ASTM D5721-08 (2018) pdf free.Standard Practice for Air-Oven Aging of Polyolefin Geomembrane.
The rate of change of a particular property as a functionof temperature may be evaluated using the temperatures andtimes outlined in Practice D3045.
Any correlation between this practice and natural life ofthese materials must be determined for the particular application in which the materials are to be used.Airoven aging can be used to evaluate and compare theperformance of various heat stabilizer packages.A controlled,forced-ventilation oven with substantial fresh air intake is recommended.Oven apparatus shallbe in accordance with Type 11B in Specification E145.
Conduct initial tests in the standard laboratory atmosphere as specified in Practice D618,and with specimensconditioned in accordance with the requirements of the ASTMtest method for determining the specific property or propertiesrequired.
When required,conditioning of specimens followingexposure at elevated temperature and prior to testing, unlessotherwise specified, shall be in accordance with Practice D618.8. Procedure.Allow the oven to equilibrate at the test temperature.The temperature shall be below the Vicat softening point of thematerial.Suspend the specimens for exposure below an ovenshelf in a way to maintain a distance of at least 20 mm betweenspecimens and to allow for the entire shelf with specimens tobe removed.Age for the specified time and temperature.
Rotate the shelves from top to bottom and from front toback once a week to ensure even exposure.
At the end of an aging interval,remove a set ofspecimens and allow them to cool.Test the specimens for theselected property in accordance with the appropriate testmethod, including provisions for conditioning.
This practice covers a means for estimating the resistance of polyolefin geomembranes to thermal aging in thepresence of air. Only the procedure for heat exposure isspecified, not the test method or specimen.The effect of heaton any particular property may be determined by selection ofthe appropriate test method and specimen.This practice should be used as a guide to comparethermal aging characteristics of materials as measured by thechange in some property of interest.This practice does notpredict thermal aging characteristics where interactions be-tween stress，environment,temperature，and time controlfailure.The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.ASTM D5721 pdf download.