OIT. Open sample pans are used in this test technique. 

In addition, oxidative induction time, an exclusive test method popularly engaged in checking the suitability of an insulation material for cables, is added in the second edition. 

Oxidative induction time (OIT) provides an index useful in comparing the relative resistance to oxidation of a variety of hydrocarbon materials. The OIT procedure was first developed in 1975 by Gilroy and coworkers at Bell Laboratory as a test procedure to screen polyethylene insulation used in telephone wire and cable for its oxidation resistance. The method first became available as a Western Electric Specification and later as ASTM Test Method for Copper-Induced Oxidative Induction Time of Polyolefins. Polyolefin manufacturers quickly embraced the procedure and began to apply it to other applications including raw resins, finished pipes, wire and cable insulation, and, most recently, geosynthetic waste pit liners (ASTM D3895 2009). 

A series of high pressure oxidative induction time measurements (HPOIT) were conducted on a PE geomembrane sheet in order to investigate the interaction of the pressure and temperature variables on the induction time. The experiments consisted of determining the EffOIT at constant cell volume employing a wide operational range of pressure and temperature values. The HPOIT test results were found to be inversely related to both variables, with temperature being the predominant factor (Tikuisis et al. 1985). 

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