Scope:

ASTM D3045 test defines the exposure parameters to determine the resistance of plastics to oxidation or degradation when placed in hot air for an extended period of time. Polymers or plastic materials exposed to elevated temperatures than the normal temperature for a longer period of time will undergo some degradation resulting in changes in their physical properties. This test practice can be helpful in predicting how materials will degrade or oxidize over time. This practice plays a vital role in the comparison of thermal weathering properties of substances at a single temperature.

Test Procedure:

For ASTM D3045 practice, all materials must be placed in the same equipment at the same time if tests are carried out at a single temperature. A minimum of four exposure temperatures are used to determine the relationship between temperature and a specified property change. The time period to produce the desired level of the property is about 9-12 months using the lowest temperature and about six months for the next higher temperature for the same level of the property. Similarly, third and fourth temperatures should generate a similar property change in three months and one month, respectively. The exposure temperature is selected as specified by ASTM D618. Generally, it is difficult to determine the effect of heat aging without test data, so it is required to begin the test only with short-term aging at one or two temperatures unless some data is obtained for conducting the test. One set of samples are tested for the selected property as stated by ASTM D3045. The remaining set of samples are exposed for the selected time intervals at the specified temperature. These samples are subjected to stated exposure conditions and then are tested. In case the effect of aging is expected without heat then a parallel set or unexposed samples are tested. Also, a method is established, if required, for cooling after oven exposure.

Video 01: Temperature and humidity test chamber

Sample size:

The total number and kind of test samples necessary should be as stated by ASTM D3045 to determine the specific property. A minimum of three replicates of each material should be used if there is no specification or agreement by all interested parties. 

Data:

95 % confidence interval
Analysis of variance
Regression

Conclusion:

ASTM D3045 determines the Heat Aging of Plastics Without Load and can predict how materials will degrade or oxidize over time