Plastics Technology Laboratories  

Void Content of Reinforced Plastics

ASTM D2734
(Test Method A)

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Void Content measures the voids in reinforced polymers and composites. Information on void content is useful because high void contents can significantly reduce the composites' strength. Monitoring lot-to-lot void contents can also act as a measure of the consistency of the composites' manufacturing process.

Test Procedure:
The measured density of the material is determined by dry / wet weight method ASTM D792 Method A. For void content it is necessary to have the theoretical densities of both the resin and the reinforcing material to determine the theoretical density. The individual densities are normally obtained from the supplier of the resin and reinforcing material.

After the actual density of the material is determined the weighed sample is placed into a weighed crucible and burned in a 600C muffle furnace in air until only the reinforcing material remains. The crucible is cooled and weighed. The resin content (ignition loss) can be calculated as a weight percent from the available data. By comparing the actual density to the theoretical density, void content is calculated.

Specimen size:
The size is normally 1 by 1 x thickness.

T = Theoretical Density V = Void content ( volume % )
Td = theoretical composite density Md = measured composite density
R = Resin weight % D = Density of resin
r = Reinforcement weight % d = Density of reinforcement
T = 100 / ( R / D + r / d ) V = ( Td - Md ) / Td

Equipment Used:
Muffle furnace
Mettler balance

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**Please note that this test description is intentionally generic in nature and aimed at providing a descriptive summary to enhance test understanding. For more information please contact a Intertek PTL Technical Representative at . Due to copyright restrictions, we are not able to provide copies of standards. Standards can be obtained from appropriate standards authorities.

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