BS EN ISO 4577:2019 pdf free.Plastics – Polypropylene and propylene-copolymers一Determination of thermal oxidative stability in air一Oven method.
5 Apparatus 5.1 Oven The oven shall be of mechanical convection type, capable of controlled circulation of air, with adjustable air intake and exhaust, equipped with a specimen holder and a temperature control system capable of adjustment to meet the following conditions. a) Exhaust rate: at least one oven-chamber volume in 10 min. b) Air velocity: from 0, 75 m/s to 1 m/s at any oven position occupied by the test specimens. c) Temperature control: range up to 200。C and with control throughout the working range to the nearest 1 °C. The temperature control shall include a device to prevent temperature overrides. It is  recommended that a device be used for recording the temperature inside the oven. 5.2 Thermometers Thermometers shall cover the temperature range up to 200 °C, graduated in 1 °C intervals or better. Each thermometer shall be tested for bulb stability and shall be calibrated at 150 °C. In order to control the homogeneity of the temperature in the oven, it is recommended that at least two thermometers be used, one in the upper part of the working volume of the oven, and one in the lower part. The test temperature is the mean value of the indications of the two thermometers.5.3 Specimen holder The specimen holder may be biaxially rotated, uniaxially rotated or stationary, provided that the test specimens are in a stream of air having a relative velocity between 0,75 m/s and 1 m/s. Illustrations of suitable apparatus for biaxially and uniaxially rotated specimen holders are shown in Figures 1 and 2, respectively. Biaxial rotation increases the probability that all specimens will be exposed similarly. In case of dispute, the use of biaxial rotation shall be the reference method.5.5 Die, to produce specimens of dimensions 50 mm x 10 mm from compression moulded sheet. 5.6 Metal clips, lined with fluorocarbon film or other materials that have no adverse effect on the oxidative stability of propylene plastics. BS EN ISO 4577 pdf download.