Development of a Standard Test Method for Determining Oxidative Induction Time of Hydrocarbons by Differential Scanning Calorimetry and Pressure Differential Scanning

Abstract

Test methods under the auspices of ASTM Committee E37 on Thermal Measurements are being developed for determining the oxidative induction time (OIT) of hydrocarbons by differential scanning calorimetry (DSC) and pressure DSC. This test method,ASTM E1858, is applicable to hydrocarbons, for example, polyolefins and motor oils that oxidize exothermically in their analyzed form. The DSC method is used at ambient pressure, one atmosphere oxygen. The pressure DSC (PDSC) protocol is used at high pressure, 3.5 MPa or 500 psig, oxygen. The test specimen and reference aluminum pan are heated to a specific temperature, DSC at 195°C and PDSC at 175°C in an oxygen environment. Heat flow out of the specimen is monitored at the isothermal temperature until the oxidative reaction is manifested by heat evolution on the thermal curve. Statistically designed experiments aided in establishing the factors affecting the OIT. Sample pan type, pressure, temperature, and oxygen flow rate were observed as significant experimental parameters. The OIT is a relative measure of oxidative stability at the test temperature. A precision and bias statement has been developed by ASTM Committee E37 and is reported based on a recent national round robin.

Bio‐based Algae Oil: an oxidation and structural analysis

“…As shown in this figure, PDSC technique relies on exothermic process of oxidation which appears in the form of a peak in heat flow vs. time thermogram [25]. Therefore, oxidation stability of triglyceride vegetable oils can be determined using PDSC [26][27][28]. Here, OIT was determined as the intersection of the extrapolated baseline and a line tangent to the oxidation exotherm constructed at its maximum rate in the PDSC thermogram.…”

“…Alternatively, PDSC techniques relies on the fact that oxidation of an oil is an exothermic process during which a change in heat flow is observed [25]. Therefore, oxidation stability of triglyceride vegetable oils can be evaluated using PDSC technique, as kinetics of oil oxidation is often revealed as an exothermic peak [26][27][28]. In this technique, a vegetable oil triglyceride is typically kept at an isothermal temperature until an oxidation peak is observed.…”

Effect of Recycled HDPE with Pro-oxidant on the Photodegradation of HDPE Film

“…Oxidation induction time gives an indication of the oxidative stability of the polymer as well as the residual concentration of efficient antioxidant. On the other hand OIT is one of the methods to measure the stability of polyolefin material [15]; higher oxidation times indicate stability of the material against oxidation. Figure 6 and Figure 7 show the OIT result of HDPE film at different loadings of RSH and RDH without UV exposure.…”